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Adaptive

Subclass of:

375 - Pulse or digital communications

375229000 - EQUALIZERS

375230000 - Automatic

Patent class list (only not empty are listed)

Deeper subclasses:

Class / Patent application numberDescriptionNumber of patent applications / Date published
375233000 Decision feedback equalizer 189
375234000 Fractionally spaced equalizer 7
375235000 Quadrature channels 5
20090141788BALANCING AMPLITUDE AND PHASE - A system for balancing a signal having I and Q components includes means for cross correlating the I and Q components to produce a cross correlation product; means for adjusting the gain of each I and Q signal component in accordance with said cross correlation product; and means for adding one component with the adjustable gain of the other component to produce a phase-balanced signal.06-04-2009
20090285278ADAPTIVE EQUALIZER AND RELATED METHODS - An adaptive equalizer. Implementations of adaptive equalizers may include implementations of 8-QAM adaptive equalizers that may include a signal filter, an adaptive processor coupled to the signal filter and a slicer coupled to the signal filter and the adaptive processor. The slicer may be configured to utilize a plurality of desired signals corresponding to an 8-QAM signal constellation having four quadrants, four levels disposed along the I-axis, and three levels disposed along the Q-axis. The slicer may also be configured to output an error signal by receiving an equalized output signal, processing the equalized output signal by correlating the equalized output signal with a decision region within one of the four quadrants, selecting one of a plurality of desired signals corresponding to the decision region, and calculating the error signal using the desired signal and the equalized output signal.11-19-2009
20080267278RETRANSMISSION OF REORDERED/CODED DATA IN RESPONSE TO PRESUMED RECEIVER DECODING FAILURE - A method having enhanced decoding operations associated with receiving multiple Radio Frequency (RF) Burst(s) is provided. Multiple RF burst(s) are received where the multiple RF Burst(s) include first RF bursts and second RF Burst(s). The second RF bursts may be transmitted in parallel or in response to a decoding error associated with the first RF burst. The received RF burst(s) are equalized and deinterleaved to yield extracted soft samples. Then the first estimated bit sequences and second estimated bit sequences are decoded from the extracted soft samples. A set of possible bit sequences may then be pruned based on based on combined knowledge of the first estimated bit sequence and the second estimated bit sequences. This pruned set may be compared using a sequence detector and the combined first estimated bit sequences and second estimated bit sequences to select a decoded bit sequence. This allows a sequence detector to use a combination of the original decoded data and the reordered decoded data as constraints when applying a turbo code technique to decode the data. The combination of the original coded data and reordered coded data results in a performance enhancement by providing further constraints.10-30-2008
20090052517Diversity GMSK-receiver with interference cancellation and methods therein - Method in a diversity antenna GMSK receiver of determining interference canceling equalizers and corresponding equalizers are described. The method includes providing a plurality of GMSK received signals; de-rotating and splitting each of the plurality of received signals into in phase and quadrature parts to provide a multiplicity of real valued branches; calculating linear equalizers for each of a multiplicity of subsets of the multiplicity of real valued branches; and providing an interference canceling equalizer for each of the multiplicity of real valued branches, each interference canceling equalizer corresponding to a weighted combination of the linear equalizers. A corresponding equalizer includes eight linear equalizers processing four branch signals corresponding to real (I) and quadrature (Q) parts of a GMSK diversity signal from two antennas, the linear equalizers calculated from four pairs of the four branch signals, with each pair having an associated timing parameter determined during calculation of two linear equalizers corresponding to the pair; and a weighting function for weighting the outputs from linear equalizers as adjusted by the associated timing parameter for each pair of the four branch signals to provide four weighted soft symbols; and a combiner for combining the four weighted soft symbols to provide soft symbols for the diversity signal.02-26-2009
20130101012FULL BAND CABLE RECEIVER - Systems and methods are described for the implementation of a full band cable receiver by using a combination of tuners (e.g., ultra-low power Tuners) and Analog-to-Digital Converters (ADCs) to attain the goal of digitization with reduced power and/or cost. The full-band capture cable receiver can overcome the constraints of conventional cable receiver systems and deliver multiple channels, thereby allowing operators to provide consumers with an increased number of services.04-25-2013
375236000 Accumulator or up/down counter 2
20110299585RECEIVING DEVICE AND RECEIVING METHOD - To optimize an adaptive equalizer with a simple controlling circuit, the receiving device includes a number counting part counting, in a range of detection having a predetermined width, a sampling result corresponding to the input signal being shaped by an equalizer circuit at a determination timing indicated by a clock signal obtained in a CDR circuit, a zone scanning part scanning the range of detection in a scanning zone including a variation range of the input signal; a coefficient altering part altering an equalizer coefficient set to the equalizer circuit; a peak detecting part detecting a peak value of a number of appearances of the sampling result according to alteration of the equalizer coefficient and scanning of the range of detection; and a coefficient specifying part specifying the equalizer coefficient being used when detecting the peak value in the peak detecting part as a first coefficient.12-08-2011
20130156088Adaptive Real-Time Control of De-Emphasis Level in a USB 3.0 Signal Conditioner Based on Incoming Signal Frequency Range - An apparatus comprises a differential equalizer having: a) a first differential input, b) a second differential input, c) a first differential output, and d) a second differential output; a frequency detector coupled to the first and second differential inputs; an amplifier coupled to a first differential output and a second differential output of the differential equalizer; and a logical combiner having a first input coupled to an output of the frequency detector and an output coupled to a control input of the amplifier, wherein the logical combiner can mask at least one received de-emphasis parameter.06-20-2013
Entries
DocumentTitleDate
20110002375Information reproducing apparatus using adaptive equalizer and adaptive equalization method - An adaptive equalizer includes: an equalizer configured to equalize a digital RF signal based on a plurality of tap coefficients; and a tap coefficient controller configured to correct the plurality of tap coefficients in a time division. The tap coefficient controller includes a tap coefficient register configured to hold the plurality of tap coefficients; and a product-sum calculating circuit configured to correct at least one selected from the plurality of tap coefficients in response to an enable signal, by a predetermined product-sum calculation, and update the selected tap coefficient by the corrected tap coefficient.01-06-2011
20090074049USE OF EMPHASIS TO EQUALIZE HIGH SPEED SIGNAL QUALITY - A method, apparatus, and system for minimizing ringing in a high speed channel between a transmitter and a receiver in a circuit, including a component for initializing an n-tap equalization filter. The n-tap equalization filter includes numerous taps, each associated with each of numerous jitter pulses received from the transmitter at the receiver and over the channel. Many of the jitter pulses are greater than two. Further, each tap occurs at a time-domain point related to a time of a corresponding jitter pulse included within the numerous jitter pulses. Moreover, a component for applying the n-tap equalization filter to a subsequent signal sent over the channel is also included.03-19-2009
20100008413Equalizer characteristics optimizing method and transmission system - An equalizer characteristics optimizing method includes acquiring a recovery clock timing from a reception signal; acquiring a predetermined sampling clock timing with respect to the recovery clock timing; latching the reception signal at the recovery clock timing; latching the reception signal at the sampling clock timing; comparing logic values obtained in the latching steps; collecting, after changing a characteristics setting of an equalizer, logic value comparison result data by repeating the recovery clock acquiring step, the acquiring of the sampling clock timing, the latching of the reception signal at the individual clock timings, and the comparing of the logic values, using the changed characteristics setting; and determining an optimum characteristics setting of an equalizer based on the collected logic value comparison result data.01-14-2010
20120183037EQUALISATION OF A SIGNAL RECEIVED OVER A WIRELESS CHANNEL - An apparatus, method and program for processing a signal received over a wireless channel. The apparatus comprises: a channel searcher configured to determine a profile of the channel in the form of energy values for a plurality of rays at respective channel positions, and an equaliser for equalising the signal based on a variable window of the equaliser. The channel searcher is configured to estimate dispersion of the channel by determining a measure of variance of ray distance from a reference position within the channel profile weighted by ray energy. The equaliser is coupled to the channel searcher and arranged to adapt the window in dependence on the measure of energy-weighted ray distance variance.07-19-2012
20090122855Systems and Methods for Mitigating the Effects of Upstream Far-End Cross Talk - Systems and methods for mitigating the effects of self-FEXT within an xDSL system are described. At least one embodiment is a method for reducing self-induced far end crosstalk (self-FEXT) in a multiple input multiple output (MIMO) digital subscriber line (xDSL) system. The method comprises deriving an initial value for an off-diagonal multiple input multiple output canceller (ODMC) while the ODMC is inactive and while in data mode. The method further comprises activating the initial ODMC and converging towards an steady-state value for the ODMC by performing an adaptive algorithm to maximize the Shannon's capacity of the system and to reduce upstream self-FEXT. The method also comprises performing bit loading and updating a frequency domain equalizer (FEQ).05-14-2009
20090122854FREQUENCY DOMAIN EQUALIZATION WITH TRANSMIT PRECODING FOR HIGH SPEED DATA TRANSMISSION - Various embodiments of multi input multi output (MIMO) communication systems include a transmit Tomlinson-Harashima Precoding (THP) technique and a single carrier frequency domain equalization (SC-FDE) technique. Parallel THP-FDE and successive THP-FDE are proposed based on the minimum mean square error (MMSE) criterion. For the successive THP-FDE technique, where all transmit streams are subsequently precoded, both suboptimal and optimal MMSE ordering algorithm are set forth. Since the feedback processing is performed at the transmitter, no error propagation problem exists in the THP-FDE MIMO techniques, yielding significant performance improvements over conventional FDE MIMO techniques. Applying channel prediction and THP compensation techniques can also further enhance performance.05-14-2009
20100074319Decoding system for LDPC code concatenated with 4QAM-NR code - A decoding system for LDPC code concatenated with 4QAM-NR code in a DTMB system is a two-stage decoding system. An NR decoder performs a 4QAM-NR decoding to obtain hard decision information. Then, the so obtained hard decision information together with corresponding soft symbol and channel state information are sent to a log-likelihood ratio (LLR) device for further computing a log-likelihood ratio after an adder adds a correction term associated with the hard decision information to a computed log-likelihood ratio without the hard decision information. An LDPC decoder receives the LLR for decoding.03-25-2010
20100074317TRUNCATION OF NOISY TAPS IN CHANNEL ESTIMATION - Methods and systems are described for processing a signal in wireless communications. The signal may have synchronization information. A method of processing a signal having synchronization information may include receiving the signal, and determining a truncation region of the time domain estimated channel, the estimated channel having taps. The method further includes processing the channel taps within the truncation region.03-25-2010
20100074318EQUALIZER, EQUALIZATION METHOD, PROGRAM AND RECEIVING DEVICE - An equalizer includes: a replica generation means for generating a replica of a multipath component by applying an adaptive filter to a received signal; a removal means for generating a multipath-component removed signal from which the multipath component has been removed by subtracting the replica from the received signal; a correlation value calculation means for calculating a correlation value between the received signal and the replica; a power value calculation means for calculating a power value of the replica; a determination means for determining whether the replica is the replica of the multipath component based on the correlation value and the power value; and a selection means for outputting the multipath-component removed signal when it is determined that the replica is the replica of the multipath component, and outputting the received signal when it is determined that the replica is not the replica of the multipath component.03-25-2010
20130077668ADAPTIVE FILTER WITH REDUCED COMPUTATIONAL COMPLEXITY - An adaptive filter is disclosed, having a plurality of computation groups, a plurality of computation circuits, a summation circuit, a slicer circuit, an updating circuit, and a control circuit. Each computation group corresponds to an equalization parameter and has a plurality of memory cells. When the corresponding equalization parameter of a computation group is greater than a predetermined value, the control circuit configures the computation group and the computation circuit to collaboratively generate an output of the computation group. The summation circuit sums up the outputs of the computation groups to produce a filter output. The slicer circuit generates a slicer output according to the filter output. The updating circuit updates the equalization parameters according to the filter output and the slicer output.03-28-2013
20130039406TWO STAGE ADAPTIVE EQUALIZER FOR A BATCH RECEIVER - A two stage adaptive filter for use in a batch receiver includes an equalizer filter having as inputs an acquired signal representing a batch of data points and an equalizer filter value. The filtered signal is batch processed to produce reference and data symbols, which symbols are input to a residual filter to generate iteratively over the batch an error value. The error value is convolved with the equalizer filter value to produce a new equalizer filter value for use by the equalizer filter when a next batch of data points is processed.02-14-2013
20100046597Adaptive Receive-Side Equalization - An adaptive receiver equalizes incoming data expressed as a series of symbols, the degree of equalization being adjusted by some adaptive control logic. An amplitude detector samples the amplitude of the eye openings of incoming symbols and conveys the resulting measures of eye amplitude to the adaptive control logic. The control logic experiments with different equalization settings while monitoring the resulting eye amplitude to find the equalization setting that provides incoming data eyes of the highest amplitude. A data filter may be included to enable the amplitude detector only in response to particular incoming data patterns.02-25-2010
20090245343MULTIPLEXER BASED TRANSMITTER EQUALIZATION - In general, in one aspect, the disclosure describes a digital signal equalizer that includes a plurality of multiplexers. The number of multiplexers defines resolution of equalization. The plurality of multiplexers are configured in groups. The number of groups is based on number of taps, and the number of multiplexers associated with a particular group is based on equalization range for the group. The multiplexers in each group select a digital value associated with the cursor or a non-cursor tap associated with the group.10-01-2009
20130034143APPARATUS AND METHOD FOR DIGITALLY-CONTROLLED ADAPTIVE EQUALIZER - Apparatus and methods are disclosed, such as those involving a receiver device. One such apparatus includes an equalizer configured to process an input signal transmitted over a channel. The equalizer includes a first node configured to receive the input signal; a second node; and a programmable gain amplifier (PGA) having an adjustable gain. The PGA has an input electrically coupled to the first node, and an output electrically coupled to a third node. The equalizer also includes a high pass filter (HPF) having an input electrically coupled to the third node, and an output electrically coupled to the second node; and a control block configured to adjust one or more of the PGA or the HPF at least partly in response to a PGA output signal from the PGA or an HPF output signal from the HPF.02-07-2013
20130034144SYSTEM AND METHOD OF PREBIAS FOR RAPID POWER AMPLIFIER RESPONSE CORRECTION - A system and method are provided for reducing dynamic EVM of an integrated circuit power amplifier (PA) used for RF communication. In a multistage PA, the largest amplification stage is biased with a high amplitude current pulse upon receipt of a Tx enable, before receipt of the RF signal data burst. The high amplitude current pulse causes a large portion of the total ICQ budget of the multistage PA to pass through the largest amplification stage causing the entire integrated circuit to rapidly approach steady-state operating conditions. A smoothing bias current is applied to the largest amplification stage after the pulse decays to compensate for transient bias current levels while standard bias circuitry is still approaching steady-state temperature.02-07-2013
20100111159DIGITAL TRANSMISSION AND RECEPTION DEVICES FOR TRANSMITTING AND RECEIVING STREAMS, AND PROCESSING METHODS THEREOF - A transmission system to transmit a transport stream (TS) having normal data and additional data, the transmission system including: a stream constructor to generate a TS, and a multiplexer (MUX) to insert information representing the characteristics of additional data in the TS. Therefore, it is possible for a reception system to use the additional data efficiently.05-06-2010
20100111157WIRELESS COMMUNICATION DEVICE, WIRELESS COMMUNICATION METHOD, SIGNAL PROCESSING DEVICE, SIGNAL PROCESSING METHOD, AND COMPUTER PROGRAM - A wireless communication device includes: a channel matrix estimating unit estimating a channel matrix including channel response elements between antennas; a phase error estimating unit estimating a phase error in a received signal on the basis of a decoding result of encoded and transmitted information symbols of a preamble of a received packet; and a waveform equalizing unit equalizing a waveform of data symbols of the received packet using the channel matrix. Original channel response elements are derived by removing an error of an estimated channel value due to the phase error estimated by the phase error estimating unit from the channel response elements of the channel matrix supplied from the channel matrix estimating unit, and the waveform equalizing unit equalizes the waveform of the data symbols using the channel matrix including the original channel response elements.05-06-2010
20100103996MANAGING TAP POSITIONS IN A DIGITAL DELAY LINE - This method of reading a plurality of chip sample values at tap positions (04-29-2010
20100103997MMSE EQUALISER - A MMSE equaliser taking into account delays in the reception of signals from plural users. Time delays in reception of signals from plural users may be known or can be measured or estimated and can be used to for the basis for the operation of the equaliser. A low computational complexity version of the equaliser and a regularized equalizer with further reduced complexity for asynchronous reception are also disclosed.04-29-2010
20100040131Transmit Equalizer Compensation for Probe Receivers - Transmit equalization over high speed digital communication paths may be compensated in a receiver for a probe on that path. In one example, a probe input provides a signal from an electronic communications path, the signal having been processed by a transmit equalizer. A filter circuit processes the signal to compensate for the transmit equalizer, and a decoder decodes the processed signal and produces an output for use by test equipment.02-18-2010
20100040130RECEIVER CIRCUIT - A first phase adjustment circuit adjusts phases of a data decision clock signal and a first boundary decision clock signal according to a phase adjustment amount based on an output signal of a data decision circuit and an output signal of a first boundary decision circuit. A second phase adjustment circuit adjusts a phase of a second boundary decision clock signal according to a result of adding the phase adjustment amount and a phase adjustment amount offset. An adaptive equalization control circuit adjusts an equalization coefficient of an equalization circuit according to a data width of an output signal of the equalization circuit based on a logical comparison result between the output signal of the data decision circuit and an output signal of a second boundary decision circuit when the phase adjustment amount offset is changed.02-18-2010
20100040127CIRCUIT CONFIGURATION FOR DATA COMBINING - A receiving end apparatus disposes a spatial data combining circuit at symbol level and disposes an HARQ data combining circuit and/or the repetition data combining circuit at bit level. The spatial data combining is performed before the de-mapping, while the de-repetition and/or the HARQ chase combining are performed after the de-mapping. This apparatus configuration can significantly reduce the buffer size and the computation complexity required so the overall performance is therefore improved.02-18-2010
20100040126Arrangement for adaptive bit recovery - The present invention relates to an arrangement for adaptive bit recovery, and to an apparatus for reading from and/or writing to recording media using such arrangement. According to the invention, an arrangement for adaptive bit recovery including an adaptive equalizer and an adaptive partial response maximum likelihood detector further includes an overflow control block for the adaptive equalizer for monitoring one or more of the adaptation coefficients and/or a state violation checker for monitoring the allowed states and indicating state violations as well as and a noise detector for detecting larger deviations of the target values.02-18-2010
20080219342CHANNEL EQUALIZATION WITH NON-COMMON MIDAMBLE ALLOCATION IN 3GPP TD-CDMA SYSTEMS - Systems and methodologies are described that facilitate implementing a linear adaptive equalizer receiver on the downlink link of a UMTS TDD wireless communication system. A reference signal can be generated based on multiple non-common midamble sequences in a time slot of a received transmission. Traffic-to-pilot ratios for channel codes in the time slot can be generated, and relative strengths of channel codes associated with specific midambles can be determined to weight the midamble. A plurality of the weighted midambles can then be utilized to generate a reference signal to train the equalizer, which can facilitate utilization of total aggregate midamble energy rather than midamble energy associated with a single midamble in the signal.09-11-2008
20100142608TRANSMITTING/RECEIVING SYSTEM AND METHOD OF PROCESSING BROADCAST SIGNAL IN TRANSMITTING/RECEIVING SYSTEM - A receiving system and a method of processing broadcast signal are disclosed herein. The receiving system includes a signal receiving unit, a known sequence detector, a channel equalizer, a block decoder, and an error correction unit. The signal receiving unit receives a broadcast signal, which includes mobile service data and a data group including multiple known data sequences. The known sequence detector detects the multiple of known data sequences from the broadcast signal. The channel equalizer repeats a process of updating equalization coefficients and filtering as many times as a pre-determined number of iterations, based upon the detected known data sequences, so as to converge the equalization coefficient. Then, the channel equalizer interpolates or extrapolates using the converged equalization coefficients, thereby channel-equalizing the mobile service data. The block decoder performs turbo-decoding in block units on the channel-equalized mobile service data. And, the error correction unit performs error correction decoding on the decoded mobile service data, thereby correcting an error occurred in the mobile service data.06-10-2010
20090274206ADAPTIVE DATA RECOVERY SYSTEM WITH INPUT SIGNAL EQUALIZATION - Data receivers often include equalizers for operating on received signals. The equalizers often have a plurality of taps, with signals from each tap weighted based on tap settings or values. The tap settings may be set based on bit error rates of data output from the equalizer. In some embodiments data output from the equalizer is split into two signals, and the two signals are processed to indicate a data eye of the data output from the equalizer. Preferred tap settings may be determined by setting tap settings to different values and using tap settings expected to maximize the data eye. This may be performed separately for different bit settings in an attempt to reduce effects of inter-signal interference.11-05-2009
20100329324METHODS AND APPARATUS FOR QUALIFICATION OF UPDATE OF CLOCK RECOVERY AND EQUALIZATION - Methods and apparatus are provided for CDR and equalization update qualification. A block of received data comprising a plurality of multiple tone patterns is processed. Equalization adaptation and/or updates to a timing recovery process can be selectively disabled if one or more of the multiple tone patterns exceed a corresponding predefined threshold.12-30-2010
20100329323DATA RECEIVER AND METHOD FOR ADJUSTING THE SAME - A data receiver and a method for adjusting the same are provided. The data receiver has an equalizer, a clock data recovery unit, an equalizer controller, and a decoder. The equalizer compensates incoming signal according to a configuration, and outputs corrected signal. The CDR unit uses a clock to sample the corrected signal from the equalizer and generates phase information of the clock. The decoder decodes the raw data. Each cycle of the clock is divided into a plurality of phases, and the phase information indicates the one of the phases that the corrected signal sampled therein. In a testing mode, the equalizer controller applies a plurality of setup values to the configuration individually and records the phase information for tuning the configuration. Therefore, the accuracy of the equalizer is improved and the good signal quality is obtained.12-30-2010
20130089132RECEIVER AND METHOD FOR TWO-STAGE EQUALIZATION WITH SEQUENTIAL SEARCH - A receiver and method are described herein that address inter-symbol interference in a received signal by using a two-stage equalizer which includes a first demodulation stage that processes the received signal and produces initial symbol decisions, and a non-linear equalization second stage that uses the received signal to perform a sequential search in an attempt to improve upon the initial symbol decisions where if able to improve upon the initial symbol decisions then an output sequence is obtained from the sequential search and if not able to improve upon the sequence metric threshold then the output sequence is the initial symbol decisions.04-11-2013
20090323796Radio communication method and device in single-carrier transmission system - A radio communication device for receiving a single-carrier signal transmitted in a partial spectrum of Nyquist frequency band, includes: an interference eliminator for eliminating interference from a received signal by spectrum reproduction of non-transmitted spectra using a symbol replica, to output an interference eliminated signal, wherein the interference includes intersymbol interference which is caused by symbols which are more than a predetermined distance away from a decision symbol point; a symbol sequence estimator for estimating a transmission symbol sequence by separating nearby intersymbol interference within the predetermined distance of the decision symbol point based on the interference eliminated signal, to output a decision signal; and a replica generator for generating the symbol replica from decoding result of the decision signal, wherein the symbol replica is fed back to the frequency-domain interference eliminator.12-31-2009
20090304065TRANSMITTING/RECEIVING SYSTEM AND METHOD OF PROCESSING BROADCAST SIGNAL IN TRANSMITTING/RECEIVING SYSTEM - A receiving system and a method of processing data are disclosed herein. The receiving system a signal receiving unit, a known sequence detector, a first equalization unit, a second equalization unit, a block decoder, and an error correction unit. The signal receiving unit receives a broadcast signal including a data group multiplexed mobile service data with a plurality of known data sequences. The known sequence detector detects known data sequences from the broadcast signal. The first equalization unit updates an equalization coefficient by using the known data sequence during the known data section, thereby primarily channel-equalizing the known data sequence. The second equalization unit interpolates or extrapolates a converging equalization coefficient, thereby secondarily channel-equalizing the mobile service data, when the equalization coefficient converge. The block decoder performs turbo-decoding on the channel-equalized mobile service data in block units. And, the error correction unit performs error correction decoder on the decoded mobile service data, thereby correcting errors generated in the mobile service data.12-10-2009
20090304064ADAPTIVE EQUALIZER AND METHOD THEREOF - The present invention relates to an adaptive equalizer and an adaptive equalizing method. The adaptive equalizer comprises an adaptive equalizing unit, for adaptively equalizing an inputted signal to output the equalized signal; a coefficient updating unit, for updating a coefficient of a filter of the adaptive equalizing unit; a switching unit, connected between the coefficient updating unit and the adaptive equalizing unit, wherein when the switching unit is on, the coefficient updating unit is capable of updating the coefficient of the adaptive equalizing unit, and when the switching unit is off, the coefficient updating unit is incapable of updating the coefficient of the adaptive equalizing unit; and a monitoring device, for controlling on or off of the switching unit in accordance with a down sampling phase of the inputted signal or a down sampling phase of the equalized signal.12-10-2009
20090304063EQUALIZER BASED RECEIVER OPERATION METHOD AND APPARATUS IN A MOBILE COMMUNICATION SYSTEM - An equalizer based receiver operation method and apparatus in a mobile communication system are provided. The method includes estimating a channel for a multi path receive signal, analyzing a delay profile of a multi path channel, and selecting a tap position from a plurality of tap positions of an equalizer depending on the analyzed delay profile.12-10-2009
20090304062DTMB-based carrier mode detection system and receiving system having the same - A Digital Terrestrial Multimedia Broadcasting (DTMB)-based carrier mode detection system includes first and second TPS decoders, first and second carrier calculators and a determinator. The first and second TPS decoders respectively receive N12-10-2009
20090092180EQUALIZER CIRCUITRY FOR MITIGATING PRE-CURSOR AND POST-CURSOR INTERSYMBOL INTERFERENCE - One or more embodiments of the invention comprise a continuous-time equalizer (CTE) for reducing both pre-cursor and post-cursor intersymbol interference (ISI) from data received from a communication channel. One such equalizer comprises two independent stages that process the input signal in parallel. One stage subtracts a scaled version of the derivative of the input signal from a scaled version of the input signal to reduce pre-cursor ISI from the input signal. The other stage adds a scaled version of the derivative of the input signal to a scaled version of the input signal to reduce post-cursor ISI from the input signal. The outputs from the two stages are then multiplied to arrive at an output signal in which both pre- and post-cursor ISI is minimized. Because the scalars used in each of the stages are independent, each can be adjusted for greater manipulation of the ISI-reduced signal.04-09-2009
20130070834METHOD AND APPARATUS FOR SINGLE BURST EQUALIZATION OF SINGLE CARRIER SIGNALS IN BROADBAND WIRELESS ACCESS SYSTEMS - A receiver implementing a single carrier single burst equalization (SC-SBE) method is capable of achieving near optimal reception of individual single carrier RF bursts by making an accurate estimate of the burst's propagation channel impulse response (CIR). The SC-SBE method uses a CIR based coefficient computation process to obtain filter coefficients for a minimum mean square error decision feedback equalizer (MMSE-DFE). The MMSE-DFE filter computation process computes a sufficiently large number of coefficients for the DFE filters, i.e., the feed forward filter (FFF) and feedback filter (FBF), so that each filter spans the maximum anticipated length of the CIR. In order to implement the filters efficiently, a coefficient selection process eliminates less significant computed FFF and FBF coefficients. The resulting FFF and FBF are sparse filters in that most of the taps in the filter delay lines do not have a filter coefficient.03-21-2013
20100260252Method and System for Cluster Processing Using Conjugate Gradient-Based MMSE Equalizer and Multiple Transmit and/or Receive Antennas for HSDPA, STTD, Closed-Loop and Normal Mode - A system and method for processing signals are disclosed. The method may include performing by one or more processors and/or circuits in a wireless device that includes a plurality of transmit and/or receive antennas for one or more of HSDPA, space-time transmit diversity (STTD), Closed Loop, Normal Mode and spatial multiplexing, the one or more processors and/or circuits comprising a minimum mean square error (MMSE) equalizer, generating a plurality of chip-rate synchronously sampled signals utilizing a plurality of received clusters. At least a portion of said generated plurality of chip-rate synchronously sampled signals may be simultaneously equalized in time domain and in spatial domain, based on a plurality of weight values calculated for the plurality of received clusters. The plurality of weight values may be iteratively computed utilizing a time-based adaptation method.10-14-2010
20110038407Equalizer receiver in a mobile communication system and method therefor - A method for receiving a signal using an equalizer receiver in a mobile communication system includes matched-filtering a signal received via an antenna. The method also includes generating different phase information for a serving cell and one or more other cells. The method further includes generating Pseudo-random Noise (PN) codes for the cells based on the phase information; estimating channel estimation values for the cells using the PN codes and the filtered signal; modeling random sequences similar in statistical property to signals transmitted from the cells using the channel estimation values, and generating a filter coefficient using the modeled random sequences; and equalizing the filtered signal using the filter coefficient. By doing so, the receiver's channel estimation performance and equalizer adaptation performance may be maximized.02-17-2011
20110058595Method and Apparatus for Detecting In-band Interference in a Data Communications Modem - A method and apparatus for detection and analysis of interference and noise in a received signal within a bandwidth of a predetermined communication channel. A receiver receives a modulated signal and generates a demodulated digital baseband signal. A digital quadrature demodulator receives the digital baseband data signal and demodulates the digital baseband data signal to generate complex digital signal soft-symbol decisions at its output at the received symbol rate. A processor interface in communication with the digital quadrature demodulator and the controller transfers data between the digital quadrature demodulator and the controller. The controller reconstructs a transmitted signal from the transferred data and subtracts the transmitted signal from the modulated signal to generate a third signal representative of noise and interference underlying the transmitted signal within a predetermined communications channel containing the transmitted signal. The modulated and third signals are displayed on a computer screen or a printout for analytical purposes.03-10-2011
20130058391Timing Recovery Module and Timing Recovery Method - The present invention discloses a timing recovery module of a receiver of a communication system. The timing recovery module includes a timing error calculating unit, for calculating a timing error according to an output signal of an equalizer of the receiver; and a multiplexer, for receiving the timing error, a specific negative timing error and a specific positive timing error, and outputting one of the timing error, the specific negative timing error and the specific positive timing error as a timing adjustment value according to a main tape coefficient, a most negatively adjacent tape coefficient and a most positively adjacent tape coefficient of the equalizer.03-07-2013
20110013687LOW COMPLEXITY FINE TIMING SYNCHRONIZATION METHOD AND SYSTEM FOR STIMI - A method and system of fine timing synchronization for an OFDM signal. The OFDM signal is coarse timing synchronized, generating a synchronization sequence and a CFR (Channel Frequency Response). The synchronization sequence is removed. A correlation coefficient of the correlation between the CFR applied to a number of carriers and the number of carriers with different window shifts is calculated. The largest window shift corresponding to a downsampling factor is indicated by the lowest correlation coefficient greater than a threshold. The CFR is downsampled by the downsampling factor, and an inverse FFT is performed on the downsampled CFR with a reduced number of calculations reduced by the downsampling factor, transforming the CFR into a CIR. A fine timing synchronization position is determined from the CIR and is utilized by an FFT unit within an OFDM receiver to accurately receive OFDM symbols of the OFDM signal. Application to Satellite Terrestrial interactive Multi-service Infrastructure (STiMi)01-20-2011
20110013686SYSTEMS AND METHODS FOR IMPROVING CHANNEL ESTIMATION - A method for improving channel estimation in a wireless communication system is disclosed. A wireless signal that includes a plurality of multipath components is received. N channel estimates are then obtained, where N is any positive integer greater than one. Each channel estimate of the N channel estimates corresponds to a different multipath component of the plurality of multipath components. The effects of interference between the plurality of multipath components on the N channel estimates is then reduced.01-20-2011
20110013685Channel and Equalization Coefficient Based Timing Recovery - A module and method for channel estimate and equalization coefficient based timing recovery comprises a timing estimation module, two channel estimation modules communicably coupled to the timing estimation module, an equalization coefficient computation module communicably coupled to the timing estimation module and one of the channel estimation modules, a conversion module communicably coupled to the timing estimation module and to the two channel estimation modules, and a pulse shaping filter communicably coupled to the conversion module, wherein: the pulse shaping filter receives a signal and outputs a filtered signal, the conversion module receives the filtered signal and outputs two 1/T rate signal streams, a sample time=t stream and a sample time=t−Ω stream where Ω is small compared to T, with each stream going to one of the two channel estimation modules, the channel estimation modules each output a 1/T Channel Impulse Response (CIR) estimate to the timing estimation module, the equalization coefficient computation module receives the CIR estimate from the channel estimation module that receives the sample time=t signal stream and outputs the equalization coefficients to the timing estimation module, and the timing estimation module outputs a timing offset parameter to the conversion module, wherein the timing offset parameter is used in conjunction with the output of the pulse shaping filter to provide two 1/T rate signal streams.01-20-2011
20110013684Channel estimates in a SIC receiver for a multi-transmitter array transmission scheme - In a receiver first stage, received signals are equalized using first stage channel estimates, a first data stream is separated from a second data stream; and interference on the first data stream is re-generated by filtering the decoded first data stream (after decoding) using the first stage channel estimates. Second stage channel estimates are calculated using the first stage channel estimates and gain derived from generating the interference, and the interference is subtracted from the received signals. In the receiver second stage, the signals from which the interference was subtracted are equalized using the second stage channel estimates, the second stream of data is decoded; and the decoded first data stream and the decoded second data stream are output. One embodiment gets channel estimates for each stage from the received signal and regenerates pilot interference; the other calculates updated channel estimates from the first stage for use in the second stage.01-20-2011
20090268800DEMODULATION CIRCUIT, DEMODULATION METHOD, PROGRAM, AND RECEPTION APPARATUS - A demodulation circuit including: a first error calculation section configured to calculate a first error in accordance with a blind method; a second error calculation section configured to calculate a second error in accordance with a DD method; an update section configured to update filter coefficients for first and second filters based on the first or second error, the first filter filtering an input signal to generate a first signal, the second filter filtering a signal representing a hard decision value for a post-equalization signal to generate a second signal; a control section configured to, in the case where the update section is updating the filter coefficients based on the second error, controlling the filter coefficients to be updated based on the first error, when the degree of the second error has exceeded a first threshold; and a generation section configured to generate the post-equalization signal based on the first and second signals.10-29-2009
20090268799EQUALIZATION SYSTEM AND METHOD THEREOF - An equalization system used in a communication receiver has multiple equalization stages. A front equalizer supplies equalization output to a feed back filter in a rear equalizer to speed initialization of the rear equalizer. In addition, the rear equalizer supplies decision output to the front equalizer to estimate errors so as to provide more accurate tap coefficient adjustments. Both the front equalizer and the rear equalizer can be implemented with iterative equalizers to further enhance equalization performance.10-29-2009
20130215953Measurement of intermodulation products of digital signals - Measurement of intermodulation products of digital signals. One or more devices, within a communication system, having and analog to digital converter (ADC) with a sufficiently wide frequency response as to capture not only a signal of interest, but many other signals simultaneously, allows for appropriate signal processing of such captured samples to identify one or more intermodulation products that may exist as a function of the relationship of one or more frequencies. For example, composite second order (CSO) or composite triple beat (CTB), or even higher ordered signals, may occur within various communication systems. These effects may be caused by any of a number of sources including nonlinearities in the system, such as affects associated with laser clipping, amplifier compression, corroded connectors, etc. Appropriate processing is performed determine the existences of such intermodulation product signals, and, if desired, subsequent signal processing and/or fixing of such effects therein is performed.08-22-2013
20090067485WAVEFORM EQUALIZING DEVICE - A waveform equalizing device for performing high-precision waveform equalization for an input signal and outputting the result as an output signal, includes: a FIR filter for performing convolution operation between the input signal and a plurality of tap coefficients; first and second slicers at least one of which makes decision on the value of the output signal; a first delay device for imparting a delay to the output of the second slicer; an IIR filter; and an addition section for summing the output of the FIR filter and the output of the IIR filter and outputting the sum as the output signal. The IIR filter includes first and second delay portions for respectively receiving the outputs of the first slicer and the first delay device and imparting delays, and performs convolution operation between the signal received by the first delay portion and tap coefficients for the first delay portion and between the signal received by the second delay portion and tap coefficients for the second delay portion.03-12-2009
20090060019EQUALIZER SYSTEM AND FILTERING METHOD - An equalizer system comprises a gain adjuster and a filter system. The gain adjuster provides a plurality of gain settings. The filter system is coupled to the gain adjuster and filters an input signal to output a filtered signal in response to the gain settings. The filter system comprises at least one high shelving filter with a first transfer function and at least one low shelving filter with a second transfer function. The reciprocal of the first transfer function is equal to the second transfer function.03-05-2009
20090262795Adaptive equalizer tap stepsize - An apparatus comprises an adaptive filter having groups of taps, each group comprising at least one tap having an associated tap value; and a controller for selecting a scaling factor for at least one group of taps as a function of tap values of the group. The controller further adjusts an error value as a function of the selected scaling factor. The adaptive filter adapts tap values of the at least one group of taps as a function of the adjusted error value.10-22-2009
20100142606Transmission line loss compensation circuit and transmission line loss compensation method - A transmission line loss compensation circuit and transmission line loss compensation method is provided. The transmission line loss compensation circuit includes a linear equalizer that compensates for a transmission line loss of high frequency components, a high-pass filter that extracts high frequency components from an output of the linear equalizer, a peak detector that compares the peak voltage of a high-pass filter output to first and second reference voltages, and a control circuit that controls the compensation intensity of the linear equalizer based on the detection results of the peak detector so that the peak voltage becomes an intermediate voltage between the first reference voltage and the second reference voltage.06-10-2010
20090232195CLOCK DATA RESTORING DEVICE - The clock data restoration device 09-17-2009
20090268801Limiter Based Analog Demodulator - A phase detector includes a decimator to decimate a digitized in-phase signal and a digitized quadrature signal to N times a symbol rate, where N is an integer greater than one. A burst detector to detect bursts in an output of the decimator. A carrier offset block to determine an offset angle based on an output of the burst detector. A rotator to generate a rotated signal by rotating the output of the decimator based on the offset angle determined by the carrier offset block. An equalizer to perform coherent demodulation of the rotated signal.10-29-2009
20090010320Fractional-Rate Decision Feedback Equalization Useful in a Data Transmission System - Decision feedback equalization (DFE) circuits are disclosed for use with fractional-rate clocks of lesser frequency than the data signal. For example, a one-half-rate clocked DFE circuit utilizes two input data paths, which are respectively activated on rising and falling edges of an associated half-rate clock. Each of the input data paths has a pair of comparators with differing reference voltage levels. The comparators in each input data path output to a multiplexer, which picks between the two comparator outputs depending on the logic level of the previously received bit. The output of each input data path is sent as a control input to the multiplexer of the other data path. Thus, the results from previously-detected bits affect which comparator's output is passed to the output of the circuit, even though the synchronizing clock is half the frequency of the data. A quarter-rate DFE circuit is also disclosed which operates similarly.01-08-2009
20100086018Channel Estimator and Channel Estimation Method - The invention discloses a double-estimation channel estimator for calculating a plurality of accurate channel responses from a plurality of synchronization signals, comprising a first channel estimator, for calculating a plurality of first channel responses at all time points over all sub-channels according to a plurality of pilot signals and the synchronization signals; a first equalizer, for calculating a plurality of first equalization signals at all the time points over all the sub-channels according to the first channel responses and the synchronization signals; a second channel estimator, for calculating a plurality of second responses at all the time points over all the sub-channels according to the first equalization signals and the synchronization signals; and a calculation module, for calculating a plurality of third channel responses at all the time points over all the sub-channels according to the first channel responses and the second channel responses.04-08-2010
20120236924Spatial and Temporal Pre-Equalization - The present invention describes a channel equalizer and a method for channel equalization in a receiver in a multi-user communication system. The method comprises the steps of receiving a signal with at least two antennas to produce at least two antenna input streams, measuring the temporal of each antenna input stream and the spatial correlation between the antenna input streams, determining a user-independent pre-equalization filter from the temporal and spatial correlation, filtering the antenna input streams with the pre-equalization filter, and finally inputting the filtered signal to a user-dependent receiver configured to detect the received data symbols of a given user.09-20-2012
20120236923Method and Device for Compensating Frequency Response of a Filter Unit in Remote Radio Unit in Real Time - A method for compensating frequency response of a filter unit in remote radio unit in real time, said remote radio unit comprises filter unit equalizer, transmitter observation receiver and antenna calibration receiver, said method comprising the steps of: receiving input signal of said filter unit by transmitter observation receiver; receiving output signal of said filter unit by antenna calibration receiver; calculating coefficients of filter unit equalizer in real time based on said input signal and said output signal; updating said filter unit equalizer based on said calculated coefficients in order to compensate frequency response of said filter unit. A device to carry out the above method, remote radio unit comprising said device and a telecommunication system comprising said remote radio unit are also provided.09-20-2012
20120236922DIGITAL BROADCASTING TRANSMITTER, DIGITAL BROADCASTING RECEIVER, AND METHOD FOR COMPOSING AND PROCESSING STREAMS THEREOF - Disclosed is a method of processing a stream of a digital broadcasting receiver. The method comprises: arranging at least one of new mobile data and known data in at least a portion of an existing mobile data region and in at least a portion of a normal data region, in a stream which includes the normal data region and the existing mobile data region; and composing a transmission stream where at least one of the new mobile data and the known data is arranged, and wherein the arranging combines a block of data arranged in the existing mobile data region and a block of the new mobile data in the stream, and performs serially concatenated convolution code (SCCC) coding on the combined blocks.09-20-2012
20130163657OPTIMAL LINEAR EQUALIZER FOR MIMO SYSTEMS WITH HARQ AND/OR REPETITION CODING - Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors based on the same transmitted vector. The symbols of the received signal vectors are combined, forming a combined received signal vector that may be treated as a single received signal vector. The combined received signal vector may be equalized by, for example, a zero-forcing or minimum-mean-squared error equalizer or another suitable linear equalizer. Following equalization, the equalized signal vector may be decoded using a simple, linear decoder.06-27-2013
20120269254CHANNEL ARCHITECTURE WITH MULTIPLE SIGNAL PROCESSING BRANCHES FOR A GIVEN PHYSICAL CHANNEL - A communication system includes a physical communication channel. A signal is transmitted across the communication channel from a transmit end of the channel to a receive end of the channel. A plurality of processing branches process the signal at the receive end of the communication channel. This reduces complexity of the receive channel, without reducing a bandwidth of the given communication channel, and without comprising performance.10-25-2012
20080267276CHANNEL ESTIMATION ENHANCED LMS EQUALIZER - The present invention is related to an enhanced equalizer using channel estimation. A scaled version of a channel estimate is used as an expected average behavior of the product of a transmitted signal and a received signal to implement Griffith algorithm. The present invention also uses advance or prediction of a channel estimate to overcome the lag problem inherent in a least means square (LMS) algorithm in a time varying channel. Therefore, the present invention enables the use of a small step size while attaining the same tracking capability with a large step size. A channel estimate at some time in the future is used for updating equalizer filter tap coefficients. This may be performed with a prediction filter. Alternatively, a delay may be introduced in the input data to the filter tap coefficient generator, which makes a channel estimate look like a prediction to the filter tap coefficient generator.10-30-2008
20120300830EQUALISER FOR WIRELESS RECEIVERS WITH NORMALISED COEFFICIENTS - A method, receiver and program for equalising a radio signal comprising a sequence of data samples multiplexed with a sequence of pilot samples. The method comprises; calculating equaliser coefficients by computing cross-correlations of the received signal and known pilot samples available at the receiver and auto-correlations of the received signal; and equalising the received signal using the calculated coefficients.11-29-2012
20100027609EQUALIZATION FILTER AND DISTORTION COMPENSATING METHOD - An equalization filter is provided for solving the problem in which there is a limited range in which compensated for distortion of a transmission signal can be made.02-04-2010
20100027605OFF-TRACK AWARE EQUALIZER DESIGN FOR BIT-PATTERNED MEDIA - An equalizer employed in conjunction with bit-patterned media (BPM) is designed to take advantage of a common topology associated with BPM in which each data track is comprised of a plurality of sub-tracks. The equalizer-target filter pair is designed as multiple-input/multiple-output (MIMO) system, in which the readback signal is divided into readback signals associated with each sub-track. The MIMO equalizer takes into account differences in the channel response associated with each sub-track. A detector is configured to receive a plurality of equalized inputs provided by the MIMO equalizer, wherein the detector generates in response estimates of the user data stored on each of the plurality of sub-tracks.02-04-2010
20090067483Efficient adaptive equalizer implementation - The present invention is related to the digital implementation of adaptive equalizers for high-speed communication systems, using finite precision arithmetic, for example, as implemented in a silicon ASIC.03-12-2009
20110032978Receiver and Method for Adjusting Adaptive Equalizer of Receiver - A receiver includes an adaptive equalizer, a power detecting unit and an adjusting unit. The adaptive equalizer is for receiving a signal and generating an equalized signal. The power detecting unit, coupled to the adaptive equalizer, is for detecting the strength of the equalized signal during a first period to generate a first strength signal, and detecting the strength of the equalized signal during a second period to generate a second strength signal. The adjusting unit, coupled to the power detecting unit and the adaptive equalizer, is for adjusting the compensation strength for the adaptive equalizer according to the first and second strength signals.02-10-2011
20080240221COMMUNICATION SIGNAL SYMBOL TIMING ERROR DETECTION AND RECOVERY - Communication signal symbol timing error detection and recovery apparatus and techniques are disclosed. A communication signal that includes symbols is sampled according to receive symbol timing. The samples are band-edge filtered to provide a filtered output signal including band edges of the samples. The filtered output signal is converted to baseband, and a phase error of the receive symbol timing is calculated based on the down converted baseband signal. The communication signal may include symbols associated with quadrature channels, in which case a respective filtered output signal that includes band edges of samples associated with each quadrature channel may be down converted. The down converted baseband signals may then be separated into upper and lower band-edge signals, which are used to calculate a phase error of the receive symbol timing. The upper and lower band-edge signals may also be used for other purposes, such as slope equalization and/or carrier synchronization.10-02-2008
20080219341Space-frequency equalization for oversampled received signals - Techniques for performing space-frequency equalization and spatial equalization in the frequency domain are described. Space-frequency equalization combines signal components across both space and frequency dimensions whereas spatial equalization combines signal components across space. A receiver obtains input symbols for multiple (M) signal copies from multiple (R) receive antennas and multiple (C) times oversampling, where M is equal to R times C. For space-frequency equalization, the receiver derives equalizer coefficients for the M signal copies, e.g., based on MMSE criterion, filters, the input symbols for the M signal copies with the equalizer coefficients, and combines the filtered symbols for the M signal copies to obtain output symbols. Space-frequency equalization may be used for some frequency bins and spatial equalization may be used for other frequency bins to reduce complexity.09-11-2008
20110129010RECEIVING EQUALIZATION DEVICE IN COMMUNICATION SYSTEM AND RECEIVING EQUALIZATION METHOD - Disclosed are a receiving equalization device and a method thereof, the receiving equalization device including a subtracter to output a first output signal, an eye monitor block to obtain a sampling timing by using the output first signal, and a slicer to generate a sampling signal by sampling the first output signal based on the sampling timing, and to return the generated sampling signal to the subtracter via a feedback filter or an algorithm determining block.06-02-2011
20110299584Equalization system - An equalization system includes an adjustable equalization unit, a common-mode feedback unit connected with the equalization unit, a current balance driving unit connected with the feedback and equalization units, a first high-pass filter unit connected with the equalization unit, a second high-pass filter unit connected with the driving unit, a first low-pass filter unit connected with the equalization unit, a second low-pass filter unit connected with the driving unit, a first energy detection unit connected with two high-pass filter units, a second energy detection unit connected with two low-pass filter units, a first analog-to-digital converter unit connected with the first energy detection unit, a second analog-to-digital converter unit connected with the second energy detection unit and a state decision unit connected with two analog-to-digital converter units outputs a control signal for adjusting the equalization unit. It improves the signal quality of the receiver of the high-speed signal transmission system.12-08-2011
20120082201DATA DETECTING DEVICE, REPRODUCING DEVICE, AND DATA DETECTING METHOD - A data detecting device includes a multi-input adaptive equalizer, a binarizing unit, and an equalization error calculating unit. The multi-input adaptive equalizer includes a plurality of adaptive equalizers and outputs a reproduction information signal from a target track and a reproduction information signal from a close track close to the target track as equalization signals by calculating outputs of the adaptive equalizers, the reproduction information signals being input to the adaptive equalizers, respectively as reproduction information signals. The binarizing unit obtains binarized data by performing a binarization process on the equalization signals. The equalization error calculating unit obtains an equalization error from an equalization target signal obtained from the binarization result of the binarizing unit and an equalization signal output from the multi-input adaptive equalizer, and supplies the equalization error as a tap coefficient control signal for equalization to the adaptive equalizers.04-05-2012
20110299583RECEIVING DEVICE AND RECEIVING METHOD - To optimize an adaptive equalizer with a simple controlling circuit, the receiving device includes a number counting part counting, in a range of detection having a predetermined width, a sampling result corresponding to the input signal being shaped by an equalizer circuit at a determination timing indicated by a clock signal obtained in a CDR circuit, a zone scanning part scanning the range of detection in a scanning zone including a variation range of the input signal; a coefficient altering part altering an equalizer coefficient set to the equalizer circuit; a peak detecting part detecting a peak value of a number of appearances of the sampling result according to alteration of the equalizer coefficient and scanning of the range of detection; and a coefficient specifying part specifying the equalizer coefficient being used when detecting the peak value in the peak detecting part as a first coefficient.12-08-2011
20110292991INFORMATION PROCESSING DEVICE, RECEIVING METHOD, AND WIRELESS COMMUNICATION SYSTEM - There is provided an information processing device, including a preamble detection portion, a sync detection portion, a storage portion, a storage control portion, a delay time imparting portion, a bias computation portion, a half sampling portion, an adaptive equalization portion an equalization performance determination portion that compares equalization errors for each one of the sync portion candidates for which the training equalization has been performed by the adaptive equalization portion, and that sets the candidate position with the least error, and a binary determination portion that decodes the Manchester code into NRZ code by subjecting to binary determination the received signal that has been adaptively equalized by the adaptive equalization portion. The storage control portion reads the received signal from the storage portion based on information about the candidate position with the least error that has been set by the equalization performance determination portion.12-01-2011
20090168864Digital Communication System, Indoor Unit, and Outdoor Unit - A digital communication system, an indoor unit, and an outdoor unit in which characteristic variation due to temperature is small are provided. The digital communication system comprises an IDU 07-02-2009
20090316767Detecting Residual ISI Components Using Two Data Patterns - In one embodiment, a method includes accessing an input signal from a receiver that includes a series of bits and further comprising residual boundary intersymbol interference (ISI). The method includes identifying a first bit sequence in the input signal and identifying a second bit sequence in the input signal that differs from the first bit sequence with respect to one or more data values of one or more bits in the first and second bit sequences corresponding to particular residual boundary ISI for measurement. The method includes determining a difference between first boundary error in the first bit sequence and second boundary error in the second bit sequence and measuring the particular residual boundary ISI by the difference for use in adaptive equalizer control.12-24-2009
20080232452Parameterized filters and signaling techniques - Filter taps for filters are specified by filter coefficient parameters. The filter taps are greater in number than the coefficient parameters from which the filter taps are calculated. For example, two coefficient parameters are used to specify a four-tap filter. Filter information can be signaled in a bitstream, such as by signaling one or more family parameters for a filter family and, for each filter in a family, signaling one or more filter tap parameters from which filter taps can be derived. Family parameters can include a number of filters parameter, a resolution parameter, a scaling bits parameter, and/or a full integer position filter present parameter that indicates whether or not the filters include an integer position filter. Filter parameters can be signaled and used to determine coefficient parameters from which filter taps are calculated.09-25-2008
20090129456RECEIVER WITH MULTIPLE ANTENNAS AND METHOD OF RECEIVING SIGNALS - Provided are a multiple antenna receiver and a method of receiving a signal. A multiple antenna receiver includes a plurality of antennas to receive a plurality of received symbols, a QR decomposition unit to perform QR decomposition for a channel matrix, a Q-received symbol generator to generate Q-received symbols corresponding to the plurality of antennas, a subtractor to remove a component corresponding to at least one neighbor symbol from a target received symbol corresponding to one of the Q-received symbols, an adder to add a signal component to the target received symbol, a first FDE to perform frequency domain equalization for an output of the subtractor, and a second FDE to perform frequency domain equalization for an output of the adder.05-21-2009
20090196336SIGNAL PROCESSING DEVICE UTILIZED IN COMMUNICATION SYSTEM - The present invention provides a signal processing device. The signal processing device includes a first feed forward equalizing unit, a first data slicing unit, a second feed forward equalizing unit, and a second data slicing unit. The first feed forward equalizing unit is utilized for performing a compensation operation according to a digital input signal so as to generate a first equalized signal. The first data slicing unit is coupled to the first feed forward equalizing unit, and utilized for generating a first output signal according to the first equalized signal. The second feed forward equalizing unit is coupled to the first data slicing unit, and utilized for generating a second equalized signal according to the first equalized signal. The second data slicing unit is coupled to the second feed forward equalizing unit, and utilized for generating a second output signal according to the second equalized signal.08-06-2009
20100054323Adaptive Receive-Side Equalization - An adaptive receiver equalizes incoming data expressed as a series of symbols, the degree of equalization being adjusted by some adaptive control logic. An amplitude detector samples the amplitude of the eye openings of incoming symbols and conveys the resulting measures of eye amplitude to the adaptive control logic. The control logic experiments with different equalization settings while monitoring the resulting eye amplitude to find the equalization setting that provides incoming data eyes of the highest amplitude. A data filter may be included to enable the amplitude detector only in response to particular incoming data patterns.03-04-2010
20100034253Double Equalizer for Multi-Path Rejection - An apparatus for improved reception of a signal is described. The apparatus includes an equalizer that has at least two cascaded maximum-likelihood detectors and an adjustable delay unit. The equalizer and the adjustable delay unit are configured for adaptation in accordance with one or more multi-path signals in a communication channel that conveys the signal.02-11-2010
20100027608Scrambled multicarrier transmission - Signals (typically in the form of OFDM signals) are transmitted between one or more transmitting antennas and one or more receiving antennas. The signals transmitted are subject to addition of a guard interval before scrambling in the time domain, while the signals received are subject to removal of the guard interval after scrambling in the time domain. Preferably time-scrambling of the OFDM signal being transmitted occurs after IFFT processing and guard interval insertion, while time de-scrambling of the signal being received occurs before both guard interval removal and FFT processing. Optionally, unscrambled pilot symbols (e.g. in the form of a training sequence), can be present at regular intervals inside the signal structure. At the receiver, equalization is carried out preferably in the frequency domain.02-04-2010
20100027606Adaptive equalization employing pattern recognition - In described embodiments, an adaptive equalizer employed by a receiver in a communication channel, such as Fibre Channel, employs pattern recognition. When a repeating pattern, such as an IDLE or ARBFF pattern, is employed by a standard to, for example, maintain a communication link, an equalizer of the receiver might adaptively set its equalizer parameters based on characteristics of the signal energy of the repeating pattern rather than adaptively set its equalizer parameters based on characteristics of the signal energy of generally random user data carried on the link. Pattern recognition by the receiver allows for maintaining adaptive equalizer parameters at settings preferred for data detection of the typical random data, improving data detection performance of the receiver when the channel transitions from a preset or synchronization repeating pattern to a user random data pattern.02-04-2010
20090190647DISTORTION COMPENSATING APPARATUS AND POWER AMPLIFIER APPARATUS - A distortion compensating apparatus has an adaptive distortion compensating unit to compensate nonlinear distortion by controlling an input signal of a nonlinear distortion circuit by using an adaptive algorithm so as to reduce an error between a reference signal and a feedback signal from the nonlinear distortion circuit; and an adaptive equalizer connected between the adaptive distortion compensating unit and the nonlinear distortion circuit or provided in front of the adaptive distortion compensating unit. The adaptive equalizer includes a digital filter to form an amplitude characteristic and a phase characteristic of the input signal on the basis of a filter coefficient group that is set to the digital filter; a memory to hold in advance the filter coefficient group; and a control unit to control reading of the filter coefficient group from the memory on the basis of the input signal and the feedback signal.07-30-2009
20100091831INTERFERENCE CANCELING MATCHED FILTER (ICMF) AND RELATED METHODS - An interference cancelling matched filter (ICMF) may include an antenna for receiving a signal burst including a training sequence therein, and an adaptive space-time filter connected to the antenna and having settable filter coefficients. The ICMF may further include a channel impulse response estimator for estimating a channel impulse response based upon the training sequence, and a signal blocker operatively connected between the channel impulse response estimator and the adaptive space-time filter so that the filter coefficients thereof are set based upon the training sequence.04-15-2010
20100124268SINGLE-CARRIER/MULTI-CARRIER COMMUNITY RECEIVER AND RELATED SIGNAL PROCESSING METHOD - A single-carrier/multi-carrier community receiver includes a discrete Fourier transform unit, a frequency-domain equalizer, an inverse discrete Fourier transform unit and an inter-symbol interference (ISI) cancellation unit. The discrete Fourier transform unit is utilized for executing a discrete Fourier transform upon a received signal to generate a frequency-domain signal. The frequency-domain equalizer is utilized for executing an equalization operation upon the frequency-domain signal to generate a frequency-domain equalized signal. The inverse discrete Fourier transform unit is utilized for executing an inverse discrete Fourier transform upon the frequency-domain equalized signal to generate a time-domain equalized signal. The ISI cancellation unit is utilized for executing an ISI cancellation operation upon the time-domain equalized signal to generate an ISI-cancelled signal.05-20-2010
20100128772RECEIVER STRUCTURE AND METHOD FOR THE DEMODULATION OF A QUADRATURE-MODULATED SIGNAL - The invention relates to a receiver for a quadrature-modulated signal, which can be divided into an inphase signal (I) and a quadrature signal (Q). The inphase signal (I) is fed to first and third equalizers (EZ05-27-2010
20080240222SYSTEM AND METHOD FOR BALANCING DELAY OF SIGNAL COMMUNICATION PATHS THROUGH WELL VOLTAGE ADJUSTMENT - A method of balancing signal interconnect path delays between an analog domain and a digital domain of an integrated circuit includes applying a test signal to a selected one of a plurality of communication paths between the analog domain and the digital domain. A rising edge delay and a falling edge delay of the test signal is equalized by adjusting a body bias voltage of a delay element configured within the selected communication path. A rising edge delay and a falling edge delay for each of the remaining communication paths is compared with the equalized rising edge delay and falling edge delay of the selected communication path, and a body bias voltage for one or more of a plurality of delay elements configured within each of the remaining communication paths is adjusted until corresponding rising and falling edge delays thereof match the equalized rising edge delay and falling edge delay of the selected communication path.10-02-2008
20100040128Equalizer and Method for Processing a Signal and Communication Receiving System Comprising the Same - A communication receiving system, an equalizer, and a method for mitigating a burst noise effect of a signal are provided. The equalizer is configured to compensate the signal received from a communication channel. The communication receiving system comprises a receiver, the equalizer, and a detection module. The receiver transmits the signal to the equalizer after receiving the signal. The equalizer compensates the signal and adapts its weighting factors by modifying a correction term upon detection of burst noise. Thereby, the burst noise effect of the signal is mitigated, and the probability that the equalizer survives the burst noise condition increases. Thus, the quality of communication systems under burst noise cases may be enhanced under without increasing the complexity of hardware.02-18-2010
20100278227HYBRID SAIC RECEIVER - Systems and methods of receiving data in a communication system are disclosed. The methods include equalizing a plurality of samples to suppress intersymbol interference and provide a first set of detected bits based on a first set of reference bits comprising a training sequence on a first iteration. The methods further include suppressing co-channel interference in the plurality of input samples and provide a set of suppressed samples based on a second set of reference bits comprising the first set of detected bits on a second iteration. The methods further include equalizing the set of suppressed samples to suppress intersymbol interference and provide a second set of detected bits based on the second set of reference bits on the second iteration.11-04-2010
20090310666ADAPTIVE EQUALIZER CIRCUIT - An adaptive equalizer circuit includes an equalizer circuit configured to produce an output data signal in response to an equalizing factor, a data detecting circuit configured to detect a signal level of the output data signal in a given unit time at predetermined timing, a boundary detecting circuit configured to detect a signal level of the output data signal at a timing that is ½ unit time away from the predetermined timing, and a control unit configured to detect, multiple times, a pattern having consecutive data items of a first value followed by a data item of a second value, and to adjust the equalizing factor such that a data detection value and a boundary detection value obtained for the data item of the second value are equal to each other a certain percentage of times, and are different from each other substantially the same percentage of times.12-17-2009
20100124265FOLDING SEQUENTIAL ADAPTIVE EQUALIZER - A folding adaptive equalizer is provided. The equalizer comprises an equalizer core and an automatic gain control loop. The equalizing transfer function of the equalizer core is modulated by one or more gain control signals generated by the automatic gain control loop and by a folding signal generated by the automatic gain control loop. When the folding signal is inactive, an increase in the gain control signals produces an increase in the high-frequency, high-bandwidth gain of the transfer function of the equalizer core. When the folding signal is active, further gain can be applied by decreasing the gain control signals, which produces a frequency-shift in the transfer function of the equalizer core toward lower bandwidth and an increase in the high-frequency, low-bandwidth gain of the transfer function of the equalizer core.05-20-2010
20100124266Method and Device of Frequency Domain Equalization - A method of a frequency-domain equalization to jointly suppress inter-symbol interference (ISI) and data-like co-channel interference (CCI) includes receiving a transmit signal over a channel, generating a vector by sampling and converting the transmit signal to a frequency domain signal; generating an equalized vector by multiplying an equalization matrix to the vector generated by converting; generating an estimate of data vector by inverse converting the equalized vector; and recovering data included in the transmit signal based on the estimate of data vector, wherein the equalization matrix is generated by approximating a frequency domain correlation matrix. Significant computational complexity is reduced than the LMMSE equalization while resulting in almost no performance degradation compared to the LMMSE equalization.05-20-2010
20080260014Apparatus for and Method of Controlling a Feedforward Filter of an Equalizer - A method of synchronizing a feedforward filter (10-23-2008
20100128774SINGLE CARRIER/MULTI CARRIER COMMUNITY RECEIVER - A single carrier/ multi carrier community receiver includes: a first discrete Fourier transform unit, for generating a frequency-domain signal by executing a first discrete Fourier transform on a received signal received via the single carrier/multi carrier; a first frequency-domain equalizer, for generating a first equalized frequency-domain signal by executing a first equalizing process on the frequency-domain signal; an inverse discrete Fourier transform unit, coupled to the first frequency-domain equalizer, for generating a first equalized time-domain signal executing an inverse discrete Fourier transform according to the first equalized frequency-domain signal; a slicer, coupled to the inverse discrete Fourier transform unit, for generating a sliced time-domain signal by executing a slicing process according to the first equalized time-domain signal; and a compensating circuit, for compensating the first equalized frequency-domain signal or the first equalized time-domain signal at least according to the sliced time-domain signal.05-27-2010
20100080279METHOD AND APPARATUS FOR REDUCING INTERFERENCE OF A SIGNAL OVER A PLURALITY OF STAGES - An apparatus for reducing interference of a signal over a plurality of stages includes a processor configured to determine at least two equalizer taps based on at least one of a covariance and a channel impulse response of the signal. The processor is further configured to estimate at least one additional equalizer tap based on the at least two equalizer taps. In addition, the processor is configured to reduce, for each of the plurality of stages, the interference of the signal for that stage using an equalizer tap from either the at least two equalizer taps or the at least one additional equalizer tap, so that the signal for the next stage in the plurality of stages has the reduced interference. A method is also provided for reducing interference of a signal over a plurality of stages.04-01-2010
20120033725SIGNAL PROCESSING SYSTEM AND METHOD FOR CALIBRATING CHANNEL SIGNALS SUPPLIED FROM AN ARRAY OF SENSORS HAVING DIFFERENT OPERATING CHARACTERISTICS - In a signal processing system, a set of channel signals from an array of sensors of different operating characteristics are processed in calibration circuitry that calculates individual average values of the channel signals and calculates an average of the individual average values of channel signals as a reference value. Reciprocal calculators calculate reciprocal values of the individual average values of the channel signals. Scaling circuitry scales the reciprocal values by the reference value to produce a set of amplitude calibration signals and scales the channel signals by the calibration signals respectively. As a result, the channel signals are normalized by their own average values and scaled by the reference value to produce a set of calibrated channel signals.02-09-2012
20090207901DELAY CIRCUIT AND METHOD CAPABLE OF PERFORMING ONLINE CALIBRATION - A delay circuit includes a first reference delay module, a second reference delay module and a first delay module. The first reference delay module delays a reference signal and generates a first reference delayed signal, and the second reference delay module delays the reference signal and generates a second reference delayed signal according to a reference control signal and the first reference delayed signal. The first delay module delays a first input signal and generates a first output signal according to a first control signal and the second reference delayed signal.08-20-2009
20110200089RECEIVER - A receiver receives a reception signal subjected to orthogonal frequency division multiplexing modulation or orthogonal frequency division multiple access modulation. The receiver has: an array antenna for receiving the reception signal; adaptive equalizers provided in each of the plurality of antennas, and reducing advanced or delayed waves having a delay time to a main wave in the reception signal; a spatial diversity combining portion which multiplies output signals of the adaptive equalizers by a weighting coefficient and adds the multiplied signals; a weight control portion generating the weighting coefficient; and an equalizer setting unit which estimates an arrival angle and a delay time for each path of the reception signal, and based on the estimation, decides an interference wave to be eliminated by the adaptive equalizers among interference waves, and sets in the adaptive equalizers the delay time of the decided interference wave.08-18-2011
20100086017Automatic calibration in high-speed serial interface receiver circuitry - Circuitry for receiving a serial data signal (e.g., a high-speed serial data signal) includes adjustable equalizer circuitry for producing an equalized version of the serial data signal. The equalizer circuitry may include controllably variable DC gain and controllably variable AC gain. The circuitry may further include eye height and eye width monitor circuitry for respectively producing first and second output signals indicative of the height and width of the eye of the equalized version. The first output signal may be used in control of the DC gain of the equalizer circuitry, and the second output signal may be used in control of the AC gain of the equalizer circuitry.04-08-2010
20100080278FILTER STRUCTURE IMPLEMENTATION RELATING TO A LINEAR SYSTEM SOLUTION - A method used in a time domain equalizer is provided. A method comprising the steps of: providing a time domain equalizer comprising a feed forward equalizer and a feedback equalizer; and using a filter circuit or structured implementation to incorporate conjugate gradient iteration in order to calculate a set of coefficients of the time domain equalizer. Whereby matrix times vector operations is converted into filtering using the filter circuit.04-01-2010
20100080276METHOD FOR NON-PILOT TONE DATA-AIDED CARRIER FREQUENCY TRACKING - A method comprising the steps of providing a slicer for slicing real values of an equalizer output; and cross correlating an equalizer input with an output of the slicer is provided.04-01-2010
20090207900Apparatus for Stabilizing Convergence of an Adaptive Line Equalizer - Illustrative embodiments provide a computer implemented method and an apparatus for data decorrelation in a line equalizer adaptive system. The apparatus comprises an input and an output, forming a data path there between, wherein the input capable of receiving data to create received data and the output capable of sending data. The apparatus further comprises an adaptive equalizer capable of equalizing the received data, connected to the data path, and a synchronous decorrelator connected to the data path, in communication with the adaptive equalizer, wherein the synchronous decorrelator evaluates an adapt enable output for each received data input to the adaptive equalizer to determine whether the adaptive equalizer can update settings of the line equalizer adaptive system.08-20-2009
20110200090METHOD FOR AN EQUALIZER COMPUTATION IN A MEDIA SYSTEM USING A DATA SET SEPARATOR SEQUENCE - An equalizer coefficients generator receives a DSS sequence and a DSS readback sequence, which is a function of a channel processing of the DSS sequence by a read channel. The generator generates a coefficient cyclic equalizer vector as a function of the DSS sequence and the DSS readback sequence. The generator further generates an error signal as a function of a comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector. An unacceptable error signal indicates a need to adjust the coefficient cyclic equalizer vector to yield an acceptable comparison of the DSS sequence and an equalization of the DSS readback sequence based on the coefficient cyclic equalizer vector.08-18-2011
20090190649Conditioning Circuit that Spectrally Shapes a Serviced Bit Stream - A high-speed bit stream interface module interfaces a high-speed communication media to a communication Application Specific Integrated Circuit (ASIC) via a Printed Circuit Board (PCB). The high-speed bit stream interface module includes a line side interface, a board side interface, and a signal conditioning circuit. The line side interface includes a media coupler that receives the line side media, such as copper media or optical media. The board side interface couples the high-speed serial bit stream interface module to the PCB. A signal conditioning circuit communicatively couples to the line side interface and to the board side interface. The signal conditioning circuit receives an RX signal from the line side interface, conditions the RX signal, and provides the RX signal to the board side interface. The signal conditioning circuit receives a TX signal from the board side interface, conditions the TX signal, and provides the TX signal to the board side interface.07-30-2009
20090190648DIFFERENTIAL TRANSMITTER - A TMDS driver outputs differential signals via a pair of differential signal lines. The input differential pair includes a first transistor and a second transistor with one terminals thereof connected to each other so as to form a common terminal, and operates with termination resistors, which are arranged on the side of a differential receiver connected via the differential signal lines, as a part of the load. A tail current source supplies constant current to the input differential pair. An impedance adjusting unit is provided between the input differential pair and the differential signal lines, and adjusts the load impedance of the first transistor and the second transistor.07-30-2009
20120106618METHOD FOR RECEIVING FREQUENCY DOMAIN MULTIPLEXED SIGNAL AND DEVICE FOR RECEIVING FREQUENCY DOMAIN MULTIPLEXED SIGNAL - A frequency domain multiplexed signal receiving method which decodes received signals that are multiplexed in a frequency domain, includes: a digital signal acquisition step of acquiring digital signals from the received signals that are multiplexed in the frequency domain; an offset discrete Fourier transform step of applying an offset discrete Fourier transform to odd discrete point numbers based on the acquired digital signals; and a decode step of decoding frequency domain digital signals in the frequency domain obtained by the offset discrete Fourier transform, and that are the frequency domain digital signals of one or more frequency channels.05-03-2012
20120106617SYSTEM AND METHOD FOR ANTICIPATORY RECEIVER SWITCHING BASED ON SIGNAL QUALITY ESTIMATION - In various embodiments, a first and second complex multiplier may be configured to receive an input signal and provide a baseband I component signal and a baseband Q component signal, respectively. A first and second filter may be configured to filter the baseband I component signal and the baseband Q component signal, respectively. An equalizer may be configured to equalize the filtered baseband I component signal and the filtered baseband Q component signal. A carrier recovery portion may be configured to generate a reference signal based on the equalized filtered baseband I component signal and the equalized filtered baseband Q component signal. A first and second multilevel comparator may be configured to receive the equalized filtered baseband I component signal from the carrier recovery portion and provide an output I and receive the equalized filtered baseband Q component signal and provide an output Q signal for further modulation.05-03-2012
20120106616ADAPTIVE EQUALIZATION IN THE PRESENCE OF BURST ERRORS - Methods for providing adaptive equalization in the presence of a burst error are provided. If an equalization algorithm has converged and burst errors are present during a symbol interval, the equalizer coefficients remain unchanged during the symbol interval. If the burst error is no longer present during the next symbol interval, the equalizer coefficients are updated based on the previously converged coefficients.05-03-2012
20110170587EDGE EQUALIZER - To compensate for roll-off while estimating a communication channel, an estimate of the channel is provided using a signal transmitted via the communication channel. The pilot tones positioned along the edges of the estimated channel are divided by the corresponding pilot tones of the received signal to generate a first number of ratios. An algorithm is thereafter applied to the first number of ratios to generate a second number of ratios associated with the non-pilot tones positioned along the edges of the estimated channel. Next, numbers that are inverse of the first and second number of ratios are applied to the pilot and non-pilot tones positioned along the edges of the estimated channel to compensate for the roll-offs in the estimated channel.07-14-2011
20110170589APPARATUS FOR ESTIMATING AND CORRECTING BASEBAND FREQUENCY ERROR IN A RECEIVER - An apparatus for estimating and correcting baseband frequency error in a receiver is disclosed. An equalizer performs equalization on a sample data stream and generates filter tap values based on the equalization. An estimated frequency error signal is generated based on at least one of the filter tap values. A rotating phasor is generated based on the estimated frequency error signal. The rotating phasor signal is multiplied with the sample data stream to correct the frequency of the sample data stream. Alternatively, a channel estimator performs channel estimation and generates Rake receive finger weights based on at least one of the finger weights. An estimated frequency error signal is generated based on at least one of the finger weights.07-14-2011
20110170588APPARATUS AND METHOD FOR CHIP LEVEL EQUALIZATION IN WIRELESS COMMUNICATION SYSTEM - An apparatus and a method for improving performance of an equalizer in a wireless communication system are provided. The apparatus of a reception end includes a search unit and an estimator. The search unit determines power values of respective taps inside a window based on a signal received via a pilot channel, and classifies the taps into one or more meaningful taps and one or more noise taps. The estimator allocates one or more 1-tap channel estimators to the one or more meaningful taps, and determines a channel estimation vector based on a channel estimation value of the one or more meaningful taps determined by the one or more 1-tap channel estimators.07-14-2011
20110268173METHOD FOR ADAPTING FILTER CUT-OFF FREQUENCIES FOR THE TRANSMISSION OF DISCRETE MULTITONE SYMBOLS - The invention creates a method for adapting filter cut-off frequencies for the transmission of discrete multitone symbols, where a transmit symbol datastream consisting of discrete multitone symbols is applied to an interpolation device, the transmit symbol datastream is interpolated with a symbol rate in the interpolation device, an interpolated symbol datastream is filtered in a first low-pass filtering device in accordance with a first filter cut-off frequency, which can be predetermined by a first filter cut-off frequency determining device, a digital symbol datastream obtained after a digital-analog conversion, transmission and analog-digital conversion, is filtered at the receiver end in a second low-pass filtering device in accordance with a second filter cut-off frequency, which can be predetermined by a second filter cut-off frequency determining device, in order to provide an equalized symbol datastream, the equalized symbol datastream is decimated in a decimation device and the decimated received symbol datastream consisting of discrete multitone symbols is provided to a multitone receiver device.11-03-2011
20090262797SYSTEM AND METHOD OF EQUALIZATION OF HIGH SPEED SIGNALS - In one aspect, the present invention is directed to a technique of, and system for enhancing the performance of high-speed digital communications through a communications channel, for example a backplane. In this aspect of the present invention, a transmitter includes equalization circuitry to compensate for bandwidth limitations and reflections in high-speed digital communication systems. In one embodiment, the equalization circuitry is designed, programmed and/or configured to introduce intersymbol interference in order to improve the signal integrity in high-speed communications and enhance the operation and performance of such systems. In this regard, the equalization circuitry includes temporally overlapping leading and/or trailing taps (relative to the data (symbol) signal) to reduce, minimize, mitigate or effectively eliminate pre-cursor and/or post-cursor intersymbol interference due to, for example, bandwidth limitations and reflections in high-speed digital communication systems. The amount of equalization may be programmed, adjusted or controlled by varying the positioning of the tap(s), varying the coefficients of the tap(s), and/or varying the pulse durations of the tap(s) (that is, the pulse duration of the equalization signal attributed to the tap).10-22-2009
20090262796 EQUALIZING FILTER CIRCUIT - An equalizing filter circuit includes a first transmission line in which a plurality of first delay devices 10-22-2009
20090279597DIGITAL EQUALIZER FOR HIGH-SPEED SERIAL COMMUNICATIONS - Incoming data at a high-speed serial receiver is digitized and then digital signal processing (DSP) techniques may be used to perform digital equalization. Such digital techniques may be used to correct various data anomalies. In particular, in a multi-channel system, where crosstalk may be of concern, knowledge of the characteristics of the other channels, or even the data on those channels, may allow crosstalk to be subtracted out. Knowledge of data channel geometries, particularly in the context of backplane transmissions, may allow echoes and reflections caused by connectors to be subtracted out. As data rates increase, fractional rate processing can be employed. For example, the analog-to-digital conversion can be performed at half-rate and then two DSPs can be used in parallel to maintain throughput at the higher initial clock rate. At even higher rates, quadrature techniques can allow analog-to-digital conversion at quarter-rate, with four DSPs used in parallel.11-12-2009
20090285276Apparatus, method, and computer program product for demodulation - The invention relates to an apparatus comprising: an estimator configured to estimate a channel response; a determiner configured to determine an equalizer coefficient vector; a calculator configured to calculate a symbol amplitude by using the equalizer coefficient vector and the estimated channel response; a determiner configured to determine a weighting factor by using the symbol amplitude; an estimator configured to estimate soft bits; and a weighter configured to weight the estimated soft bits by using the weighting factor for scaling the estimated soft bits to a predetermined dynamic range in a manner enabling their presentation using a predetermined limited numerical accuracy.11-19-2009
20090296800DTMB-based control system and receiving system having the same - A DTMB-based control system includes a carrier mode detector, a TPS decoder, a first latch, a second latch, and a latch controller. The carrier mode detector receives a number of N12-03-2009
20100111158EQUALIZER AND METHOD APPLIED THERETO - The equalizer presented includes a first feed-forward equalization module, a second feed-forward equalization module, and a phase error corrector. The first and the second feed-forward equalization modules respectively receives an input real-part component signal and an input imaginary-part component signal of a complex input signal and respectively equalizes the input real-part component signal and the input imaginary-part component signal to generate a first real-part component signal and a first imaginary-part component signal. The phase error corrector is coupled to the first and the second feed-forward equalization modules for adjusting a complex phase corresponding to the first real-part component signal and the first imaginary-part component signal to generate a second real-part component signal and a second imaginary-part component signal according to a phase error information.05-06-2010
20080298452FAST SQUARE ROOT ALGORITHM FOR MIMO EQUALIZATION - Systems and methodologies are described that facilitate equalization of received signals in a wireless communication environment. Using multiple transmit and/or receive antennas and MIMO technology, multiple data streams can be transmitted within a single tone. During equalization, receivers can separate data received within a tone into individual data streams. The equalization process generally is computationally expensive. Equalizer functions include the inverse operation, which can be computed using the fast square root method; however, the fast square root method involves large numbers of computations for a set of matrices, where the size of a matrix in the set of matrices increases with the number of transmit or receive antennas. Utilizing a modification of the fast square root method, a subset of the elements of the matrices can be selected and updated to reduce the number and/or complexity of computations.12-04-2008
20090296801METHOD AND SYSTEM FOR SELECTIVE EQUALIZATION ENABLEMENT BASED ON MODULATION TYPE - Aspects of a method and system for selective equalization enablement based on modulation type may be found in a method for processing a radio frequency (RF) signal that comprises receiving a Bluetooth signal via an RF channel, detecting a modulation type of the received Bluetooth signal, and selecting an equalization circuit for processing the received Bluetooth signal based on the detected modulation type. The method may also comprise determining a data rate based on the detected modulation type.12-03-2009
20080247452ADAPTIVE EQUALIZER FOR USE WITH CLOCK AND DATA RECOVERY CIRCUIT OF SERIAL COMMUNICATION LINK - An adaptive equalizer system for use in a serial communication link uses timing information generated by a phase detector of a clock and data recovery circuit of the serial communication link and a frequency pattern of the recovered data to determine whether the data received over the serial communication link is over-equalized or under-equalized. The equalizer strength of the adaptive equalizer system is adjusted based on such determination.10-09-2008
20100142610PARTIAL RESPONSE RECEIVER - A signaling system is described. The signaling system comprises a transmit device, a receive device including a partial response receive circuit, and a signaling path coupling the transmit device and the receive device. The receive device observes an equalized signal from the signaling path, and includes circuitry to use feedback from the most recent previously resolved symbol to sample a currently incoming symbol. The transmit device equalizes transmit data to transmit the equalized signal, by applying weighting based on one or more data values not associated with the most recent previously resolved symbol value.06-10-2010
20080232451METHOD AND APPARATUS FOR EQUALIZATION OF FAST CHANGING CHANNELS IN A TDS-OFDM SYSTEM - A method for channel equalization is provided. The method comprises the steps of: subdividing a received symbol portion into segments wherein each segment is associated with a known, segmented channel characteristic among a set of segmented, known channel characteristics spanning the received symbol.09-25-2008
20090168863POLAR TRANSMITTER WITH DIGITAL AND ANALOG FILTERING OF ENVELOPE - A calibration circuit measures the variation in a filter resistor within the analog domain of the envelope path of a polar transmitter and produces a digital value representative of that variation. A digital processor determines a digital control signal from the digital value that is used to compensate, in the digital domain of the envelope path, for the variation in the filter resistor in the analog domain.07-02-2009
20080279271Very High Speed Low Power Receiver Equalization System For Non-Return-To-Zero Transmission - A very high speed low power receiver equalization system for non-return-to-zero transmission is disclosed. The equalizer comprises a three stage architecture, preferably controlled by three main parameters, the low frequency gain controlled through Rfb, the peaking frequency settled by the capacitor Cfpk, and the variable peak boosting Gpk which provides the equalizer transfer function and the optimum controls of the signal gain characteristic in order to compensate the ISI at the receiver input and consequently allow High speed, reliable links.11-13-2008
20120294351Equalizer and Communication System - An equalizer for compensating an input signal in a receiver of a communication system is disclosed. The equalizer includes a first transistor, having a gate for receiving a positive input voltage of the input signal; a second transistor, having a gate for receiving a negative input voltage of the input signal, and a source coupled to a source of the first transistor; and a resistor, connected with at least one capacitor to be coupled between a drain of the first transistor and a drain of the second transistor, for optimizing a resistance of the resistor, to compensate the input signal.11-22-2012
20080291992SYSTEM AND METHOD OF DETECTING BURST NOISE AND MINIMIZING THE EFFECT OF BURST NOISE - A communication system and a method which can reduce the effect of burst noise. The communication system comprises a controllable oscillator, a mixer, a decision circuit, a comparator, a loop filter, and a controller. The controllable oscillator generates an oscillating signal. The mixer coupled to the controllable receives input data and mixes the input data with the oscillating signal. The decision circuit receives the mixed input data and generates an estimated symbol. The comparator generates a decision error between the estimated symbol and the mixed input data. The loop filter coupled to the controllable oscillator filters the decision error, and generates a filtered decision error, and the controllable oscillator generates the oscillating signal according to the filtered decision error. The controller reduces a bandwidth of the loop filter according to the decision error.11-27-2008
20080291991RADIO RECEIVER HAVING A CHANNEL EQUALIZER AND METHOD THEREFOR - A radio receiver for receiving a signal is provided. The radio receiver comprises an equalizer configured to perform a constant modulus algorithm initialized using a first set of coefficients on the received signal and for generating an equalized signal. The radio receiver further comprises a demodulator coupled to the equalizer for demodulating the equalized signal. The radio receiver further comprises a lowpass filter coupled to the demodulator for lowpass filtering the demodulated signal to detect a spurious signal and to generate an offset signal. The radio receiver further comprises a coefficient generator coupled to the lowpass filter and configured to compare the offset signal to a predetermined threshold, and if the offset signal satisfies a predetermined condition in relation to the predetermined threshold, then to generate a second set of coefficients for re-initializing the constant modulus algorithm.11-27-2008
20080310494Leakage Scheme for Receiver - A receiver for processing a transmission signal distorted by a transmission channel is described. The receiver has an adaptive signal processor (12-18-2008
20080310492Parameter Adjustment Device and Parameter Adjustment Method - Transmission equipment that can be used up to a high frequency and simplifies a circuit design includes a THP preceding means on a transmitting side, and an equalizer means, wherein analog processing is carried out on a receiving side. Compensation of the frequency characteristic of a transmission channel is divided into the THP preceding means on the transmitting side and the equalizer means, so that due to compensation by the equalizer circuit, the absolute value of a THP coefficient becomes small, and a DAC with lower resolution, wherein stability of a loop of the THP increases, can be used. Detailed adjustment for adapting to the characteristic of a transmission channel is carried out by the THP, so that the equalizer circuit is only required to roughly compensate, and is not required to adjust. As a result, the equalizer circuit can be of a simple design.12-18-2008
20090034600Method for manufacturing an equalizer - A method for manufacturing an equalizer. The method first acquires a transmission line scattering-parameter, and a gain of the transmission line scattering-parameter at a frequency02-05-2009
20080240220DIGITAL FILTER AND METHOD FOR FILTERING - Digital filter, comprising a multiplier configured to generate an intermediate signal, wherein said intermediate signal is generated by multiplying an input signal with a filter coefficient signal, wherein said multiplier is operated at a clock rate and said input signal has a sampling rate, wherein said clock rate is higher than said sampling rate; a first buffer configured to supply said filter coefficient signal to said multiplier at said clock rate, wherein said filter coefficient signal represents N filter coefficients in a periodic order, wherein N denotes the order of said digital filter; a second buffer configured to buffer N/2 samples of an intermediate output signal and to generate a respective time delayed intermediate output signal; and an adder configured to generate said intermediate output signal or an output signal of said digital filter based on an addition of said time delayed intermediate output signal and said intermediate signal.10-02-2008
20080253439DE-EMPHASIZING CABLE EQUALIZER - In accordance with the teachings described herein, an extended equalizer circuit is provided for equalizing a digital communication signal transmitted over a transmission medium that causes a frequency-dependent attenuation of the digital communication signal. An equalizer may be used that includes a linear equalization circuit and a non-linear equalization circuit, the linear equalization circuit being configured to apply a linear filter to the digital communication signal to compensate for the frequency-dependent attenuation caused by a first portion of the transmission medium, and the non-linear equalization circuit being configured to apply one or more non-linear operations to the digital communication signal. A de-emphasizing equalizer circuit may be coupled in series between the transmission medium and the equalizer and configured to apply an additional linear filter to the digital communication signal in order to compensate for the frequency-dependent attenuation caused by a second portion of the transmission medium10-16-2008
20100135377FREQUENCY DOMAIN EQUALIZER FOR DUAL ANTENNA RADIO - A Radio Frequency (RF) receiver includes a RF front end and a baseband processing module coupled to the RF front end that is operable to receive a time domain signal that includes time domain training symbols and time domain data symbols. The baseband processing module includes a channel estimator operable to process the time domain training symbols to produce a time domain channel estimate, a Fast Fourier Transformer operable to convert the time domain channel estimate to the frequency domain to produce a frequency domain channel estimate, a weight calculator operable to produce frequency domain equalizer coefficients based upon the frequency domain channel estimate, an Inverse Fast Fourier Transformer operable to converting the frequency domain equalizer coefficients to the time domain to produce time domain equalizer coefficients, and an equalizer operable to equalize the time domain data symbols using the time domain equalizer coefficients.06-03-2010
20080310493Fast training equalization of a signal by using adaptive-iterative algorithm with main path phase correction - A signal receiver inputs a signal, computes a set of equalizer tap values during a signal acquisition phase by applying an algorithm iteratively to a given set of training data contained within the signal, and uses the set of equalizer tap values to perform signal equalization during the signal acquisition phase. The algorithm includes computing and applying phase correction to the pre-equalized signal at each adaptation step to correct for phase error related to the main path only, of the input signal.12-18-2008
20080198915SYSTEM AND METHOD OF EQUALIZATION OF HIGH SPEED SIGNALS - In one aspect, the present invention is directed to a technique of, and system for enhancing the performance of high-speed digital communications through a communications channel, for example a backplane. In this aspect of the present invention, a transmitter includes equalization circuitry to compensate for bandwidth limitations and reflections in high-speed digital communication systems. In one embodiment, the equalization circuitry is designed, programmed and/or configured to introduce intersymbol interference in order to improve the signal integrity in high-speed communications and enhance the operation and performance of such systems. In this regard, the equalization circuitry includes temporally overlapping leading and/or trailing taps (relative to the data (symbol) signal) to reduce, minimize, mitigate or effectively eliminate pre-cursor and/or post-cursor intersymbol interference due to, for example, bandwidth limitations and reflections in high-speed digital communication systems. The amount of equalization may be programmed, adjusted or controlled by varying the positioning of the tap(s), varying the coefficients of the tap(s), and/or varying the pulse durations of the tap(s) (that is, the pulse duration of the equalization signal attributed to the tap).08-21-2008
20100142609Reception Station, Communication System And Transmission Diversity Control Method - In a transmission diversity control method in which a request to start or stop transmission diversity is issued by a reception station to a transmission station having a transmission diversity function, the reception station is provided with an equalizer to reduce multipath interference on the basis of a signal correlation, a transmission diversity start request is issued from the reception station to the transmission station when an effect generated by the equalizer is small, and a transmission diversity stop request is issued from the reception station to the transmission station when the effect generated by the equalizer is large.06-10-2010
20090074050METHOD AND APPARATUS FOR RECEIVING CODED SIGNALS WITH THE AID OF CHANNEL STATE INFORMATION - Method and apparatus for receiving coded signals with the aid of CSI are provided. The method comprises: performing channel estimation to obtain a CFR estimation vector; computing a squared magnitude of the CFR estimation vector, and obtaining a normalization factor α by averaging the squared magnitudes of CFR estimations on all N subcarriers; finding a norm-shift operand m satisfying the condition that α03-19-2009
20090185612Method and apparatus for single burst equalization of single carrier signals in broadband wireless access systems - A receiver implementing a single carrier single burst equalization (SC-SBE) method is capable of achieving near optimal reception of individual single carrier RF bursts by making an accurate estimate of the burst's propagation channel impulse response (CIR). The SC-SBE method uses a CIR based coefficient computation process to obtain filter coefficients for a minimum mean square error decision feedback equalizer (MMSE-DFE). The MMSE-DFE filter computation process computes a sufficiently large number of coefficients for the DFE filters, i.e., the feed forward filter (FFF) and feedback filter (FBF), so that each filter spans the maximum anticipated length of the CIR. In order to implement the filters efficiently, a coefficient selection process eliminates less significant computed FFF and FBF coefficients. The resulting FFF and FBF are sparse filters in that most of the taps in the filter delay lines do not have a filter coefficient. Such filters may be efficiently implemented in the time domain.07-23-2009
20090129457EQUALIZER CIRCUIT - In an equalizer circuit of one aspect, a first Fourier transform circuit Fourier-transforms an input signal and outputs a corresponding first Fourier-transformed signal, and a first extracting circuit extracts a plurality of pilot symbols from the first Fourier-transformed signal. An inverse Fourier transform circuit calculates a complex gain of each path of the input signal by inverse-transforming the plurality of pilot symbols extracted by the first extracting circuit. A detecting circuit detects at least one of a power value and a mean amplitude of the input signal, and a coefficient determining circuit determines a coefficient corresponding to the at least one of the power value and the mean amplitude detected by the detecting circuit. A second extracting circuit extracts complex gains having a power larger than a threshold obtained by multiplying the coefficient determined by the coefficient determining circuit by a value obtained by integrating the power for a period of time, wherein the power is obtained from the complex gains of each path of the input signal calculated by the inverse Fourier transform circuit. A second Fourier transform circuit Fourier-transforms the extracted complex gains from the second extracting circuit to obtain a corresponding second Fourier-transformed signal, and an equalizing calculation circuit equalizes the input signal using the second Fourier-transformed signal.05-21-2009
20090129458METHOD AND APPARATUS FOR ESTIMATING THE STEP-SIZE OF AN ADAPTIVE EQUALIZER - A step-size estimator for controlling the step-size of an adaptive equalizer incorporated in a transceiver (e.g., a wireless transmit/receive unit (WTRU)). The step-size estimator updates at least one adaptive equalizer tap used by the adaptive equalizer based on an apparent speed of a channel established between the transceiver and another transceiver. The step-size estimator includes a speed estimator, a signal-to-noise ratio (SNR) averager and a step-size mapping unit. The speed estimator is used to estimate the apparent speed of the channel (i.e., the observed and/or measured rate of change of the channel impulse response). The SNR averager generates a common pilot channel (CPICH) SNR estimate. The step-size mapping unit uses the speed estimate and the CPICH SNR estimate to generate a step-size parameter, μ, and a filter taps leakage factor parameter, α, used by the adaptive equalizer to update the filter tap coefficient.05-21-2009
20090252214RECEIVER - A receiver in which computation is simplified can be obtained by using a common factor for filter coefficients of FIR filters corresponding to a plurality of transmitting antennas and by using only the middle column of an inverse matrix of a gain matrix when the common factor is computed.10-08-2009
20110222593CHANNEL EQUALIZER AND METHOD OF PROCESSING BROADCAST SIGNAL IN RECEIVING SYSTEM - A channel equalizer includes an overlap unit, an estimator, a calculator, a compensator, and a save unit. The overlap unit overlaps a group of data packets in a broadcast signal. The group data packets include a head, a body, and a tail, and a known data sequence is periodically included in the body. The estimator estimates a CIR of each data region the body using the known data sequence, and it further estimates CIRs of data regions in the head or tail using the CIRs obtained for the data regions in the body. The calculator calculates equalization coefficients based on the CIRs estimated by the estimator, and the compensator compensates channel distortion of the overlapped data using the equalization coefficients. The save unit saves the compensated data.09-15-2011
20090080507DIGITAL BROADCASTING SYSTEM AND METHOD OF PROCESSING DATA IN DIGITAL BROADCASTING SYSTEM - A digital broadcasting system and a data processing method are disclosed. A receiver receives a broadcast signal including mobile service data and main service data. A known data detector detects known data from the broadcast signal. An equalizer performs channel equalization on the mobile service data received by means of the detected known data. A RS frame decoder acquires a RS frame from the channel-equalized mobile service data. A management processor checks a TP header contained in the RS frame, and identifies which data is contained in the RS frame. MH presentation processor displays the data contained in the RS frame.03-26-2009
20090052516Per-survivor based adaptive equalizer - A method used in an adaptive survivor based channel equalizer, the method comprises selecting at a decision time a survivor in a Viterbi trellis and a corresponding equalizer, adaptively updating at the decision time the corresponding equalizer to define a new corresponding equalizer for use at a next decision time, retrieving the new corresponding equalizer as defined at an earlier decision time, and using the new corresponding equalizer as defined at an earlier decision time as an equalizer for other survivors in the Viterbi trellis at the next decision time. A corresponding adaptive survivor based channel equalizer includes a fixed pre-filter configured to provide a pre-filtered signal to a reduced state sequence estimator (RSSE) which is configured for providing recovered symbols. A coefficient adaptor is coupled to the RSSE and configured to essentially perform the method.02-26-2009
20090097538Methods And Apparatus For Adaptive Equalization Using Pattern Detection Methods - Methods and apparatus are provided for adaptive equalization using pattern detection methods. A signal is equalized by detecting one or more predefined patterns in the signal; and then changing one or more parameters of the equalization, such as an equalization adaptation rate, based on the detected predefined patterns. The equalization adaptation rate can be increased upon the detection of one or more predefined patterns and then gradually reduced to a steady state value. Equalization parameters that have been previously obtained for various patterns can optionally be loaded upon detection of a corresponding pattern The equalization can optionally be suppressed for one or more predefined patterns. The patterns can be detected, for example, by searching for the one or more predefined patterns in the signal, or by performing a statistical correlation of the signal to detect the one or more predefined patterns.04-16-2009
20090097539COMMUNICATIONS SYSTEM USING ADAPTIVE FILTER AND VARIABLE DELAY BEFORE ADAPTIVE FILTER TAPS - A communication system receives a modulated signal that carries encoded communication data. An adaptive filter has a plurality of adaptive filter taps and weighted coefficients and a variable delay circuit operative before the adaptive filter taps for separating the spacing of multipath introduced by adaptive filter and producing a filtered output signal with improved multipath performance. A demodulator and decoder receive the filtered output signal from the adaptive filter and demodulate and decode the signal to obtain the communications data.04-16-2009
20120069892TRANSMITTING/RECEIVING SYSTEM AND BROADCAST SIGNAL PROCESSING METHOD - A receiving system and a method for receiving and processing a broadcast signal including mobile service data are disclosed. The receiving system includes a tuner, a demodulator, a block decoder and an RS frame decoder. The tuner receives a broadcast signal including first mobile service data and second mobile service data. The demodulator demodulates the broadcast signal. The block decoder performs turbo-decoding on the first and second mobile service data included in the demodulated broadcast signal. The RS frame decoder builds a primary RS frame by collecting the turbo-decoded first mobile service data and performs error correction decoding on the primary RS frame. The RS frame decoder also builds a secondary RS frame by collecting the second mobile service data and performs error correction decoding on the secondary RS frame.03-22-2012
20090092182METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING SPACE BLOCK CODING SIGNAL THROUGH ITERATIVE MULTI-USER DETECTION - A method and apparatus for transmitting and receiving a space block coding signal through Iterative Multi-user Detection is provided. The apparatus includes a multi-user interference cancellation unit which cancels multi-user interference in a received signal and outputs a first signal and a second signal that are sequentially transmitted from two transmitting antennas, a linear combiner which performs linear combination for the first signal and the second signal, and an equalizer which applies different equalization coefficients to the combined first signal and the second signal, respectively, to perform frequency-domain equalization.04-09-2009
20090080508FAST SQUARE ROOT ALGORITHM FOR MIMO EQUALIZATION - Systems and methodologies are described that facilitate equalization of received signals in a wireless communication environment. Using multiple transmit and/or receive antennas and MIMO technology, multiple data streams can be transmitted within a single tone. During equalization, receivers can separate data received within a tone into individual data streams. The equalization process generally is computationally expensive. Equalizer functions include the inverse operation, which can be computed using the fast square root method; however, the fast square root method involves large numbers of computations for a set of matrices, where the size of a matrix in the set of matrices increases with the number of transmit or receive antennas. Utilizing a modification of the fast square root method, a subset of the elements of the matrices can be selected and updated to reduce the number and/or complexity of computations.03-26-2009
20110228839DIGITAL ADAPTIVE CHANNEL EQUALIZER - A channel equalizer that compensates for signal distortion of a signal in a communication channel includes an equalization filter, which gain-equalizes a received signal received through the communication channel, and an equalization control circuit, which generates a gain control signal for controlling the gain of the equalization filter. The equalization control circuit specifies a phase switch in data obtained by the equalization filter as an isolated bit and generates the gain control signal based on a width of the isolated bit.09-22-2011
20110228838APPARATUS FOR IMPULSE NOISE MITIGATION - An apparatus for noise mitigation in a multi-carrier communication system includes a filter to receive a signal from an analog front end, a time-domain equalizer (TEQ) coupled with the filter, a fast Fourier transform (FFT) module, a frequency-domain equalizer (FEQ) coupled with the FFT module, a slicer to serve as a decision device, and a controller to calculate a power of signal at at least one of an input of the filter, an input of the TEQ, an output of the TEQ, an output of the FFT module, an output of the FEQ or an output of the slicer and compare at least one of the power of the at least one signal with a respective threshold so as to determine whether impulse noise occurs, wherein the controller is configured to disable adaptation of system parameters in at least one of the FEQ, a phase-lock loop (PLL) or a digital echo canceller (DEC) when impulse noise is detected.09-22-2011
20100002760System and Method for Linear Distortion Estimation by Way of Equalizer Coefficients - Provided is a method and system for estimating distortion in a communications channel including an adaptive equalizer. The method includes determining one or more adaptive filter coefficients associated with a signal passed through the equalizer. The method also includes estimating un-equalized channel distortion based upon the determined adaptive filter coefficients.01-07-2010
20090097540RECEIVING APPARATUS HAVING EQUALIZER, AND RECEIVING METHOD - A timing recovery circuit recovers the symbol timing of a modulation signal. A carrier recovery circuit corrects the frequency shifts of output signals of the timing recovery circuit. An FIR equalizer having a plurality of taps, and corrects the distortions of output signals of the carrier recovery circuit. A control circuit dynamically controls the number of taps used in the FIR equalizer.04-16-2009
20090003427BURSTY INTERFERENCE SUPPRESSION FOR COMMUNICATIONS RECEIVERS - Techniques are provided for suppressing interference by taking into account the possible bursty nature of co-channel interference in a communication system. In an aspect, interference levels are separately computed for first and second data portions of a desired signal. The computed interference levels may be used to scale the corresponding data portions for subsequent processing.01-01-2009
20080317112BIDIRECTIONAL EQUALIZER WITH IMPROVED EQUALIZATION EFFICIENCY USNG VITERBI DECODER INFORMATION AND EQUALIZATION METHOD USING THE BIDIRECTIONAL EQUALIZER - A bidirectional equalizer and an equalization method using the bidirectional equalizer. The bidirectional equalizer includes: a first equalizer to eliminate inter-symbol interference present in a data sequence transmitted from a transmitter and to generate a first candidate data sequence; a first time reverse operator to reverse the order of the transmitted data sequence and to generate a reversed data sequence; a second equalizer to eliminate inter-symbol interference present in the reversed data sequence and to generate a second candidate data sequence; a forward Viterbi decoder to receive the first candidate data sequence, and to decode and output the first candidate data sequence for every data symbol using a first minimum path metric calculated by a maximum likelihood (ML); a reverse Viterbi decoder to receive the second candidate data sequence, and to decode and output the second candidate data sequence for every data symbol using a second minimum path metric calculated by ML; a second time reverse operator to reverse the order of the decoded second candidate data sequence output from the reverse Viterbi decoder and to output the reversed decoded second candidate sequence; and an arbitrator to compare the first minimum path metric with the second minimum path metric, and to selectively output an output of the forward Viterbi decoder or an output of the second time reverse operator according to the comparison result.12-25-2008
20090219984Autoregressive Moving Average Modeling for Feedforward and Feedback Tomlinson-Harashima Precoder Filters - Apparatus and methods provide a Tomlinson-Harashima precoder scheme in which a feedback filter may be constructed to match an approximated feedforward filter, where the feedforward filter is approximated using autoregressive moving average modeling.09-03-2009
20090245341CHANNEL EQUALIZER - A channel equalizer arranged to receive a data signal encoded by a plurality of amplitude levels, the circuitry including a filter having a plurality of taps, each tap generating an output signal based on a coefficient, an input for receiving an error signal for adapting the coefficients, and an output for outputting a filtered signal; and blind error generation circuitry arranged to generate the error signal, the blind error generation circuitry including: error estimating circuitry arranged to estimate the error of the filtered signal based on maximum likelihood; and adding circuitry coupled to the error estimating circuitry and to the output of the filter and arranged to add at least part of the filtered signal to the error estimated by the error estimating circuitry to generate the error signal.10-01-2009
20080260015METHOD AND APPARATUS FOR IMPROVED HIGH-SPEED ADAPTIVE EQUALIZATION - A method and apparatus for improved high-speed adaptive equalization that may operate effectively even in systems experiencing severe interference by using one or more error generators and taking multiple samples across a bit interval. Advantageously, a preferred embodiment of the current invention may be deployed in a clockless configuration. Preferably, one or more controllable analog filters may be controlled by one or more microprocessors used to assess the error data from the error generators and to calculate the appropriate coefficients for the filters according to one or more error minimization algorithms. Preferably, the steps of sampling, assessment, calculation and coefficient setting may be done iteratively to converge to an optimum set of filter values and/or respond dynamically to signals with time-varying noise and interference characteristics.10-23-2008
20100150220METHOD AND DEVICE FOR RECEIVING A DATA SIGNAL CONSISTING OF SYMBOL BLOCKS AND CORRESPONDING COMPUTER PROGRAM - A method is provided for receiving a received data signal including at least one symbol block received and representative of a source signal. The method includes at least one iteration for improving an estimate of the received signal and including the following steps, for a current equalized symbol block: obtaining one or more decided bits, by bit-by-bit decoding a current subset of bits; updating one or more symbols, according to the decoded bit or bits, delivering an updated block of estimated symbols; determining a block of equalized symbols enhanced by canceling interferences, taking account of the updated block of estimated symbols.06-17-2010
20100034252Digital Transmitter - An equalizer provided in a digital transmitter compensates for attenuation in a signal channel to a digital receiver. The equalizer generates signal levels as a logical function of bit history to emphasize transition signal levels relative to repeated signal levels. The preferred equalizer includes an FIR transition filter using a look-up table. Parallel circuits including FIR filters and digital-to-analog converters provide a high speed equalizer with lower speed circuitry. The equalizer is particularly suited to in-cabinet and local area network transmissions where feedback circuitry facilitates adaptive training of the equalizer.02-11-2010
20090122853CHANNEL TRACKING METHODS FOR SUBSPACE EQUALIZERS - A receiver includes a subspace filter having first and second basis filters, with the first basis filter module generating a weighted average channel estimate. The receiver collects a plurality of channel estimates over an interval and combines the plurality of channel estimates using a weighting factor and summing to generate the weighted average channel estimate. The receiver generates a weighting factor for each of the plurality of channel estimates over the interval the weighting factors vary as a function of the relative velocity of the receiver so that the estimates closest in time to the current estimate are weighted more heavily than estimates further spaced in time from the current estimate.05-14-2009
20090316768METHOD AND APPARATUS FOR GENERATING EQUALIZER FILTER TAP COEFFICIENTS - A method and apparatus generating an error signal and an update vector signal used to generate filter tap coefficients for an equalizer filter residing in an equalizer. The equalizer filter outputs an equalized signal in response to receiving a sample data stream. The error signal is generated by down-sampling the equalized signal, subtracting the equalized signal from a reference signal, and filtering and down-sampling the resulting signal. Simultaneously, the update vector signal is generated by converting scalar samples of the sample data stream to a data vector signal and descrambling, filtering, and down-sampling the data vector signal. A tap coefficients generator is used to generate the filter tap coefficients for updating the equalizer filter based on the error signal and the update vector signal.12-24-2009
20090086806TIME VARYING EQUALIZATION - In some implementations, a signal is received at a device and a gain change is detected in a component of the device that affects the signal. A state of an equalizer is adjusted in response to the detected gain change to a first state that reduces transient effects introduced into the signal by one or more components in the device as a result of the gain change. The signal is equalized using the equalizer with the state set to the first state and the state of the equalizer is adjusted from the first state to a second state while equalizing the signal using the equalizer such that the second state passes the signal through the equalizer substantially unchanged.04-02-2009
20100158095RECEIVE APPARATUS AND METHOD IN A MOBILE COMMUNICATION SYSTEM - An apparatus and method for partially updating a tap coefficient and for reducing a hardware size are provided. The apparatus includes a channel estimator, an update period setting unit, and an adaptive algorithm processor. The channel estimator estimates a channel for a received signal. The update period setting unit sets a window corresponding to a filter coefficient update period using channel estimation information of the channel estimator. The adaptive algorithm processor acquires a filter coefficient of the set window interval and performs an equalization algorithm.06-24-2010
20100158094APPARATUS AND METHOD FOR OFDM CHANNEL EQUALIZATION - An apparatus and method for orthogonal frequency division multiplexing (OFDM) channel equalization are disclosed. The apparatus includes a compensation value setting unit setting a compensation value in the form of a diagonal matrix by use of a diagonal matrix of diagonal elements extracted from a channel matrix of an OFDM receiver, and a preset divergence suppression value, an initial estimation value calculation unit calculating an initial estimate value by use of a fast Fourier transform (FFT)-processed signal of the OFDM receiver and the compensation value, an equalization unit detecting a transmission signal to be processed by use of the compensation value, the channel matrix and the diagonal matrix, and a symbol decision unit determining a symbol for an adjacent signal of a transmission signal, which is to be processed among a plurality of signals output from the equalization unit, and providing the symbol-determined adjacent signal to the equalization unit.06-24-2010
20100189171SUBDIMENSIONAL SINGLE-CARRIER MODULATION - A method for modulating a sequence of data symbols such that the transmit signal exhibits spectral redundancy. Null symbols are inserted in the sequence of data symbols such that a specified pattern of K data symbols and N−K null symbols is formed in every period of N symbols in the modulated sequence, N and K being positive integers and K being smaller than N.07-29-2010
20130215952TURBO EQUALIZATION FOR DIVERSITY RECEIVERS - Apparatus includes a slave equalizer chain, which includes a first decoder and a first adaptive filter including first coefficients, and is configured to filter a first signal using the first adaptive filter to produce a first filtered signal, to decode the first filtered signal using the first decoder to generate a first output, and to adapt the first coefficients based at least on the first output. A master equalizer chain includes a second decoder and a second adaptive filter including second coefficients, and is configured to filter a second signal using the second adaptive filter to produce a second filtered signal, to calculate a weighted combination of the second filtered signal and the first filtered signal produced in the slave equalizer chain, to decode the weighted combination using the second decoder to generate a second output, and to adapt the second coefficients based at least on the second output.08-22-2013
20090116545Adaptive Frequency Equalizer - An adaptive frequency equalization system providing an equalizer that has programmable taps that adjusts magnitude and phase of symbol information of a received signal and that provides equalized symbol information. The system includes a hard decision circuit that selects ideal symbol values using the equalized symbol information. A frequency response circuit determines frequency response update values using the ideal symbol values and the received signal. An adjust circuit updates stored frequency response information using the frequency response update values, and also updates the programmable taps of the equalizer using the stored frequency response information.05-07-2009
20110058597EQUALISATION PROCESSING - A method and apparatus for processing a signal in a wireless communication system. The method comprises: receiving a signal at a receiver over a wireless channel; sampling the signal to produce a plurality of signal samples; and supplying the samples to an equaliser implemented in software running on a processor of the receiver, the equaliser being configured to process the samples using at least one equaliser time period having a nominal length. The method further comprises dynamically determining one or more characteristics of the channel; in dependence on the determined channel characteristics, dynamically selecting between a first operational state of the equaliser in which the nominal length is used and a second operational state of the equaliser in which an alternative length is used in place of the nominal length; and processing the samples in the equaliser using the determined equaliser time period length.03-10-2011
20110058596Multi-Channel Equalization to Compensate for Impairments Introduced by Interleaved Devices - A system includes a time-interleaved device. An equalizer effectively can apply different equalization to different interleaved channels. For convenience, these equalizers will be referred to as multi-channel equalizers. In one aspect, an apparatus includes an interleaved device having M interleaved channels, and a multi-channel equalizer coupled to the interleaved device. The multi-channel equalizer is capable of applying a different equalization to different interleaved channels, thus compensating for channel-dependent impairments.03-10-2011
20100238992RADIO RECEIVING APPARATUS AND RADIO RECEIVING METHOD - In-phase channels and quadrature-phase channels of carrier waves are calculated from a reception signal obtained by receiving the multi-carrier signal. Transmission channel characteristics of the carrier waves are calculated from a known signal section of the reception signal. Transmission channel equalization processing for compensating for an amplitude change and phase rotation in the in-phase channels and the quadrature-phase channels caused by a transmission channel is performed. A region on a complex plane in which output data after transmission channel equalization is present is determined. An estimation value of a phase rotation angle used in performing the transmission channel equalization processing is corrected based on information concerning the determined region.09-23-2010
20100220780FULLY COMPENSATED ADAPTIVE INTERFERENCE CANCELLATION SYSTEM - A system for removing interference comprising a receive decimation filter that accepts a composite received baseband signal and generates filtered sampled data at a decimation rate, a transmit decimation filter that accepts a digitally converted replica of an interfering signal and generates filtered sampled data at a decimation rate, an integer sample delay control (ISDC) that provides multiple sample delay control for the replica and stores an estimated delay value, an adaptive filter that provides fractional sample delay control for the replica of the interfering signal and optimizes cancellation of the interfering signal, a digital phase-locked loop (DPLL) programmed with a known frequency offset of the interfering signal that tracks a phase and frequency of the replica of the interfering signal, an automatic gain control (AGC) that maintains near full scale operation of adaptive filtering and the DPLL, and a slicer, mixer, and delay unit forming an error estimator.09-02-2010
20100208787WAVEFORM EQUALIZER AND METHOD FOR CONTROLLING THE SAME, AS WELL AS RECEIVING APPARATUS AND METHOD FOR CONTROLLING THE SAME - The present invention relates to a waveform equalizer and a method for controlling the same, as well as a receiving apparatus and a method for controlling the same whereby better receiving characteristics are provided than before.08-19-2010
20090290630ADAPTIVE EQUALIZER WITH A DUAL-MODE ACTIVE TAPS MASK GENERATOR AND A PILOT REFERENCE SIGNAL AMPLITUDE CONTROL UNIT - An adaptive equalizer including an equalizer filter and a tap coefficients generator used to process a sample data stream derived from a plurality of received signals is disclosed. The tap coefficients generator includes an equalizer tap update unit, a vector norm square estimator, an active taps mask generator, a switch and a pilot amplitude reference unit used to minimize the dynamic range of the equalizer filter. A dynamic mask vector is used to mask active taps generated by the equalizer tap update unit when an unmasked signal output by the equalizer filter is selected by the switch to generate an error signal fed to the equalizer tap update unit. A fixed mask vector is used to mask active taps generated by the equalizer tap update unit when a masked signal output by the equalizer filter is used to generate the error signal.11-26-2009
20100260250System and Method for Transmitter Training - A system and method are provided for ordering tap setting modifications in a link partner using a plurality of voltage gain taps, while avoiding minimum and maximum limitations. Provided is a link partner (LP) transmitter having a parallel selectable voltage gain taps. The method sends messages from a network-connected local device (LD) directing the LP to generally change the gain setting of either the pre-tap or the post-tap, as follows. The gain setting of selected tap is changed in the desired direction of modification and then the center tap gain settings is maximally increased until a limit signal is received. If a selected tap increment is desired, the center tap is initially decremented more steps than the desired change in the selected tap.10-14-2010
20100027607APPARATUS FOR TIME-DOMAIN PRE-EMPHASIS AND TIME-DOMAIN EQUALIZATION AND ASSOCIATED METHODS - An integrated circuit (IC) includes a transmitter. The transmitter includes a pre-emphasis circuit. The pre-emphasis circuit pre-distorts an input signal by moving in time a sampling point of the input signal. The input signal is thus pre-distorted before transmission to a communication channel. The IC may optionally include a receiver. The receiver includes an equalization circuit. The equalization circuit equalizes a signal received from a communication channel by moving in time a sampling point of the signal received from the communication channel.02-04-2010
20100202504Channel Estimation Filter for OFDM receiver - A channel smoothing filter with a finite impulse response (FIR) has a controller which reads parallel sample data out of an FFT memory in such a manner as to generate an even function, the sample data applied to a preamble equalizer accompanied by a preamble sign and zero, the preamble outputs coupled to three filter processors, each filter processor having four filter engines whose outputs are summed, the channel smoothing filter generating an a register output, the register input coupled to a summer which has as inputs: the first filter processor shifted by four, the second filter processor shifted by two, the third filter processor, and the register output. Coefficients for an edge filter and a central filter are provided in Zero Sign Shift (ZSS) format, and by selection of coefficients using a canonical signed digit (CSD) algorithm, no multipliers are required for the channel smoothing FIR filter.08-12-2010
20090323794Transmitter Equalization Method and System - A method is provided to determine transmitter equalization coefficients and a number of transmitter equalization taps. The method may include transmitting a first signal pattern at a first frequency across a channel to a receiver and determining a first eye height of the received clock signal pattern at the receiver. The method may also include transmitting a second signal pattern at a second frequency across the channel to the receiver and determining a second eye height of the received clock signal pattern at the receiver. Transmitter equalization coefficients may then be determined based on the determined first eye height and the determined second eye height.12-31-2009
20090190646Adaptive equalizer and adaptive equalization method - An adaptive equalizer includes an adaptive filter and a control unit. The adaptive filter performs an adaptive equalization processing for an input signal so as to make an amplitude of an equalized output signal constant, the input signal being modulated by a modulation system that produces a modulation signal with constant amplitude characteristics. The control unit gradually changes equalization ability of the adaptive equalization processing of the adaptive filter in accordance with characteristics of the input signal.07-30-2009
20120195360Methods for managing alignment and latency in interference suppression - An interference cancelling receiver combines data from multiple paths after aligning to transmitter timing, and uses either an equalizer or a Rake receiver to compute symbol estimates. Interference estimates are generated from the symbol estimates, and multiple interference estimates are combined after re-aligning the interference estimates to receiver timing. At least two segments of symbol estimates are computed for each segment of interference cancelled data.08-02-2012
20120195359TRANSMITTER WITH DYNAMIC EQUALIZER - A method comprises operating a processor at a first power control strategy. Such a method further comprises determining whether a workload of a task running on a processor has fallen below a lower threshold, and changing to a second power control strategy to operate the processor based on determining that the workload of the task has fallen below the lower threshold.08-02-2012
20090110047DEMODULATOR WITH CONFIGURABLE ADAPTIVE EQUALIZER - An improved multi-channel receiver for satellite broadcast applications or the like. In an exemplary embodiment, the receiver has an adaptive equalizer configurable to operate with QPSK or 8PSK modulated signals. In the equalizer, a slicer table memory responsive to an 8-level quantizer (slicer) and a select signal is configured to map the output of the quantizer into QPSK or 8PSK symbol coordinates depending on whether the QPSK or the 8PSK signal is being received. The slicer table memory may be loaded with the symbol coordinates calculated from data in the 8PSK signal. A pattern matcher determines if the 8PSK or the QPSK signal is being received and asserts the select signal to configure the slicer table memory accordingly.04-30-2009
20090110048Radio Receiver in a Wireless Communications System - Techniques are described for optimizing the processing facilities of a receiver in a wireless communication environment, taking into account processing performance set against the computing resources and/or power consumption required to obtain that processing performance. A radio receiver for a wireless communications system can include channel equalization means arranged to receive samples of an incoming signal and to generate an equalized output, said channel equalization means including means for processing said digital samples in accordance with an equalizer algorithm. The receiver includes means for estimating parameters of a channel over which the incoming signal has been transmitted. The receiver can also include means for selecting from a plurality of equalizer algorithms an equalizer algorithm for execution by the processing means based on at least one said estimated channel parameter. Related methods and algorithms are described. Related computer program products are also described.04-30-2009
20090110046METHOD AND APPARATUS FOR EQUALIZATION USING ONE OR MORE QUALIFIERS - Methods and apparatus are provided for equalizing a received signal. A received signal is equalized by updating one or more equalization parameters; and discarding the updated equalization parameters if one or more predefined qualifier conditions are detected during the equalizing step. The received signal can optionally be equalized using the updated equalization parameters if the predefined qualifier conditions are not detected during the equalizing step. The updated equalization parameters can optionally be stored if the one or more predefined qualifier conditions are not detected during the equalizing step04-30-2009
20090110045METHOD AND APPARATUS FOR RATE-DEPENDENT EQUALIZATION - Methods and apparatus are provided fox equalizing a received signal. A received signal is equalized by determining a data rate of the received signal; obtaining one or more equalization parameters associated with the determined data rate; and equalizing the received signal using the obtained one or more equalization parameters. The equalization parameters may comprise, for example, one or more of a gain parameter, zero control for a high pass filter and one or more threshold settings for one or more latches used during the equalizing step, such as data latches or transition latches (or both).04-30-2009
20100296570SYSTEMS AND METHODS FOR MULTICARRIER MODULATION USING MULTI-TAP FREQUENCY-DOMAIN EQUALIZER AND DECISION FEEDBACK - Through the use of feedback in determining frequency domain equalization, intersymbol interference can be reduced. Specifically, the determined constellation point closest to the determined received point can be fed back to aid in determining one or more other closest constellation points.11-25-2010
20100303142System and Method for Pre and Post-Tap Zeroing - A system and method are provided for zeroing pre and post-tap settings in a link partner using a plurality of voltage gain taps. The method provides a link partner (LP) transmitter. A network-connected local device (LD) selects an LP pre-tap or post-tap. The LD also chooses a zero gain setting for the selected LP tap. In a first iteration, the LD directs the LP to decrease the difference between the selected tap gain setting and the zero setting by 1 step. If a limit signal is not received by the LD, the LP is directed to maximally increase the center tap gain setting until a limit signal is received. The iterations are continued until a limit signal is returned in response to the LD directing the LP to decrease the difference between the selected tap gain setting and the zero setting.12-02-2010
20100303143SIGNAL PROCESSING APPARATUS AND SIGNAL PROCESSING METHOD - Provided is a signal processing apparatus including: an equalizer circuit that amplifies a predetermined frequency band of an input signal and outputs an output signal; a sampler circuit that samples the output signal amplified by the equalizer circuit with the output signal being offset in an amplitude direction using a multiphase clock system; an area information calculation circuit that calculates area information of an eye opening in an eye diagram of the output signal based on the output signal sampled by the sampler circuit; and a control circuit that controls amplification of the equalizer circuit based on the area information of the eye opening calculated by the area information calculation circuit.12-02-2010
20100316110TRANSMITTING/RECEIVING SYSTEM AND METHOD OF PROCESSING BROADCAST SIGNAL IN TRANSMITTING/RECEIVING SYSTEM - A transmitting system, a receiving system, and a method of processing broadcast signals are disclosed. The receiving system includes a tuner, a channel equalizer, a storage unit, an inner decoder, a deinterleaver, an outer decoder, and an interleaver. The tuner receives a broadcast signal including a data group. The channel equalizer channel-equalizes the broadcast signal. The storage unit stores mobile service data included in the channel-equalized broadcast signal, and repeatedly outputs the stored mobile service data for a predetermined number of turbo decoding iterations. The inner decoder matches the mobile service data being outputted from the storage unit with mobile service data being outer-decoded and fed-back and inner-decodes the matched mobile service data. The deinterleaver deinterleaves the inner-decoded mobile service data in block units. The outer decoder outer-decodes the deinterleaved mobile service data. The interleaver interleaves the outer-decoded mobile service data in block units and feeding-back the interleaved mobile service data to the inner decoder.12-16-2010
20110110415MONITORING INSTABILITY AND RESETTING AN EQUALIZER - Instability resulting from non-linear impairments is detected and an equalizer of an end device is reset. An equalization instability threshold is retrieved from a data storage device. An equalization parameter for the end device is monitored and, if the equalization parameter exceeds the equalization instability threshold, the equalizer is reset.05-12-2011
20100322299METHOD AND APPARATUS FOR DETERMINING EQUALIZATION COEFFICIENTS - A system for filtering a data signal includes an input configured to receive the data signal through a transmission medium and a filter configured to remove distortion from the received data signal using equalization coefficients. The system further includes a processing unit configured to determine dynamically the equalization coefficients of the filter without using a predetermined training pattern in the received data signal.12-23-2010
20110026578METHOD FOR RECEPTION OF LONG RANGE SIGNALS IN BLUETOOTH - The invention of a method for reception of long transmission range Bluetooth signals impaired by multipath are disclosed. The new reception method proposed allows to increase the transmission range for data transmission in Bluetooth. The invention proposes the use of a new FDE adapted to SC transmission without a GI or CP. The proposed FDE very successfully mitigates ISI while being very implemention-friendly.02-03-2011
20090067484Selectable-Tap Equalizer - A signaling circuit having a selectable-tap equalizer. The signaling circuit includes a buffer, a select circuit and an equalizing circuit. The buffer is used to store a plurality of data values that correspond to data signals transmitted on a signaling path during a first time interval. The select circuit is coupled to the buffer to select a subset of data values from the plurality of data values according to a select value. The equalizing circuit is coupled to receive the subset of data values from the select circuit and is adapted to adjust, according to the subset of data values, a signal level that corresponds to a data signal transmitted on the signaling path during a second time interval.03-12-2009
20110032977Dual-Port Input Equalizer - A dual-port input equalizer includes a control unit for generating a first control signal and a second control signal according to a selection signal, a first equalizer for receiving a first and second differential voltage for equalization according to the first control signal and the second control signal, which the first equalizer includes a first transistor, a second transistor, an passive loading portion, and a first zero-point generation circuit, a second equalizer for receiving a third and fourth differential voltage for equalization according to the first control signal and the second control signal, which the second equalizer includes a third transistor and a fourth transistor, which the drain of the first transistor, the second transistor, third transistor, and the fourth transistor coupled to the passive loading portion, and the source of the first transistor, the second transistor, third transistor, and the fourth transistor coupled to the first zero-point generation circuit.02-10-2011
20090034602FILTER WEIGHT ESTIMATION DEVICE WITH UPDATE AT HSDSCH SYMBOL RATE, FOR A SYMBOL LEVEL EQUALISER - A filter weight estimation device (D), for an equaliser of a communication receiver, comprises i) a tap delay line connected to N branches each comprising a descrambler (DS02-05-2009
20090034601ADAPTIVE EQUALIZATION SYSTEM AND METHOD HAVING A LOCK-UP-FREE QUANTIZED FEEDBACK DC RESTORATION CIRCUIT - An adaptive equalizer may include one or more equalizing gain stages coupled to an input signal. An automatic gain control circuit may be used to control the gain of the one or more equalizing gain stages, the automatic gain control circuit having an AGC reference input. A dual-output DC restoration circuit may be coupled to the output of the one or more equalizing gain stages for generating a first output signal using a first hysteresis slicer that DC restores the input signal and for generating a second output signal using a second hysteresis slicer that is coupled to the AGC reference input of the automatic gain control circuit, wherein the second hysteresis slicer introducing less hysteresis than the first hysteresis slicer.02-05-2009
20110044383MIMO RECEIVING APPARATUS AND METHOD - A coherent bandwidth calculation unit (02-24-2011
20110243214INDUCING RESPONSE SIGNATURES IN A COMMUNICATION NETWORK - Methods and systems are provided in which a network induces different distortions in signals traversing different segments of the network. The distortions may be used to identify locations on the network of devices that transmit and receive the signals. The distortions may be reflected in equalization coefficients programmed into transmitting or receiving devices, which may be used to pre or post filter the signals to compensate for the distortions.10-06-2011
20110243213Receivers for Processing Vestigial Sideband Signals and Processing Methods Thereof - Provided is a receiver for processing VSB signal. The receiver includes a first equalizer/decoder unit and a second equalizer/decoder unit. The first equalizer/decoder unit performs a first equalizing operation, first TCM decoding and first RS decoding on a received symbol to output a first dibit. The second equalizer/decoder unit performs a second equalizing operation, second TCM decoding and second RS decoding on the received symbol to output a transport stream. The first dibit is provided as a priori information for a soft-decision operation of the second TCM decoding.10-06-2011
20120243598Methods and Systems for Adaptive Receiver Equalization - Methods and systems for adaptively equalizing an analog information signal for a signal path, including sampling the analog information signal, thereby generating analog samples, and performing an equalizing process on the analog samples, wherein the equalizing includes processing an average of post-transition sample amplitudes and an average of steady state sample amplitudes of the analog samples to produce equalized analog samples.09-27-2012
20100226423METHOD AND APPARATUS FOR EQUALIZATION IN CLUSTERED CHANNELS - This invention relates to an equalization apparatus and an equalization method. A plurality of equalizers is applied to the equalization apparatus to eliminate interferences of multiple clusters in a channel. The weights of the equalizers are calculated under minimum mean square error criterion by gains of delay paths of multiple clusters in the whole channel. Therefore, the interference of different clusters in the whole channel can be greatly eliminated.09-09-2010
20120134406Communication System and Method for Cancelling Timing dependence of Signals - In a communication system, a timing-dependence cancelling module is included for cancelling timing-dependence of a transmission signal, so as to render a timing-dependent signal be capable of being utilized on communication systems. Besides, updating an echo cancelling parameter by applying an error difference variable and a data difference variable, or by directly decreasing a step-size coefficient, may also fulfill the purpose of reducing or eliminating timing dependence in a transmission signal of a communication system.05-31-2012
20110243212APPARATUS AND METHODS FOR PROCESSING A VESTIGIAL SIDEBAND SIGNAL USING A SECTIONALIZING ADAPTIVE EQUALIZER - A symbol sequence corresponding to a vestigial sideband (VSB) signal is divided into a plurality of sections, respective ones of which correspond to respective time periods. Individual ones of the sections are recursively adaptively equalized to produce respective equalized sections. A bit stream is constructed from the equalized sections.10-06-2011
20110085591RECEIVING DEVICE AND METHOD OF MOBILE COMMUNICATION SYSTEM - An apparatus and a method for generating statistical signals having a characteristic similar to an input signal of a receiving apparatus to determine an optimized filter coefficient through an adaptive equalization algorithm are provided. The apparatus includes a channel estimator, a statistical signal generator, and an adaptive algorithm processor. The channel estimator estimates a channel of a reception signal. The statistical signal generator generates a plurality of signals having the same characteristic as that of a reception signal using a channel determined through a channel estimation process. The adaptive algorithm processor performs an adaptive equalization algorithm using the plurality of generated signals to determine an optimized filter coefficient.04-14-2011
20090323795EQUALIZING STRUCTURE AND EQUALIZING METHOD - An equalizing structure and method for a wireless communication system receiving device, in which two or more transmit signals transmitted in parallel from one or more transmitters are received in received signal vectors representing two or more received data streams, the signals including information modulated onto carrier signals according to a modulation scheme, all possible transmit signals being represented by candidate constellation values in the signal constellation of the modulation scheme. A processor calculates an estimate for a constellation value of a received signal and determines a number of candidate constellation values in the vicinity of the estimated constellation value in the signal constellation. A metric value calculator calculates metric values based on the received signal vectors and the product of channel estimation values with candidate signal vectors, each candidate signal vector including a candidate constellation value for each of the two or more transmit signals, wherein the metric values are calculated for each constellation value of the number of candidate constellation values and the estimated constellation value. A maximum likelihood detector detects one of the candidate signal vectors having a minimum Euclidean distance to a respective receive signal vector as a most likely transmit signal vector based on the metric values.12-31-2009
20100054322CHANNEL ESTIMATION AND EQUALIZATION FOR HARD-LIMITED SIGNALS - The present invention provides a method and apparatus for channel estimation when the amplitude of a received signal is hard-limited. A channel estimator computes amplitude estimates for the received signal based on the phase samples of the received signal and previous channel estimates. The amplitude estimates may comprise the expected values of the amplitude given the phase samples and the initial channel estimates. The channel estimator then computes revised channel estimates based on the amplitude estimates and the phase samples. The process may be performed iteratively to refine the channel estimates during each iteration.03-04-2010
20100061439COMMUNICATION SYSTEM, APPARATUS AND METHOD - A system and method for communication along a track implementing a channel equalizer is disclosed. The signaling system includes a track having a pair of rails spaced apart in a parallel orientation and a first signaling point electrically connected to the track. A second signaling point is electrically connected to the track and separated from the first signaling point such that the first and second signaling points are capable of communicating track data therebetween. The second signaling point includes therein a channel equalizer configured to filter the track data received from the first signaling point.03-11-2010
20100135376RECEIVING APPARATUS AND METHOD FOR RECEIVING SIGNALS IN A WIRELESS COMMUNICATION SYSTEM WITH IMPROVED EQUALIZATION PERFORMANCE - The present invention relates to a receiving apparatus (06-03-2010
20100128773COMMUNICATION APPARATUS AND SIGNAL PROCESSING METHOD - A communication apparatus includes a signal detector that detects incoming (i.e., receives) information from a signal received wirelessly. The signal detector includes a wave detector, an equalizer, and a detector. The wave detector accepts an incoming signal wherein information is modulated onto a carrier signal, analyzes the envelope variation of the incoming signal, and generates a detection signal containing the incoming information. The equalizer corrects the detection signal and outputs a corrected detection signal. The detector then detects the incoming information from the corrected detection signal.05-27-2010
20090028233METHOD AND DEVICE FOR ADAPTING A SIGNAL - A method and device for adapting a signal is provided. The signal includes a number of recurring samples of data. In one example embodiment, the method receives recurring samples of data. Each of the samples of data includes a first number of elements. A second number of elements are selected from at least one of the recurring samples. The second number of elements is approximately less than the first number of elements. The selected second number of elements are substituted with respective phase altered elements. The subject matter also provides a method and device for identifying a signal property(ies) and a computer system for implementing these methods.01-29-2009
20090213921CARRIER RECOVERY SYSTEM AND CARRIER RECOVERY METHOD - The invention provides carrier recovery systems and carrier recovery methods. The carrier recovery system comprises a compensation signal generator, a compensation device and a mode selector. The compensation signal generator generates a compensation signal based on a coherent demodulated signal. In a first mode, the compensate device is couple behind an equalizer; the coherent demodulated signal is generated by the compensation device which compensates the output of the equalizer with the compensation signal. In a second mode, the compensate device is coupled prior to the equalizer, compensating the output of a synchronizer with the compensation signal to generate the input of the equalizer. In the second mode, the compensation signal generator receives the output of the equalizer as the coherent demodulated signal. The mode selector switches the carrier recover system from the first mode to the second mode when an estimated frequency offset satisfies a first criterion.08-27-2009
20110069749NONLINEAR EQUALIZER TO CORRECT FOR MEMORY EFFECTS OF A TRANSMITTER - Techniques for correcting for memory effects of a transmitter are described. In an exemplary design, a receiver obtains input samples including a desired signal transmitted by a transmitter having memory effects. The receiver performs nonlinear equalization on the input samples to obtain first equalized samples, performs linear equalization on the input samples to obtain second equalized samples, and determines output samples based on the first and second equalized samples. The nonlinear equalization corrects for the memory effects and nonlinearities of the transmitter and possibly nonlinearities and memory effects of the receiver. The receiver may jointly determine coefficients for both linear and nonlinear equalization based on an adaptive algorithm. The receiver processes (e.g., demodulates and decodes) the output samples to recover data sent in the desired signal by the transmitter.03-24-2011
20120201288Adaptive Equalization and Interference Cancellation with Time-Varying Noise and/or Interference - A method and apparatus is disclosed to compensate for interference and/or distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. A communications receiver includes a noise analyzer to characterize the composition of the interference and/or the distortion and produce a selection signal indicating the composition of the interference and/or the distortion. The communications receiver selects at least one set of equalization coefficients and/or updates at least one parameter of a least-squares algorithm or the suitable equivalent algorithm to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of a particular time-varying noise and/or interference condition.08-09-2012
20120201287COMMUNICATION DEVICE AND METHOD OF SETTING COMMUNICATION DEVICE - A communication device includes multiple paths that are provided in the device and transmit signals; an adjuster that adjusts transmission characteristics to be a favorable state by adjustment of the waveform of the signals on the paths; and a controller that controls the adjustment of the transmission characteristics of the paths by the adjuster, identifies other path(s) that affects a path to be adjusted, and controls suppression of crosstalk due to the other path(s).08-09-2012
20110150070METHOD AND SYSTEM FOR PROCESSING MULTIPATH SIGNALS OVER A SINGLE USER DOWNLINK MIMO CHANNEL USING A HYBRID EQUALIZER/RAKE RECEIVER - A mobile device comprises multiple receive antennas to receive spatially independent multipath signals from multiple transmit antennas located on a single base station. The mobile device concurrently generates a RAKE-based equivalent single path signal (RAKE ESPS) and an equalizer-based equivalent single path signal (equalizer ESPS) for the multipath signals received via each receive antenna. The generated RAKE ESPS or the generated equalizer ESPS is selected for channel decoding. Reference signal components are extracted from the multipath signals received to determine noise components, which is used to determine signal quality information of the generated RAKE ESPS and the generated equalizer ESPS. A final ESPS is selected from the generated RAKE ESPS and the generated equalizer ESPS based on the corresponding determined signal quality information. The selected final ESPS is diversity processed by combining signal components over the transmit/receive antennas. Transmission parameters are determined for channel decoding the combined signals.06-23-2011
20110026577Equalization for OFDM Communication - The problem of inefficient channel impulse-response processing is addressed by processing different parts of a channel impulse response to accurately locate channel taps, and to generate more than one set of equalization coefficients. This allows the most-suited equalization coefficient to be selected based on a selection criterion.02-03-2011
20100260251RADIO COMMUNICATION SYSTEM, RECEPTION DEVICE, AND RECEPTION METHOD - A reception device which receives a signal transmitted by a transmission device that changes at least one of a modulation scheme and a coding rate based on information reported from the reception device, the reception device includes an equalization unit which equalizes a received signal in a frequency domain, a signal-noise ratio measuring unit which measures a signal-noise ratio from the received signal after equalization, and a notification signal generation unit which sets at least one of a modulation scheme and a coding rate from the quality of reception and generates a signal to be reported to the transmission device.10-14-2010
20100098146CHANNEL ESTIMATION METHOD AND DEVICE IN WIRELESS COMMUNICATION SYSTEM - Provided is a channel estimation method and device in a wireless communication system. A channel estimating device for estimating a channel based on a received signal generates an initial channel estimate by using a preamble extracted from the received signal, and determines whether there is a midamble between data symbols appearing next to the preamble. When there is a midamble, the channel estimating device acquires a first channel estimate by using the midamble, and acquires an updated second channel estimate by using the initial channel estimate and the first channel estimate. The channel estimating device performs channel equalization with the second channel estimate to compensate distortion.04-22-2010
20100098145APPARATUS AND METHOD FOR CHANNEL ESTIMATION IN MOBILE COMMUNICATION SYSTEM - An apparatus and method for reducing power consumption of a receiver of a mobile communication system are provided. The apparatus includes an adaptive multi-tap segment channel estimator for determining a segment size according to a delay spread value for each channel tap, for determining a channel estimation frequency by determining a sum of segment block energy, and for allocating each segment to the channel estimator.04-22-2010
20120033724METHOD AND SYSTEM FOR SELECTIVE EQUALIZATION ENABLEMENT BASED ON MODULATION TYPE - Aspects of a method and system for selective equalization enablement based on modulation type may be found in a method for processing radio frequency (RF) signals received via a RF channel, detecting a modulation type of at least a portion of the received RF signals, and determining whether to enable or disable an equalization circuit for processing at least a subsequent portion of the received RF signals based on the detected modulation type; and selecting one of a plurality of inputs to a selector based on the detected modulation type, wherein the plurality of inputs comprise the at least a subsequent portion of the received signals and an output signal generated by the equalization circuit.02-09-2012
20110211630INTER-CARRIER INTERFERENCE REMOVAL DEVICE AND RECEPTION DEVICE USING THE SAME - An inter-carrier interface removal device can improve estimation accuracy of inter-carrier interference caused by Doppler shift in a received multi-carrier signal moving at a high speed, and a reception characteristic of the multi-carrier signal after removing the inter-carrier interference. The inter-carrier interference removal device includes a channel estimation unit estimating a channel frequency characteristic according to a carrier signal, an equalization unit equalizing the carrier signal with the channel frequency characteristic and outputs tentative carrier data, a reliability value calculation unit calculating a reliability value according to the channel frequency characteristic, a weighting unit weighting the tentative carrier data with the reliability value, an ICI component estimation unit estimating an ICI component according to the weighted tentative carrier data and the estimated channel frequency characteristic, and an ICI removal calculation unit removing the ICI component from the carrier signal.09-01-2011
20110255587RECEPTION DEVICE AND SCRAMBLING CODE DECODING METHOD - A reception device includes: a channel estimation circuit to receive a first signal scrambled by one of N scrambling codes and transmitted through M carriers having different frequencies, and calculate N channel estimation values corresponding to N types of first specified signals based on the first signal, where N is an integer greater than or equal to 2, where M is an integer greater than or equal to 2; a channel equalization circuit to channel-equalize a second signal, which is transmitted using the one of N scrambling codes and the M carriers, based on the N channel estimation values; and a scrambling code decoding circuit to evaluate (N*M) equalized second signals based on N types of second specified signals and decode a scrambling code of the second signal from among the N scrambling codes.10-20-2011
20100309969TRANSMITTING/RECEIVING SYSTEM AND METHOD OF PROCESSING BROADCAST SIGNAL IN TRANSMITTING/RECEIVING SYSTEM - A receiving system and a method of processing broadcast signals in the receiving system are disclosed. The receiving system includes a tuner, a known sequence detector, a carrier recovery unit, a baseband processor, and a channel equalizer. The tuner receives a broadcast signal of a passband including a data group. Herein, the data group comprises mobile service data, a plurality of known data sequences, and signaling data. The known sequence detector estimates an initial frequency offset and detects a position of each known data sequence based on the known data sequence having the first data pattern. The carrier recovery unit acquires an initial frequency synchronization using the initial frequency offset estimated by the known sequence detector and estimates a residual frequency offset based upon the known data sequences having the second data pattern so as to perform carrier recovery. The baseband processor performs complex multiplication between the received broadcast signal and an output of the carrier recovery unit, thereby converting the passband broadcast signal to a baseband broadcast signal.12-09-2010
20080253438Near-Minimum Bit-Error Rate Equalizer Adaptation - Method for equalizer adaptation and/or target adaptation in a receiver for a transmission channel. The method provides for detecting data in the received signal, deriving an error sequence representing potential errors in the data detection, deriving a first value representing the likelihood of an error in the data detection, the first value based on the error sequence and the received signal, and enabling and disabling adaptation of the equalizer and/or the target response depending on the first value being below or above a predefined threshold value.10-16-2008
20080205503Adaptive equalizer with tap coefficient averaging - In one embodiment, a receiver has an equalizer, a tap-averaging block, a delay buffer, and a filter. The equalizer receives an input signal from upstream processing and generates sets of filter coefficients. Each set of filter coefficients is adaptively generated by 1) filtering the received signal to generate an equalized signal, 2) calculating an error of the equalized signal, and 3) generating a new set of coefficients based on the error of the equalized signal. The sets of filter coefficients are output to the tap-averaging block, which averages groups of the sets of filter coefficients to generate sets of averaged filter coefficients, where each averaged set is output to the filter. The filter receives a time-delayed version of the input signal from the delay buffer and applies the current set of averaged filter coefficients to the time-delayed signal. The filtered signal is then output to downstream processing.08-28-2008
20100329325Statistically-Adapted Receiver and Transmitter Equalization - In described embodiments, adaptive equalization of a signal in, for example, Serializer/De-serializer transceivers by a) monitoring a data eye in a data path with an eye detector for signal amplitude and/or transition; b) setting the equalizer response of at least one equalizer in the signal path while the signal is present for statistical calibration of the data eye; c) monitoring the data eye and setting the equalizer during periods in which received data is allowed to contain errors (such as link initiation and training periods) and periods in which receive data integrity is to be maintained (such as normal data communication).12-30-2010
20110134989RADIO COMMUNICATION APPARATUS AND CONTROL METHOD - A radio base station (06-09-2011
20120147943Method and Apparatus for Complex In-Phase/Quadrature Polyphase Nonlinear Equalization - Complex polyphase nonlinear equalizer (cpNLEQs) mitigate nonlinear distortions generated by complex in-phase/quadrature (I/Q) time-interleaved analog-to-digital converters (TIADCs). Example cpNLEQs upsample the digital waveform emitted by the TIADC, e.g., by a factor of two, then separate the upsampled digital waveform into upsampled in-phase and quadrature components. Processors in the cpNLEQs create real and imaginary nonlinear compensation terms from the upsampled in-phase and quadrature components. The nonlinear compensation terms are downsampled, and the downsampled imaginary nonlinear compensation term is phase-shifted, then combined with the downsampled real component to produce an estimated residual distortion. Subtracting the estimated residual distortion from the digital waveform emitted by the TIADC yields an equalized digital waveform suitable for further processing.06-14-2012
20080219343SYSTEMS AND METHODS FOR PROCESSING A SIGNAL WITHIN A COMMUNICATIONS SYSTEM WITH A SUPERIMPOSED REFERENCE SIGNAL - A method for processing a signal within a communications system is described. A signal transmitted over a channel is received that includes an information signal and a reference signal. The information signal includes data. The reference signal is superimposed on the data. A channel impulse response of the channel is estimated based on the reference signal. The information signal is equalized based on the estimation of the channel impulse response by compensating the signal, estimating the information signal, canceling the reference signal and recovering the data.09-11-2008
20110075720Radio Receiver Having a Multipath Equalizer - A radio receiver has a multipath equalizer that includes a filter and a coefficient estimator. The filter provides a reconstructed signal by applying a transfer function including a reflection coefficient and a delay coefficient to a multipath radio signal. The coefficient estimator adapts the reflection coefficient and the delay coefficient in response to a deviation in magnitude of the reconstructed signal from a normalized value. In one form, the coefficient estimator adapts at least one of the reflection coefficient and the delay coefficient by estimating a partial derivative using a predetermined number of terms. In another form, the coefficient estimator acquires an initial value of the delay coefficient by determining a global minimum as a lowest one of a plurality of local minimums, each determined using a plurality of values of the delay coefficient, and selecting the initial value of the delay coefficient as its value at the global minimum.03-31-2011
20110075718Automatic Filter-Reset Mechanism - In one embodiment, a (hard-drive) read channel has a (DFIR equalization) filter, whose tap coefficients are adaptively updated. A reset controller monitors an (LLR) signal generated downstream of the filter to automatically determine when to reset the filter, e.g., by reloading an initial set of user-specified tap coefficients. For LLR values, the reset controller determines to reset the filter when the reset controller detects that too many recent LLR values have confidence values that are too low. When implemented in a hard-drive read channel, the reset controller can reset the filter one or more times during read operations within a sector of the hard drive.03-31-2011
20100254446RECEIVER AND METHOD FOR TWO-STAGE EQUALIZATION WITH SEQUENTIAL SEARCH - A receiver and method are described herein that address inter-symbol interference in a received signal by using a two-stage equalizer which includes a first demodulation stage that processes the received signal and produces initial symbol decisions, and a non-linear equalization second stage that uses the received signal to perform a sequential search in an attempt to improve upon the initial symbol decisions where if able to improve upon the initial symbol decisions then an output sequence is obtained from the sequential search and if not able to improve upon the sequence metric threshold then the output sequence is the initial symbol decisions.10-07-2010
20100215091Adaptive Equalization Using Correlation of Edge Samples With Data Patterns - An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.08-26-2010
20100142607Methods and Systems for Transmitting Data by Modulating Transmitter Filter Coefficients - A signaling system supports main and auxiliary communication channels between integrated circuits in the same direction over a single link. An equalizing transmitter applies appropriate filter coefficients to minimize the impact of intersymbol interference when transmitting the main data over a communication channel. The transmitter modulates at least one of the filter coefficients with the auxiliary data to induce apparent ISI in the transmitted signal. A main receiver ignores the apparent ISI to recover the main data, while an auxiliary receiver detects and demodulates the apparent ISI to recover the auxiliary data. The auxiliary data may be encoded using spread-spectrum techniques to reduce the impact of the auxiliary data on the main data.06-10-2010
20100195710RECEIVING APPARATUS WITH FREQUENCY DOMAIN EQUALIZER - The present invention relates to a receiving apparatus (08-05-2010
20100040129CHANNEL EQUALIZATION AND CARRIER RECOVERY METHOD AND RECEIVER IN HIGH SPEED WIRELESS COMMUNICATION SYSTEM - Provided are a channel equalization and carrier recovery method and a receiving apparatus thereof. In the method, a receiver of the high speed wireless communication system obtains an initial value of a channel equalization coefficient through non-causal channel estimation in a frequency domain during a preamble transmission section of a packet. High-order QAM signal correction for updating the channel equalization coefficient in a time domain is performed during a data transmission section of the packet. when a payload section starts in the data transmission section of the packet, channel equalization coefficient tracking is performed on the basis of frequency domain decision, and a hard decision of a correction value by the high-order QAM signal correction in the time domain is made to correct carrier phase errors, so that the channel equalization coefficient is updated.02-18-2010
20110051798EQUALIZER CIRCUIT - An equalizer circuit receives digital amplitude data A[N] which represents the amplitude level of the N-th (N is a nonnegative integer) signal to be transmitted via a transmission line and timing data T[N] which represents the cycle of the signal, and performs waveform shaping. The equalizer circuit includes: M (M is an integer) calculation units ECU03-03-2011
20110051797Method and apparatus for receiving signal in wireless communication system - A mobile terminal includes a channel estimation module that is maintained in an active state. A controller determines an activation time point of an equalizer weight calculation module for calculating a tap coefficient. The activation time point is earlier than an activation time point of a main equalizer module, and activates the equalizer weight calculation module at the activation time point so as to calculate the tap coefficient. When the equalizer weight calculation module's operation is completed, the controller activates the main equalizer module, detects a mobile terminal ID, activates an interference cancellation module, and controls the main equalizer module to provide a data signal demodulator with the data signal compensated for by the tap coefficient. A demodulator demodulates the compensated data signal.03-03-2011
20110051796EQUALIZATION AND RESIDUAL SELF-INTERFERENCE SUPPRESSION USING SERIAL LOCALIZATION WITH INDECISION - A constellation processing module of a receiver groups points of a constellation associated with a transmitted signal into a plurality of subsets. At least two adjacent ones of the subsets have one or more common constellation points so that the at least two adjacent subsets overlap. The constellation processing module also determines a centroid-based value for each of the subsets of constellation points. A non-final equalization stage localizes a search for a final symbol decision using a set of the centroid-based values as constellation points. An interference suppresser suppresses residual self-interference which arises from using the set of centroid-based values as constellation points to localize the search for the final symbol decision instead of the constellation points used to modulate the transmitted signal. A final equalization stage determines the final symbol decision using a subset of the constellation points used to modulate the transmitted signal.03-03-2011
20110051795EQUALIZATION USING SERIAL LOCALIZATION WITH INDECISION - A receiver includes a constellation processing module and a plurality of equalization stages. The constellation processing module groups points of a constellation associated with a transmitted signal into a plurality of subsets. At least two adjacent ones of the subsets have one or more common constellation points so that the at least two adjacent subsets overlap. The constellation processing module also determines a centroid-based value for each of the subsets of constellation points and groups the centroid-based values into one or more sets. Each of the equalization stages except for a the last equalization stage localizes a search for a final symbol decision using the set of centroid-based values input to or selected by the equalization stage as constellation points. The last equalization stage determines the final symbol decision using the subset of constellation points input to or selected by the last equalization stage.03-03-2011
20110188564DIGITAL ADAPTATION CIRCUITRY AND METHODS FOR PROGRAMMABLE LOGIC DEVICES - Equalization of an incoming data signal can be controlled by sampling that signal at times when data values in that signal should be stable (“data samples”) and when that signal should be in transition between successive data values that are different (“transition samples”). A transition sample that has been taken between two successive differently valued data samples is compared to a reference value (which can be one of those two data samples). The result of this comparison can be used as part of a determination as to whether to increase or decrease equalization of the incoming data signal.08-04-2011
20110188563METHOD AND ARRANGEMENT IN A TELECOMMUNICATION SYSTEM - By exploiting the multi-block structure of the used slot format having a training sequence in the time domain and at least one pre-coded user data block to sequentially reconstruct the slot, using in the first act known symbols and using detected symbols in each subsequent act and improved receiver may be provided. This may result in less ISI/IBI and therefore increased performance.08-04-2011
20120069891Systems and Methods for Filter Constraint Estimation - Various embodiments of the present invention provide systems and methods for calibrating a data processing circuit. For example, a method for calibrating a data processing circuit is discussed that includes providing a digital filter, providing a detector circuit, and providing an analog filter. Operation of the digital filter is at least in part governed by filter taps that correspond to a filter tap constraint value. Operation of the detector circuit is at least in part governed by a target parameter. Operation of the analog filter is at least in part governed by an analog parameter that is one of a plurality of analog parameters. The methods further include selecting a target parameter, and calculating the filter tap constraint value based on the target parameter. Combinations of the target parameter, the calculated filter tap constraint value, and each of the plurality of analog parameters are applied to identify the analog parameter.03-22-2012
20090185611Method for calculating filter coefficients for an equaliser in a communication receiver using hermitian optimisation - A method for calculating filter coefficients for an equaliser in a communication receiver, the method including the steps of calculating (07-23-2009
20090052515Method and apparatus for calibrating equalizers without knowledge of the data pattern being received - A method and apparatus for calibrating an equalizer. The method comprises the steps of defining one or more equalization parameters and calculating a bit error rate of a signal for one or more values of a first of the one or more equalization parameters by counting at least one of running disparity errors and incorrect symbol errors. A value for the first of the one or more equalization parameters which provides the lowest bit error rate is set.02-26-2009
20120147944HIGH RESOLUTION OUTPUT DRIVER - High resolution output drivers having a relatively small number of sub-driver branches or slices each having nominal impedances substantially larger than a quantization step and that incrementally differ from one another by an impedance step substantially smaller than a quantization step. In one implementation, such “differential” or “non-uniform” sub-driver slices implement respective elements of an n choose k equalizer, with each such differential sub-driver slice being implemented by a uniform-element impedance calibration DAC. In another implementation, each component of a uniform-slice equalizer is implemented by a differential-slice impedance calibration DAC, and in yet another implementation, each component of a differential-slice equalizer is implemented by a differential-slice impedance calibration DAC. In an additional set of implementations, equalization and impedance calibration functions are implemented bilaterally in respective parallel sets of driver branches, rather than in the nested “DAC within a DAC” arrangement of the hierarchical implementations. Through such bilateral arrangement, multiplication of the equalizer and calibrator quantizations is avoided, thereby lowering the total number of sub-driver slices required to meet the specified ranges and resolutions.06-14-2012
20100080277USING CONJUGATE GRADIENT METHOD TO CALCULATE FILTER COEFFICIENT FOR TIME DOMAIN EQUALIZER - A method used in a time domain equalizer is provided. A method comprising the steps of: providing a time domain equalizer comprising a feed forward equalizer and a feedback equalizer; and using a conjugate gradient iteration in order to calculate a set of coefficients of the time domain equalizer.04-01-2010
20090092181SCALING EQUALIZER COEFFICIENTS AFTER AUTOMATIC GAIN CONTROLLER GAIN ADJUSTMENTS - In one embodiment, a receiver comprises an automatic gain controller (AGC), an equalizer, a controller, and a register interface. The AGC makes gain adjustments to compensate for changes in the average amplitude of a received signal. The equalizer has a coefficient updater that calculates coefficients and a finite impulse response (FIR) filter that applies the coefficients to the received signal to generate an equalized signal. During gain adjustments by the AGC, the register interface provides a weight freeze signal to the coefficient updater, which subsequently freezes the updating of the coefficients for a freeze duration period. Then, register interface provides a scaling factor, generated by the controller based on the size of the gain adjustment, to the coefficient updater. At the end of the freeze period, coefficient updater applies the scaling factor to the coefficients and unfreezes the coefficient updating.04-09-2009
20110305271High-Speed Signaling Systems With Adaptable Pre-Emphasis and Equalization - A signaling system includes a pre-emphasizing transmitter and an equalizing receiver coupled to one another via a high-speed signal path. The receiver measures the quality of data conveyed from the transmitter. A controller uses this information and other information to adaptively establish appropriate transmit pre-emphasis and receive equalization settings, e.g. to select the lowest power setting for which the signaling system provides some minimum communication bandwidth without exceeding a desired bit-error rate.12-15-2011
20110305270METHODS FOR OBTAINING A SET OF PATH METRICS AND EQUALIZER FOR A RECEIVER FOR DIGITAL DATA - This invention relates to methods for obtaining a bin number of path metrics. When performing such methods, a histogram is provided, which comprises a bin number of values, a maximum value and a tail region left or right of the maximum value. A bin number of path metrics is obtained from said values. According to an embodiment a local extremum is removed from said tail region. According to another embodiment the tail region is forced to be convex. According to a further embodiment a maximum metric difference between neighboring metrics is ensured.12-15-2011
20120039381Adaptive equalization system and method - An adaptive equalization system includes an equalizer, a common-mode extraction buffer unit, a low-pass filter unit, a first and second energy compare units, a current comparator, and a digital control unit. The common-mode extraction buffer unit transmits a full spectral energy of an input signal received by the equalizer to the first energy compare unit and the low-pass filter unit, and extracts a common-mode signal of the input signal to the second energy compare unit. The first and second energy compare units respectively output a current signal characterized by the high-frequency energy and a current signal characterized by the low-frequency energy to the current comparator. Based on the compare result outputted by the current comparator, the digital control unit outputs an equalization control signal to the equalizer. The adaptive equalization system has the simple structure, and reduces the power consumption, the area and the manufacturing cost of the chip.02-16-2012
20120039380METHOD AND APPARATUS FOR ITERATIVE TIMING AND CARRIER RECOVERY - Method and apparatus for iterative timing recovery for FTN signaling are provided. The iterative timing recovery method and apparatus uses a feedback timing error signal from a forward error correction block with an additional equalizer prior to a maximum a posteriori (MAP) decoder which matches the equalized FTN signal to a truncated inter-symbol interference (ISI) target. A timing error is then generated using a modified M&M timing error detector.02-16-2012
20120099637SYSTEMS AND METHODS FOR PERFORMING DYNAMIC CHANNEL ESTIMATION - Systems and methods are disclosed for dynamic channel estimation in a digital receiver by performing a dynamic equalization on an incoming signal to compensate for channel distortion; independently estimating one or more channel parameters for the dynamic equalization, wherein the one or more channel parameters track channel change; determining a convolution of the channel parameters and updating the parameters for the dynamic equalization for subsequent processing of incoming signal; and providing an equalized output from the digital receiver.04-26-2012
20090219983DATA COMMUNICATION CIRCUIT WITH EQUALIZATION CONTROL - An adaptive equalizer comprises an adjustable equalizer circuit that allows to enhance the frequency dependence of contents of the transmitted signals which suffer from losses in the connected transmission channel. A blind equalization tuning procedure is proposed that operates without knowledge about the characteristic of transmission channel. Phase positions of transitions in the equalized signal are detected. A digital post-processing circuit evaluates a measure for spread of the detected phase positions of transitions, accumulated over a plurality of the symbol periods. The digital post-processing circuit controls the adjustable equalizer, setting the adjustable equalizer to a setting wherein the detected spread is minimized.09-03-2009
20110064128RECEIVING DEVICE AND CHANNEL ESTIMATION METHOD - Disclosed are a receiving device and a channel estimation method that are capable of using the amplitude information of a received signal to perform proper channel estimation. In the device, a detection section (03-17-2011
20110317751ADAPTIVE EQUALIZER FOR HIGH-SPEED SERIAL DATA - An adaptive equalizer for high-speed serial data comprises a programmable equalizer for equalizing an input serial data signal to generate an equalized serial data signal, wherein the equalization is based on an optimal equalization mode; a signal quality meter for computing an eye width indication based on the equalized serial data signal, wherein the eye width indication is an indicative of the quality of the equalized serial data signal; and a decision unit for determining the optimal equalization mode based on the eye width indication.12-29-2011
20110317753EQUALIZERS - Methods and apparatus adapting equalizers for compensating for signal distortion of a received digital signal are disclosed. The method comprises deriving equalizer settings for a received signal, determining at least one signal parameter of said received signal; and storing the derived equalizer settings together with an indication of the signal parameter. The signal parameter could, for instance, comprise the data rate of the signal. If the signal parameter changes the equalizer is configured to use any stored settings which are appropriate for the new signal parameter. Thus, rather than start an entirely new equalizer adaptation routine every time the signal parameter changes the equalizer will use any stored settings which are appropriate for the changed parameter.12-29-2011
20110090946EQUALIZER IN A WIRELESS COMMUNICATION SYSTEM - Techniques for performing equalization at a receiver are described. In an aspect, equalization is performed by sub-sampling an over-sampled input signal to obtain multiple sub-sampled signals. An over-sampled channel impulse response estimate is derived and sub-sampled to obtain multiple sub-sampled channel impulse response estimates. At least one set of equalizer coefficients is derived based on at least one sub-sampled channel impulse response estimate. At least one sub-sampled signal is filtered with the at least one set of equalizer coefficients to obtain at least one output signal. One sub-sampled signal (e.g., with largest energy) may be selected and equalized based on a set of equalizer coefficients derived from an associated sub-sampled channel impulse response estimate. Alternatively, the multiple sub-sampled signals may be equalized based on multiple sets of equalizer coefficients, which may be derived separately or jointly. The equalizer coefficients may be derived in the time domain or frequency domain04-21-2011
20110317752EQUALIZER ADAPTATION - This invention relates to methods and apparatus for equalizer adaptation for compensating for channel distortion on received data signals. The method comprises, for each bit, forming an adjusted bit signal comprising a weighted contribution from at least one other bit period. The polarity of the adjusted bit signal is determined and the bit is categorized as a hard, i.e. high confidence, bit is the bit is above an upper threshold or below a lower threshold or otherwise is categorized as a soft bit. The weightings are adjusted based on the category of the bit wherein a first adjustment is made it the bit is categorized as a soft bit but a second, different adjustment is made if the bit is categorized as a hard bit. For a soft bit the weightings may be increased for bits which have the same polarity as the bit in question and decreased for bits of opposite polarity. For a hard bit the adjustment may increase the weighting for bits of opposite polarity and decrease the weighting for bits of the same polarity as the bit in question. The adjustments for the hard and soft bits may be weighted differently according to the proportion of soft to hard bits.12-29-2011
20120002712EQUALIZER AND EQUALIZATION METHOD - A linear equalizer unit sequentially subjects a signal to be processed to linear equalization. A temporary decision unit sequentially subjects a signal subjected to linear equalization by the linear equalizer unit to temporary decision. A nonlinear equalizer unit derives a plurality of coefficients using a signal subjected to temporary decision as a teacher signal and sequentially subject a signal subjected to linear equalization by the linear equalizer unit to nonlinear equalization based on the plurality of coefficients.01-05-2012
20120002711METHOD AND SYSTEM FOR ADAPTIVE TONE CANCELLATION FOR MITIGATING THE EFFECTS OF ELECTROMAGNETIC INTERFERENCE - Aspects of a method and system for adaptive tone cancellation for mitigating the effects of interference are provided. In this regard, an Ethernet PHY may receive one or more signals via a corresponding one or more physical channels and generate one or more estimate signals, each of which approximates interference present in a corresponding one of the received signals. The Ethernet PHY may subtract each one of the estimate signals from a corresponding one of the received signals. The subtracting may occur at the input of one or more slicers in the Ethernet PHY. The received signals may be processed via one or more equalizers in the Ethernet PHY. A decision output of a slicer in the Ethernet PHY may be subtracted from one of the said one or more received signals, and a signal resulting from the subtraction may be utilized to generate the one or more estimate signals.01-05-2012
20120207201Systems and Methods for Data Detection Using Distance Based Tuning - Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes an equalizer circuit and a data detection circuit. The equalizer circuit is operable to filter a series of samples based at least in part on a filter coefficient and to provide a corresponding series of filtered samples. The data detection circuit includes: a core data detector circuit and a coefficient determination circuit. The core data detector circuit is operable to perform a data detection process on the series of filtered samples and to provide a most likely path and a next most likely path. The coefficient determination circuit operable to update the filter coefficient based at least in part on the most likely path and the next most likely path.08-16-2012
20120027072Variable Modulus Mechanism for Performing Equalization Without A Priori Knowledge of Modulation Type or Constellation Order - A system, method and memory medium for performing blind equalization. A block {u02-02-2012
20090135896FAST AUTOMATIC GAIN CONTROL - An apparatus comprising a slicer configured to produce a symbol decision value and a symbol error value utilizing, at least in part, a slicer input signal; and an automatic gain controller configured to facilitate the automatic control of a gain applied to the slicer input signal by producing a gain control signal, the automatic gain controller comprising a decision-directed amplitude error detector configured to utilize, at least in part, the symbol decision value and the symbol error value to produce an amplitude error signal, and a loop filter configured to utilize the amplitude error signal to produce the gain control signal.05-28-2009
20100202505Equalizer Architecture for Data Communication - An update algorithm for equalizer coefficients in a communications system using phase correction symbols. Instead of using a traditional all symbols slicer update algorithm, the equalizer is updated during phase correction symbols for optimal performance in low signal-to-noise ratio conditions. In lower signal-to-noise ratio conditions, the equalizer uses a phase correction circuit to compensate for distortion caused by a communication channel when a demodulated data stream contains an unknown phase offsets resulting from a fast dynamic distortion. More specifically, the phase correction circuit uses a phase correction signal to correct for the unknown phase offsets in a demodulated data stream in lower signal-to-noise ratio conditions. The equalizer then corrects for distortion caused by the communication channel based upon the phase corrected demodulated data stream.08-12-2010
20120300829ADAPTIVELY SWITCHING EQUALIZATION OPERATIONS IN A NODE OF A WIRELESS NETWORK - At a node of a wireless network, equalization operations performed on signals received from a transmitter are adaptively switched to be equalized by an iterative turbo receiver or a linear receiver. A theoretical expression of a post-equalization SINR of a capacity-achieving receiver is used to estimate the post-equalization SINR performance of the turbo receiver. The estimated post-equalization SINR performance is then used as a basis to determine whether the received signal is to be equalized by the turbo receiver or the linear receiver.11-29-2012
20110007793JOINT TIME/FREQUENCY PROCESSING FOR WIRELESS RECEIVERS - Channel estimation and/or equalization processing is performed in a wireless receiver in two stages. The first stage involves pre-filtering in the frequency domain to compact a grid-based representation of the net channel. The second stage involves implementing reduced-complexity time domain channel estimation and/or equalization. According to one embodiment, a received signal transmitted over a net channel is processed by pre-filtering the received signal in the frequency domain. The frequency domain pre-filtering compacts an N-tap effective grid-based representation of the net channel into a K-tap compacted grid-based representation of the net channel where K01-13-2011
20110007792APPARATUS FOR CHANNEL ESTIMATION, APPARATUS FOR EQUALIZATION AND METHOD FOR EQUALIZATION - The present invention provides a channel estimation apparatus in which channel estimation may be made higher than heretofore in accuracy and may be used for calculating the weight for an equalization filter to achieve an optimum equalizing performance. A subcarrier copying unit 01-13-2011
20120155528ADAPTATION OF BASELINE WANDER CORRECTION LOOP GAIN SETTINGS - An apparatus including a first circuit and a second circuit. The first circuit may be configured to receive a signal, where low frequency content of the signal is attenuated due to high pass filtering by a medium carrying the signal and a coupling. The second circuit may be configured to automatically set a gain of a baseline wander correction loop to restore the low frequency content in the signal based upon a sample taken from a first point in a signal pathway of the first circuit.06-21-2012
20090245342EQUALIZER ADAPTING CIRCUIT - A channel equalizer having a filter arranged to filter an input signal, the filter including a plurality of taps, each tap generating an output signal based on a coefficient, an input for receiving the coefficients and an output for outputting a filtered signal; and coefficient generating circuitry including a graduation unit arranged to receive the input signal and an error signal indicating an error in the filtered signal, to accumulate gradient values relating to each of the coefficients based on a plurality of error values of the error signal, each of the gradient values indicating a required change in one of the coefficients, and to sequentially output the gradient values; and coefficient update unit arranged to sequentially update each of the filter coefficients in turn, based on the gradient values.10-01-2009
20110075719Radio Receiver Having a Multipath Equalizer - A radio receiver has a multipath equalizer that includes a filter and a coefficient estimator. The filter provides a reconstructed signal by applying a transfer function including a reflection coefficient and a delay coefficient to a multipath radio signal. The coefficient estimator adapts the reflection coefficient and the delay coefficient in response to a deviation in magnitude of the reconstructed signal from a normalized value. In one form, the filter evaluates the transfer function by truncating it to eight terms. In another form, the filter includes a delay line having delay elements for storing samples of the multipath radio signal received both before and after a current sample. In yet another form, the multipath equalizer further includes a normalizer that receives the multipath radio signal and provides a normalized multipath radio signal having a normalized magnitude to an input of the filter.03-31-2011
20100172400ADAPTIVE EQUALIZATION APPARATUS WITH EQUALIZATION PARAMETER SETTING ADPATIVELY ADJUSTED ACCORDING TO EDGES OF EQUALIZER OUTPUT MONITORED IN REAL-TIME MANNER AND RELATED METHOD THEREOF - An adaptive equalization apparatus is provided. The adaptive equalization apparatus includes an equalizer, a monitor circuit, and a control circuit. The equalizer receives a first signal, and equalizes the first signal according to an equalization parameter setting to thereby generate a second signal. The monitor circuit is electrically connected to the equalizer, and monitors edges of the second signal in a real-time manner to thereby generate a detection result. The control logic is electrically connected to the equalizer, and adaptively adjusts the equalization parameter setting according to the detection result.07-08-2010
20110103455ADAPTIVE DIGITAL POST DISTORTION REDUCTION - A method for adaptive digital post distortion reduction is described. An analog radio frequency (RF) signal is received. The frequency of the analog RF signal is downconverted using analog circuitry. The analog RF signal is converted to a digital signal using an analog to digital converter (ADC). Digital post distortion reduction is applied to the digital signal to reduce nonlinearities in the digital signal.05-05-2011
20110103454COGNITIVE RADIO DEVICE - An example Cognitive Radio (CR) described herein may include equalization and Automatic Modulation Classification (AMC). The equalization may employ digital filter techniques with an adjustable length or order. The output of the equalization may be provided to the AMC, where the AMC may be adapted to identify various characteristics about the RF environment and also to identify probabilities of classification associated with the performance of the AMC itself. The CR device may be configured to adjust the equalization using feedback from the AMC to enhance performance of each other.05-05-2011
20110103457METHOD OF DYNAMIC CONTROL OF THE FOCUSING OF A SIGNAL PRE-EQUALIZED BY TIME REVERSAL - A method is provided for dynamically controlling the focus of a signal pre-equalized by time reversal of an estimated propagation channel between a source antenna of a source communicating entity and a destination antenna of a destination communicating entity at a current instant, said method comprising steps for evaluation by the destination communicating entity of a relative focus quality of the pre-equalized signal sent by the source antenna and received by the destination antenna, compared to a quality at a focal point, and if the evaluated relative focus quality does not satisfy a predetermined criterion, for request, by the destination communicating entity, to modify the focus addressed to the source communicating entity for a subsequent instant.05-05-2011
20120314755ADAPTIVE EQUALIZER WITH A DUAL-MODE ACTIVE TAPS MASK GENERATOR AND A PILOT REFERENCE SIGNAL AMPLITUDE CONTROL UNIT - An adaptive equalizer including an equalizer filter and a tap coefficients generator used to process a sample data stream derived from a plurality of received signals is disclosed. The tap coefficients generator includes an equalizer tap update unit, a vector norm square estimator, an active taps mask generator, a switch and a pilot amplitude reference unit used to minimize the dynamic range of the equalizer filter. A dynamic mask vector is used to mask active taps generated by the equalizer tap update unit when an unmasked signal output by the equalizer filter is selected by the switch to generate an error signal fed to the equalizer tap update unit. A fixed mask vector is used to mask active taps generated by the equalizer tap update unit when a masked signal output by the equalizer filter is used to generate the error signal.12-13-2012
20120314754METHOD AND SYSTEM FOR OFDM FRAME BOUNDARY DETECTION IN A VEHICULAR MULTIPATH CHANNEL - Embodiments of a method for OFDM frame boundary detection in a vehicular multipath channel include use of a maximal channel energy instead of a strongest path for detecting a frame boundary. A sample of OFDM data inputs is processed using long preamble local copy correlation and integration to obtain a channel energy which sums all paths of the multipath. A plurality of such channel energies obtained within a given time period are searched for a maximal channel energy, which, when found, is used to detect the frame boundary.12-13-2012
20120170638ADAPTIVE EQUALIZER AND ADAPTIVE EQUALIZING METHOD - An adaptive equalizer adapted to compensate a signal transmitted by a channel is provided. The adaptive equalizer includes a signal booster, an amplifier unit and an adaptive control loop. The signal booster receives the signal, adjusts gain for the signal, and outputs the signal which has been adjusted. The amplifier unit is coupled to the signal booster, amplifies the signal and outputs it to the next stage. The adaptive control loop is coupled to the signal booster, detects a ratio of a maximum value and a minimum value of the signal package, and outputs an adjusting signal to adjust the gain of the signal booster to change the maximum value or the minimum value, so that the ratio of the maximum value and the minimum value is not less than a specific value. Furthermore, an adaptive equalizing method is also provided.07-05-2012
20120121004DIFFERENTIAL EQUALIZERS WITH SOURCE DEGENERATION AND FEEDBACK CIRCUITS - An embodiment of an equalizer includes a voltage-to-current converter and a current-to-voltage converter. The voltage-to-current converter is configured to convert a differential input voltage to a differential current, and includes a differential amplifier with a first transistor and a second transistor, and a first source degeneration circuit coupled between the first transistor and the second transistor. An embodiment of the first source degeneration circuit includes a first resonant circuit. The current-to-voltage converter is coupled to the voltage-to-current converter, and is configured to convert the differential current to a differential output voltage. The current-to-voltage converter includes a first inverter with a first feedback circuit and a second inverter coupled to the first inverter, which includes a second feedback circuit. An embodiment of the first feedback circuit includes a second resonant circuit, and an embodiment of the second feedback circuit includes a third resonant circuit.05-17-2012
20120121006Equalizer Architecture for Data Communication - An update algorithm for equalizer coefficients in a communications system using phase correction symbols. Instead of using a traditional all symbols slicer update algorithm, the equalizer is updated during phase correction symbols for optimal performance in low signal-to-noise ratio conditions. In lower signal-to-noise ratio conditions, the equalizer uses a phase correction circuit to compensate for distortion caused by a communication channel when a demodulated data stream contains an unknown phase offsets resulting from a fast dynamic distortion. More specifically, the phase correction circuit uses a phase correction signal to correct for the unknown phase offsets in a demodulated data stream in lower signal-to-noise ratio conditions. The equalizer then corrects for distortion caused by the communication channel based upon the phase corrected demodulated data stream.05-17-2012
20120121005CONCATENATION-ASSISTED SYMBOL-LEVEL COMBINING FOR MIMO SYSTEMS WITH HARQ AND/OR REPETITION CODING - Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors from the same transmitted vector. The receiver combines the received vectors by vector concatenation The concatenated vector may then be decoded using, for example, maximum-likelihood decoding. In some embodiments, the combined signal vector is equalized before decoding.05-17-2012
20110116536NARROW-BAND INTERFERENCE DETECTOR, SIGNAL RECEIVER EMPLOYING NARROW-BAND INTERFERENCE DETECTOR AND CONTROLLING DEMODULATOR PARAMETER SETTING ACCORDING TO NARROW-BAND INTERFERENCE DETECTION RESULT, AND RELATED METHODS THEREOF - A signal receiver includes a demodulator, a narrow-band interference detector, and a control module, where the demodulator is for performing signal demodulation upon a received communication signal, the narrow-band interference detector is for performing narrow-band interference detection and accordingly generating a detection result, and the control module is for controlling an operation of the demodulator according to the detection result. In addition, a narrow-band interference detector includes an input port and a processing circuit, where the input port is coupled to an equalizer included in a signal receiver for receiving a signal generated from the equalizer, and the processing circuit is coupled to the input port for performing a narrow-band interference detection according to the signal generated from the equalizer, and accordingly generating a detection result.05-19-2011
20100246658SYSTEM AND METHOD FOR PROGRAMMABLY ADJUSTING GAIN AND FREQUENCY RESPONSE IN A 10-GIGABIT ETHERNET/FIBRE CHANNEL SYSTEM - Systems and methods for optimizing operation of a transceiver device are disclosed. The method may include parallel processing an input signal through a first path having a first frequency response and a second path having a second frequency response. The second frequency response may be higher than the first frequency response. Signals from the first and second paths may be combined, creating an output signal having a desired gain and frequency. The parallel processing may adjust a gain of at least one of the first path and the second path. The parallel processing may equalize at least one of the first frequency response and the second frequency response. The input signal may be from a 10 GBit Ethernet channel and/or a Fibre channel.09-30-2010
20100246657Apparatus and Methods for Digital Adaptive Equalizer in Serial Receiver - Circuits and methods for performing adaptive frequency compensation in a serial receiver coupled to a differential signal channel link are disclosed. In an exemplary embodiment, a receiver for signals over a serial channel link is provided including a linear equalization function. A data recovery circuit is coupled to the output of the receiver and receives frequency compensated analog signals. A digital feedback control circuit observes the digital output. A data accumulator circuit receives the output of a comparator and a signal indicating the data pattern observed in the digital data output. A digital filter receives the accumulator data and outputs control signals for modifying the linear equalization in a feedback loop. The receiver and linear equalization function are automatically and adaptively modified to provide frequency compensation. Methods for adaptively modifying the frequency response of a receiver and linear equalizer using digital feedback are disclosed.09-30-2010
20120163443Adaptive Known Signal Canceller - An adaptive known signal canceller comprising of a known signal canceller filter responsive to a known signal including a known portion of a transmitted signal, the known signal canceller filter operative to generate a filtered known signal, and a subtractor unit responsive to an input signal and operative to generate an output signal, the subtractor unit configured to subtract the filtered known signal from the input signal to generate an output signal, such that the known portion of the transmitted signal is substantially removed from the input signal. The adaptive known signal canceller further comprising of a known signal canceller update unit, responsive to a desired signal and an output signal and operative to continually adjust the coefficients of the known signal canceller filter based on the difference between the output signal and the desired signal, so that the filter coefficients substantially reflect the impulse response of a channel.06-28-2012
20120128054SINGLE PATH DETECTION AND EQUALIZER OPTIMIZATION - An algorithm to detect single path channel conditions and reduce the span (number of taps) of the equalizer in order to mitigate the performance degradation caused by noisy equalizer taps is disclosed. The algorithm provides two novel components comprising single path scenario detection and single path scenario processing or (equalizer shortening). A single path scenario is detected when the energy concentrated in a single channel impulse response tap divided by the total energy of the taps exceeds a predetermined threshold. When a single path scenario is detected, only the equalizer taps within a variable window around the equalizer tap having concentrated energy are used to filter the received signal.05-24-2012
20120128053METHOD AND APPARATUS FOR CONTROLLING A CONTINUOUS TIME LINEAR EQUALIZER - An example method for controlling a continuous time linear equalizer includes: developing a voltage histogram of a signal present at an output of a continuous time linear equalizer; developing a quality factor for the voltage histogram; comparing the quality factor with a prior quality factor; decreasing an equalization of the continuous time linear equalizer if the quality factor is less than the prior quality factor and increasing the equalization of the continuous time linear equalizer if the quality factor is greater than the prior quality factor.05-24-2012
20120213267PARTIAL RESPONSE RECEIVER - A signaling system is described. The signaling system comprises a transmit device, a receive device including a partial response receive circuit, and a signaling path coupling the transmit device and the receive device. The receive device observes an equalized signal from the signaling path, and includes circuitry to use feedback from the most recent previously resolved symbol to sample a currently incoming symbol. The transmit device equalizes transmit data to transmit the equalized signal, by applying weighting based on one or more data values not associated with the most recent previously resolved symbol value.08-23-2012
20110182347ADAPTIVE EQUALIZER AND ADAPTIVE EQUALIZING METHOD - An adaptive equalizer includes an equalization circuit and an operation number change unit. The equalization circuit includes a plurality of cascade-coupled delay taps. The equalization circuit equalizes an input signal by adding calculation results of the plurality of delay taps. The operation number change unit changes a number of operations of the plurality of delay taps according to an equalization error of the equalization circuit.07-28-2011
20090060020METHOD AND APPARATUS FOR ESTIMATING AND CORRECTING BASEBAND FREQUENCY ERROR IN A RECEIVER - A method and apparatus for estimating and correcting baseband frequency error in a receiver. In one embodiment, an equalizer performs equalization on a sample data stream and generates filter tap values based on the equalization. An estimated frequency error signal is generated based on at least one of the filter tap values. A rotating phasor is generated based on the estimated frequency error signal. The rotating phasor signal is multiplied with the sample data stream to correct the frequency of the sample data stream. In another embodiment, a channel estimator performs channel estimation and generates Rake receiver finger weights based on at least one of the finger weights. An estimated frequency error signal is generated based on at least one of the finger weights.03-05-2009
20120257669DATA PROCESSING METHOD, EQUALIZER AND RECEIVER - A data processing method, an equalizer, and a receiver in a wireless communication system including a relay station are provided. The data processing method includes: receiving a base station signal from a base station; receiving a relay station signal from a relay station; determining a propagation delay between the base station signal and the relay station signal; generating an equalizing signal in which interference generated between the base station signal and the relay station signal is alleviated in consideration of the propagation delay; and recovering information bits transmitted by the base station from the equalizing signal. According to an exemplary embodiment of the present invention, it is possible to alleviate performance deterioration due to an interference problem generated in a relay system.10-11-2012
20120076194RECEIVER EMPLOYING NON-PILOT REFERENCE CHANNELS FOR EQUALIZING A RECEIVED SIGNAL - In one embodiment, a receiver has a reference generator and a main equalizer. The reference generator equalizes a received signal using one or more pilot reference signals. Then, the reference generator decodes one or more predetermined data channels of the equalized signal, makes hard decisions on the data of each decoded channel, and regenerates the original coding sequence of each decoded channel. The main equalizer uses each re-encoded channel as an additional reference signal along with one or more pilot signals to equalize a time-delayed version of the received signal. In alternative embodiments, the receiver might also have a step-size generator which selects optimum step sizes from a look-up table based on the number of re-encoded channels and the power of those channels. The step size is then used by the main equalizer along with the re-encoded channels to equalize the time-delayed received signal.03-29-2012
20120076193System and Method for Linear Distortion Estimation By Way of Equalizer Coefficients - Provided is a method and system for estimating distortion in a communications channel including an adaptive equalizer. The method includes determining one or more adaptive filter coefficients associated with a signal passed through the equalizer. The method also includes estimating un-equalized channel distortion based upon the determined adaptive filter coefficients.03-29-2012
20110103456METHOD AND SYSTEM FOR LOW COMPLEXITY CONJUGATE GRADIENT BASED EQUALIZATION IN A WIRELESS SYSTEM - A method for processing signals includes, in a wireless system comprising one or more processors and/or circuits integrated within a single chip, initializing values related to at least one channel response vector and at least one correlation vector using a conjugate gradient-based (CG) algorithm. A plurality of filter taps may be updated utilizing at least one channel response vector and at least one correlation vector, for a plurality of received clusters, based on the initialized values and at least one signal-to-noise ratio (SNR) for the received signal clusters. At least a portion of the received signal clusters may be filtered utilizing at least a portion of the updated plurality of filter taps. The updating may be repeated whenever a specified signal-to-noise ratio (SNR) for the received clusters is reached. The initialized values may be updated during a plurality of iterations.05-05-2011
20120177098RECEIVER CIRCUIT - A first phase adjustment circuit adjusts phases of a data decision clock signal and a first boundary decision clock signal according to a phase adjustment amount based on an output signal of a data decision circuit and an output signal of a first boundary decision circuit. A second phase adjustment circuit adjusts a phase of a second boundary decision clock signal according to a result of adding the phase adjustment amount and a phase adjustment amount offset. An adaptive equalization control circuit adjusts an equalization coefficient of an equalization circuit according to a data width of an output signal of the equalization circuit based on a logical comparison result between the output signal of the data decision circuit and an output signal of a second boundary decision circuit when the phase adjustment amount offset is changed.07-12-2012
20100272168 RECEIVER - A receiver for a telecommunications system in which a data signal is transmitted using a closed loop transmit diversity system and a pilot signal is transmitted using a space time transmit diversity system, the receiver comprising an equalizer for equalising a signal received by the receiver, wherein the equalizer is configured to produce an equalized signal in which effects caused by a propagation channel through which the data signal was transmitted are alleviated, the receiver further comprising a processor for processing the equalized received signal to recover the pilot signal.10-28-2010
20100008412CONTROL APPARATUS FOR AND CONTROL METHOD OF EQUALIZER, AND WIRELESS TERMINAL HAVNG THAT CONTROL APPARATUS - For the first wireless base station, a first correlation value based on a calculation result on channel estimation values having an identical signal timing and a calculation result on channel estimation values having different signal timings, and determines, for the second wireless base station, a second correlation value based on a calculation result on channel estimation values having an identical signal timing, and controls the weighting-adding at the equalizer based on these correlation values.01-14-2010
20100266006SIGNALING SYSTEM WITH SELECTIVELY-INHIBITED ADAPTIVE EQUALIZATION - An integrated circuit having a receiver that selectively inhibits incoming data from being used to update adaptively generated controls. Sampling circuitry generates a plurality of samples of an incoming signal. Control circuitry generates an inhibit signal in either a first state or a second state according to whether the plurality of samples meets a randomness criterion. Tap weight update circuitry receives the inhibit signal from the control circuitry and updates a plurality of equalizer tap weights based on the plurality of samples if the inhibit signal is in the first state. The tap weight update circuitry refrains from updating the plurality of equalizer tap weights based on the plurality of samples if the inhibit signal is in the second state.10-21-2010
20120189046Asymmetric Multi-Channel Adaptive Equalizer - An apparatus is disclosed to compensate for non-linear effects resulting from the transmitter, the receiver, and/or the communication channel in a communication system. A receiver of the communication system contains an image cancellation module that compensates for images generated during the modulation and/or demodulation process. The image cancellation module includes a fine carrier correction loop to correct for frequency offsets between the transmitter and receiver. The image cancellation module includes a coarse acquisition mode and a decision directed mode. The decision directed mode allows for a larger signal-to-noise ratio for the receiver when compared against the coarse acquisition mode.07-26-2012
20090185613High-Speed Receiver Architecture - A receiver (e.g., for a 10 G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decoder, for example a sliding block Viterbi decoder (SBVD); and the FFE and/or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.07-23-2009
20090022217EQUALIZER AND EQUALIZATION METHOD - A correction coefficient calculating section 01-22-2009
20120082202Methods and Systems for Combined Cyclic Delay Diversity and Precoding of Radio Signals - In a transmitter or transceiver, signals can be precoded by multiplying symbol vectors with various matrices. For example, symbol vectors can be multiplied with a first column subset of unitary matrix which spreads symbols in the symbol vectors across virtual transmit antennas, a second diagonal matrix which changes a phase of the virtual transmit antennas, and a third precoding matrix which distributes the transmission across the transmit antennas.04-05-2012
20120263223LINEAR EQUALIZER - A linear equalizer (LEQ) includes a first transconductance device coupled to an input node of the LEQ and a second transconductance device AC coupled to the input node of the LEQ to increase a gain of the LEQ for data signals above a predetermined frequency. The first transconductance device and the second transconductance device are of complimentary types. A bimodal LEQ includes inputs to control operation of the bimodal LEQ in a current mode or a voltage mode. The bimodal LEQ includes first and second transconductance devices. One of the first and second transconductance devices is AC coupled to an input node to increase the gain for data signals above a predetermined frequency.10-18-2012
20120263222Maximum-Likelihood MIMO Demodulation for Frequency-Selective Channels - A method is described that enables maximum-likelihood (ML) demodulation for MIMO communications over frequency-selective channels. An equalizer is typically employed to suppress inter-symbol interference (ISI) due to frequency-selectiveness of the channel, but the noise of the equalizer output can be highly correlated such that standard ML-MIMO demodulations cannot directly apply. The method comprises first constructing equivalent post-equalization MIMO channel and noise covariance matrix, and then de-correlating the equalizer output so that ML or near-ML MIMO demodulations can be applied to improve the performance. Additionally, successive ISI cancellation (SIC) is described for further performance improvement.10-18-2012
20090016421PARAMETER CONTROL CIRCUIT - An interface circuit inputting and outputting data and a clock that have multiple speeds is provided with an equalizer capable of changing a circuit parameter, a frequency detection part detecting a clock frequency, and a parameter calculation control part calculating an appropriate circuit parameter according to the clock frequency and controlling the equalizer. The frequency detection part detects at what frequency the interface circuit is operating presently and sends the frequency to the parameter calculation control part. The parameter calculation control part calculates the circuit parameter of the equalizer so that the interface circuit operates optimally at the detected frequency, and sets the circuit parameter to the equalizer. In this manner, since the circuit parameter of the equalizer in the interface circuit can be controlled appropriately according to the frequency of the input and output clock, optimum operation is always available.01-15-2009
20120327993Adaptive Equalization Using Correlation Of Edge Samples With Data Patterns - An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.12-27-2012
20120230383Linear distortion and interference estimation using decision feedback equalizer coefficients - Linear distortion and interference estimation using decision feedback equalizer coefficients. Processing of different respective groups of equalizer coefficients may be made to determine the residual frequency response of an equalizer and/or device in which the equalizer is implemented. Such an equalizer may be in woman within any of a number of respective communication devices including those operative within satellite, wireless, wired, fiber-optic, and/or mobile communication systems. A first group of equalizer coefficients corresponds to certain filtering characteristics of the equalizer and/or device in which the equalizer is implemented. The equalizer is implemented to process a signal to generate a second group of equalizer coefficients. Processing and/or analysis of the first group of equalizer coefficients and the second group of equalizer coefficients will generate a third group of equalizer coefficients corresponding to the residual frequency response of the equalizer and/or device in which the equalizer is implemented.09-13-2012
20120269253METHOD FOR PROCESSING SIGNALS - A method for processing signals transmitted via a connection and received by a digital interface, where individual data frames are transmitted by the signals as a sequence of modulated symbols, and where the received signals are corrected by an equalizer; the equalizer sampling the received signals, and an adaptation of the equalizer only taking place in particular time intervals in a manner controlled by a protocol.10-25-2012
20100232493RADIO TRANSMITTER IQ IMBALANCE MEASUREMENT AND CORRECTION METHODS AND APPARATUS - Embodiments include transceivers and transmit IQ imbalance correction methods. A transmitter lineup, which includes an equalizer and an RF modulator, receives a stream of baseband samples having real and imaginary components, processes the real components along a first channel, and processes the imaginary components along a second channel to produce processed real and imaginary components. The equalizer equalizes at least one of the processed real components and the processed imaginary components to compensate for offset frequency-dependent components of transmitter IQ imbalance. The RF modulator receives and modulates analog versions of the equalized samples, resulting in an analog RF signal. An embodiment also includes a balancer adapted to apply IQ gain and phase correction to the equalized samples to compensate for offset frequency-independent components of the transmitter IQ imbalance. A calibration processing subsystem determines filter coefficients used by the equalizer and IQ gain and phase correction values used by the balancer.09-16-2010
20100232492Transmitter control in communication systems - Techniques are described to adaptively adjust the equalizer settings of each transmitter in a transmitter-receiver pair. The transmitter-receiver pair can be used at least with implementations that comply with 40GBASE-CR4 or 100GBASE-CR10. For implementations that comply with 40GBASE-CR4, equalizer settings of four transmitters may be independently established.09-16-2010
20120087406DEVICE AND METHOD FOR RECEIVING DOWNLINK SIGNAL IN WIRELESS COMMUNICATION SYSTEM - A device and method is provided for iterative inter-cell interference cancellation and channel equalization in the mobile communication system. A downlink receiver of a mobile communication system according to the present invention includes a channel estimator for estimating channel impulse response of a selected cell from channel signals of respective cells; an equalizer for equalizing the channel impulse response output by the channel estimator using an equalization coefficient; a despreader for generating a symbol observation value per code channel by despreading the output of the equalizer with a code of the selected cell; and a cell interference estimator for estimating a symbol signal power and noise power of a data code channel from the symbol observation value and generates the estimated MMSE as a chip level regeneration sample.04-12-2012
20120087405Trace Canceller with Equalizer Adjusted for Trace Length Driving Variable-Gain Amplifier with Automatic Gain Control Loop - Distortions of both amplitude and phase along a transmission line are compensated for by a trace canceller inserted between a transmitter and a receiver. The trace canceller has an equalizer that compensates for a trace length between the transmitter and the trace canceller. A variable gain amplifier between the equalizer and an output buffer has its gain controlled by an automatic gain control circuit that compares low-frequency swings of the input and output of the trace canceller. The gain of the variable gain amplifier is reduced to prevent the output buffer from saturating and clipping peak voltages on its output. Thus both the variable gain amplifier and the output buffer remain in the linear region. Training pulses from the transmitter are passed through the trace canceller without clipping of peak voltages, allowing the transmitter and receiver to adjust transmission parameters to best match the transmission line.04-12-2012
20120320963EQUALIZATION USING SERIAL LOCALIZATION WITH INDECISION - A receiver includes a constellation processing module and a plurality of equalization stages. The constellation processing module groups points of a constellation associated with a transmitted signal into a plurality of subsets. At least two adjacent ones of the subsets have one or more common constellation points so that the at least two adjacent subsets overlap. The constellation processing module also determines a centroid-based value for each of the subsets of constellation points and groups the centroid-based values into one or more sets. Each of the equalization stages except for a the last equalization stage localizes a search for a final symbol decision using the set of centroid-based values input to or selected by the equalization stage as constellation points. The last equalization stage determines the final symbol decision using the subset of constellation points input to or selected by the last equalization stage.12-20-2012
20100220779COMMON BROADCAST RECEIVER AND METHOD FOR PROCESSING A RECEIVED SIGNAL THEREOF - A common broadcast receiver that receives cable broadcast, terrestrial broadcast, and mobile broadcast signals is provided. The common broadcast receiver includes a synchronizer for receiving any one of a cable broadcast signal, a terrestrial broadcast signal, and a mobile broadcast signal including a training signal generated by a Deterministic Trellis Reset (DTR) and inserted in a data region, and synchronizing the received broadcast signal; and a signal detector for detecting any one of the cable broadcast signal, the terrestrial broadcast signal, and the mobile broadcast signal from the synchronized broadcast signal. Hence, the mobile broadcast signal can be received and processed in addition to the cable broadcast signal and the terrestrial broadcast signal.09-02-2010
20130010855Multiphase receiver with equalization circuitry - An integrated circuit device includes a first circuit to receive bits associated with a first data cycle of an electrical input signal, operable to produce a decision regarding logic state of the bits associated with the first data cycle, and a second circuit to receive bits associated with a second cycle of the electrical input signal, to produce a decision regarding logic state of the bits associated with the second data cycle. An equalizing circuit compensates for intersymbol interference affecting the second circuit dependent on an output of the first circuit and compensates for intersymbol interference affecting the first circuit dependent on an output of a circuit other than the first circuit operable to produce a decision regarding logic state of bits of the electrical input signal.01-10-2013
20130016767METHOD AND APPARATUS FOR DETERMINING CHANNEL STATE INFORMATIONAANM Pean; JohanAACI DresdenAACO DEAAGP Pean; Johan Dresden DEAANM Bury; AndreasAACI DresdenAACO DEAAGP Bury; Andreas Dresden DE - A mobile station receiving a signal from a base station experiences time/frequency varying channel conditions. In order to get the maximum throughput from a base-station, it is necessary to adjust the modulation and coding schemes to the actual channel quality. To do so, mobile receivers are required to probe the radio channel condition and feedback a limited set of estimated channel state information parameters such as CQI, RI, and PMI. The invention uses modulation-specific mutual information as a basic metric for CQI-PMI-RI computation to yield high bandwidth efficiency under both flat fading and interference conditions as well as time and frequency selective fading and interference conditions, at reasonable complexity.01-17-2013
20100124267APPARATUS AND METHOD FOR DETECTING INTERFERENCE WAVE - An interference wave detecting apparatus includes a first Fourier transformer for frequency-converting a received signal using Fourier transform; an extractor for extracting a known information signal from the frequency-converted received signal; an interpolator for performing interpolation to the known information signal in frequency domain, thereby generating a first transmission path estimation signal as a frequency-domain information signal; an inverse Fourier transformer for inverse-Fourier-transforming the known information signal, thereby generating a time-domain information signal; a waveform shaping section for shaping a waveform of the time-domain information signal; a second Fourier transformer for Fourier-transforming the shaped time-domain information signal, thereby generating a second transmission path estimation signal as a frequency-domain information signal; and a comparing-computing section for comparing the first and second transmission path estimation signals, thereby generating an interference wave detection result which indicates a ratio of an interference wave of the received signal.05-20-2010
20130022098ADAPTIVE EQUALIZER AND OPERATING METHOD THEREOF - An adaptive equalizer and operating method thereof are disclosed. The adaptive equalizer is oversampling-based. The adaptive equalizer includes a searching module, a compensation module, and an operating module. The searching module searches the equalizer setting from a lower compensation to a higher compensation to obtain a first equalizer setup value according a first monitored result of a monitor and then searches the equalizer setting from a higher compensation to a lower compensation to obtain a second equalizer setup value according to a second monitored result of the monitor. The operating module performs an operation on the first equalizer setup value and the second equalizer setup value to obtain an optimized equalizer setup value.01-24-2013
20130022097ADAPTIVE FREQUENCY-DOMAIN EQUALIZATION FOR WIRELESS RECEIVERS - According to various embodiments, devices and methods disclosed herein include performing, using a processor, a linear operation on a first plurality of channel frequency responses and a plurality of corresponding predictor coefficients to estimate a new channel frequency response. Each of the plurality of corresponding predictor coefficients may be updated based on an error value and a second plurality of channel frequency responses to obtain an updated predictor coefficient. The error value may be computed based on an estimated current channel frequency response and a predicted current channel frequency response. The new channel frequency response may be used to equalize a received modulated signal including a single-carrier modulated signal, e.g., a signal modulated using a vestigial sideband modulation scheme, or a quadrature amplitude modulation scheme.01-24-2013
20130170539COMMUNICATION DEVICE CAPABLE OF CHANNEL ESTIMATION AND METHOD THEREOF - Communication methods and communication devices are disclosed. The communication method, performed by a communication device, including: receiving a time-domain OFDM symbol; converting the time-domain OFDM symbol to a frequency-domain OFDM symbol containing a plurality of pilot sub-carrier received signals; extracting the plurality of pilot sub-carrier received signals from the frequency-domain OFDM symbol; estimating a plurality of first frequency-domain channel average responses (CARs) of pilot sub-carriers according to the plurality of pilot sub-carrier received signals and a plurality of pilot sub-carrier transmitted signals; determining a pilot sub-carrier number parameter for a sub-carrier block according to a statistical information of channel delay; splitting all sub-carriers into a plurality of sub-carrier blocks according to the pilot sub-carrier number parameter; and estimating second frequency-domain CARs of all sub-carriers by performing weighting average and interpolation based on the first frequency-domain CARs of the pilot sub-carriers in all sub-carrier blocks.07-04-2013
20080232453Combining least squares and least mean squares algorithms to determine equalizer tap values - A method of operating an equalizer includes combining a Least Mean Squares (LMS) algorithm and a Least Squares (LS) algorithm to determine a set of equalizer tap values to be used in processing a signal. A channel impulse response (CIR) is computed, and an equalizer taps interval is then determined based on the CIR. The LS algorithm is used to determine a set of equalizer major taps based on the interval, and the LMS algorithm is used to determine a set of equalizer minor taps based on the interval.09-25-2008
20080225937METHOD AND SYSTEM OF PROVIDING A HIGH SPEED TOMLINSON-HARASHIMA PRECODER - Herein described are at least a method and a system for implementing a high speed Tomlinson-Harashima Precoder. The method comprises using an L-tap transpose configuration of a Tomlinson-Harashima Precoder and processing a first discrete time sampled sequence using said L coefficients and L state variables by clocking the L-tap Tomlinson-Harashima Precoder using a clock signal wherein the clock signal has a clock rate equal to one half the symbol rate of the discrete time sampled sequence. In a representative embodiment, an L-tap Tomlinson-Harashima Precoder comprises a single integrated circuit chip, wherein the integrated circuit chip comprises at least one circuitry for processing a discrete time sampled sequence using L coefficients and L state variables by way of clocking the discrete time sampled sequence using a clock signal having a clock rate that is one half the symbol rate of the discrete time sampled sequence.09-18-2008
20130142244ADAPTIVE EQUALIZER - An adaptive equalizer circuit, set forth by way of example and not limitation, includes a plurality of paths receiving an input signal. One or more equalizers are each provided on one of the paths and are operative to equalize signal amplitude. An equalizer selector receives the input signal and is operative to output a selection signal based on higher-frequency content and lower-frequency content of the input signal. The selection signal is operative to select one of the paths to output an output signal that is based on the input signal.06-06-2013
20090052514METHOD AND APPARATUS FOR GENERATING COEFFICIENTS IN A MULTI-INPUT-MULTI-OUTPUT (MIMO) SYSTEM - SIC equalizer coefficients for multiple layers are concurrently generated in a manner that reduces computational overhead and complexity. If number of transmit antennas (M02-26-2009
20130177064RECEPTION DEVICE AND METHOD - In a reception device and a reception method for a multivalue VSB, QPSK, or mutlivalue QAM modulated signal, reliability information (R) is generated (07-11-2013
20130114664METHOD AND APPARATUS FOR PERFORMING CHANNEL SHORTENING EQUALIZATION WITH FREQUENCY NOTCH MITIGATION - A method for performing channel shortening equalization with frequency notch mitigation is provided, where the method is applied to an electronic device. The method includes: obtaining channel response information from channel estimation to determine a relaxed channel convolution matrix corresponding to the channel response information, with the relaxed channel convolution matrix being a partial matrix of a channel convolution matrix corresponding to the channel response information, wherein the relaxed channel convolution matrix is obtained from omitting a portion of matrix elements of the channel convolution matrix; and based upon the relaxed channel convolution matrix, jointly performing time domain channel shortening control and frequency domain flatness control over the TEQ to perform channel shortening equalization with frequency notch mitigation by utilizing the TEQ. In particular, the portion of matrix elements includes a plurality of rows of matrix elements within the channel convolution matrix. An associated apparatus is also provided.05-09-2013
20130101009DATA STREAM PROCESSING METHOD, DEVICE, AND SYSTEM - The present invention provides a data stream processing method, device, and system. The data stream processing method includes: using a precoding parameter to perform precoding processing on an l04-25-2013
20130121395FOLDING SEQUENTIAL ADAPTIVE EQUALIZER - A folding adaptive equalizer is provided. The equalizer comprises an equalizer core and an automatic gain control loop. The equalizing transfer function of the equalizer core is modulated by one or more gain control signals generated by the automatic gain control loop and by a folding signal generated by the automatic gain control loop. When the folding signal is inactive, an increase in the gain control signals produces an increase in the high-frequency, high-bandwidth gain of the transfer function of the equalizer core. When the folding signal is active, further gain can be applied by decreasing the gain control signals, which produces a frequency-shift in the transfer function of the equalizer core toward lower bandwidth and an increase in the high-frequency, low-bandwidth gain of the transfer function of the equalizer core.05-16-2013
20130121394COMMUNICATION TERMINALS AND METHODS FOR CONTROLLING A RECEIVER OF A COMMUNICATION TERMINAL - A communication terminal is described comprising a determiner configured to determine, for at least one communication connection of the communication terminal, a type of the physical channel used by the communication connection and a type of data transmitted via the communication connection and a controller configured to control a receiver of the communication terminal to use a reception performance enhancement functionality depending on the type of the physical channel and the type of data transmitted via the communication connection.05-16-2013
20130128944Selectable-tap Equalizer - A signaling circuit having a selectable-tap equalizer. The signaling circuit includes a buffer, a select circuit and an equalizing circuit. The buffer is used to store a plurality of data values that correspond to data signals transmitted on a signaling path during a first time interval. The select circuit is coupled to the buffer to select a subset of data values from the plurality of data values according to a select value. The equalizing circuit is coupled to receive the subset of data values from the select circuit and is adapted to adjust, according to the subset of data values, a signal level that corresponds to a data signal transmitted on the signaling path during a second time interval.05-23-2013
20130128945Method and System for Low Complexity Conjugate Gradient Based Equalization in a Wireless System - Methods and systems for processing signals in a receiver are disclosed herein and may include updating a plurality of filter taps utilizing at least one channel response vector and at least one correlation vector, for a plurality of received clusters, based on initialized values related to the at least one channel response vector and the at least one correlation vector. At least a portion of the received signal clusters may be filtered utilizing at least a portion of the updated plurality of filter taps. The update may be repeated whenever a specified signal-to-noise ratio (SNR) for the received signal clusters is reached. The initialized values may be updated during a plurality of iterations, and the update may be repeated whenever a specified number of the plurality of iterations is reached.05-23-2013
20130128943APPARATUS AND METHOD THEREOF FOR COMPENSATING FOR GAIN CHANGES OF N-PAM MODULATE SIGNALS - A method for compensating for gain changes of an N-level pulse amplitude modulation (PAM-N) modulated signal. The method comprises comparing the PAM-N modulated signal to N−1 configurable thresholds, wherein the input PAM-N modulated signal is also equalized and the N−1 configurable thresholds are N−1 different voltage levels; tracking gain changes in the input PAM-N modulated signal by comparing the input PAM-N modulated signal to a compensation threshold; and adjusting a level of the at least one of the N−1 configurable thresholds of the N−1 comparators based on an output of the compensation comparator, thereby offsetting a crossing point of the at least one comparator respective of the at least one of the N−1 configurable thresholds to compensate for gain changes in the input PAM-N modulated signal.05-23-2013
20080198914Architecture for Systolic Nonlinear Filter Processors - Described are nonlinear filter processors having an array of polynomial nonlinear filters including a first polynomial nonlinear filter and a last polynomial nonlinear filter. The first polynomial nonlinear filter has an input terminal for receiving an input data sample. The polynomial nonlinear filters systolically pass the input data sample from the first polynomial nonlinear filter to the last polynomial nonlinear filter. Each polynomial nonlinear filter produces an output data sample based on the input data sample. In addition, each polynomial nonlinear filter other than the last polynomial nonlinear filter systolically passes the output data sample generated by that polynomial nonlinear filter to a neighboring polynomial nonlinear filter. Each polynomial nonlinear filter other than the first polynomial nonlinear filter sums a nonlinearly filtered input data sample produced by that polynomial nonlinear filter with the output data sample received from a neighboring polynomial nonlinear filter.08-21-2008
20080198913Equalizer - Methods and apparatus to provide an equalizer for analog adaptive control are disclosed. An example equalizer described herein includes a high frequency amplifier to receive an input signal and to amplify a high frequency portion of the input signal, a low frequency amplifier to receive the input signal and to amplify a low frequency portion of the input signal, and a weight factor controller to control a gain of the high frequency amplifier and a gain of the low frequency amplifier.08-21-2008
20080198912Equalizing Filter Circuit - In an equalizing filter circuit having an input terminal 08-21-2008
20110228837Methods and Apparatuses for Interference Cancellation with Frequency Error Compensation for Equalizer Adaptation - In accordance with an example embodiment of the present invention, a method comprises receiving a input signal comprising an interfering signal component and a desired signal component at a wireless device; estimating a frequency error of the interfering signal component; and frequency-shifting the input signal based at least in part on the estimated frequency error. The method also comprises estimating a frequency response based on the frequency-shifted input signal and a reconstructed first cancellation signal; obtaining a second cancellation signal by applying the estimated frequency response to the first cancelation signal; subtracting the second cancellation signal from the input signal; and decoding the desired signal component from the input signal after the second cancellation signal is subtracted from the input signal.09-22-2011
20130148711SOFT LINEAR AND NON-LINEAR INTERFERENCE CANCELLATION - A two stage interference cancellation (IC) process includes a linear IC stage that suppresses co-channel interference (CCI) and adjacent channel interference (ACI). The linear IC stage disambiguates otherwise super-trellis data for non-linear cancellation. Soft linear IC processing is driven by a-posteriori probability (Apop) information. A second stage performs expectation maximization/Baum Welch (EM-BW) processing that reduces residual ISI left over from the first stage and also generates the Apop which drives the soft linear IC in an iterative manner.06-13-2013
20110235695HIGH-SPEED CONTINUOUS-TIME FEEDBACK EQUALIZER FOR SERIAL LINK RECEIVER - An apparatus is disclosed, the apparatus comprising: a broad-band continuous-time adjustable weight summing cell for summing an input signal and a feedback signal into an intermediate signal in accordance with a weight factor for the feedback signal; a broad-band continuous-time delay cell for receiving the intermediate signal and outputting the feedback signal; a broad-band variable gain amplifier for amplifying the feedback signal into an output signal in accordance with a gain factor; and an adaptation circuit for adjusting the weight and the gain factor in accordance with the output signal and a timing defined by a clock signal so as to minimize an interference form a previous data to a present data embedded in the output signal.09-29-2011
20100290515Multi-Band Gain Adaptation for Receiver Equalization Using Approximate Frequency Separation - A receiver comprises equalization circuitry implementing at least first and second gain adaptation loops associated with respective first and second frequency bands. The equalization circuitry in one aspect is operative to identify a pattern in a portion of a received serial data stream, and to perform gain adaptation for the receiver utilizing a particular one of the gain adaptation loops responsive to the identified pattern. For example, the gain adaptation may be performed utilizing a low frequency gain adaptation loop if the detected pattern is of a first type generally associated with a low frequency band, and may be performed utilizing a high frequency gain adaptation loop if the detected pattern is of a second type generally associated with a high frequency band. In other aspects, the first and second gain adaptation loops may be activated in a particular serial order or in parallel.11-18-2010
20120257668TIME-VARYING LEAST-MEAN-FOURTH-BASED CHANNEL EQUALIZATION METHOD AND SYSTEM - The time-varying least-mean-fourth-based channel equalization method is an automated procedure that provides an adaptive equalizer in a CDMA receiver. Equalizer filter coefficients are estimated using a least-mean-fourth (LMF) error calculation based on a training set of symbols sent by the transmitter. When the LMF error calculation is combined with a power-of-two quantization (PTQ) process, superior receiver performance is achieved in a time-varying CDMA channel operating in non-Gaussian noise environments.10-11-2012
20100316111SIGNAL EQUALIZER FOR A SIGNAL TRANSMISSION NETWORK - In an RF signal transmission network such as the reverse channels of a coaxial cable network, there is provided at least one adaptive equalizer for pre- or post-filtering inter-symbol interference in the transmitted signals, the adaptive equalizer having a series of coefficients for which values are required. In order to improve the transmission efficiency the preamble used in these channels is shortened by coarsely estimating the channel using a short “unique word’ placed at the beginning of the equalizer training sequence. The coarse channel estimate is crudely inverted to produce a set of equalizer coefficients which partially equalize the channel. By initializing the adaptive equalizer with these approximate coefficients, it is possible to reduce the length of the training sequence needed for the equalizer to converge.12-16-2010
20100316109METHOD AND APPARATUS FOR ESTIMATING AND CORRECTING BASEBAND FREQUENCY ERROR IN A RECEIVER - A method and apparatus for estimating and correcting baseband frequency error in a receiver are disclosed. An equalizer performs equalization on a sample data stream and generates filter tap values based on the equalization. An estimated frequency error signal is generated based on at least one of the filter tap values. A rotating phasor is generated based on the estimated frequency error signal. The rotating phasor signal is multiplied with the sample data stream to correct the frequency of the sample data stream. Alternatively, a channel estimator performs channel estimation and generates Rake receiver finger weights based on at least one of the finger weights. An estimated frequency error signal is generated based on at least one of the finger weights.12-16-2010
20100316108DEVICE AND METHOD OF DATA RECOVERY - A data recovery device and a data recovery method are provided. The data recovery device includes an equalizer, a slicer, a phase lock loop (PLL) circuit, a detection circuit, and a compensation circuit. The equalizer adjusts a radio frequency (RF) signal according to a compensation signal and outputs an equalized RF signal sliced by the slicer according to a slicing level to output an AC_RF signal with segments. The PLL circuit outputs a clock according to phases of the AC_RF signal. The detection circuit calculates and outputs time intervals in the segments according to the clock and detects and outputs sampling heights in the segments. The compensation circuit selects at least two of the sampling heights, calculates a ratio of the selected sampling heights according to the outputs of the detection circuit, and outputs the compensation signal according to a result of comparison between the ratio and a corresponding reference.12-16-2010
20130182754METHOD OF EQUALIZING AN OFDM SIGNAL - A method of equalizing an OFDM signal received over a transmission channel defined by a channel matrix comprises: 07-18-2013
20120281747EQUALIZER TAP DETERMINATION - A method includes performing an operation based on transformed channel data and transformed signal data to generate a transform representation of multiple taps. The transformed channel data and the transformed signal data correspond to data received at a receiver. An inverse transform of the transform representation is determined to generate multiple taps for use at an equalizer of the receiver. At least one of the multiple taps is discarded to generate updated filter taps for the equalizer.11-08-2012
20100027604Preamble detection in a Multi-Antenna MIMO 802.16e Receiver - A preamble detector for a plurality of streams of baseband digitized signals has a plurality of preamble processors, each preamble processor coupled to an input and generating an output. Each preamble processor has an input coupled to a first delay, the output of the first delay coupled to a second delay generating an output. The first and second delay are substantially equal to a preamble part. A first multiplier generates an output from a conjugated output of the second delay output and a first delay output. A second multiplier generates an output from a conjugated first delay output and an input stream. The first and second multiplier outputs are accumulated over an interval, and the complex output of the accumulator is formed into a magnitude, thereby generating the output of each preamble processor. The outputs of the preamble processors are summed and compared to a threshold to generate a preamble detect.02-04-2010
20130188681Low Complexity MMSE Equalization Process and Equalizer for Doing the Same - Process for equalizing a signal received in a receiver of a Terminal Equipment in a wireless communication system, said process comprises the steps of:—receiving a signal r—applying an iterative algorithm based on a sequence of varying preconditionners in accordance with the following formula: based on a sequence of preconditioning matrices P07-25-2013
20130188680Providing Slope Values For A Demapper - In one embodiment, a method can provide for dynamic updating of slope values used in determining a soft decision for a demodulated signal obtained in a receiver from a broadcast signal received by the receiver. The method includes generating a channel estimate for a channel traversed by the signal, computing channel state information from the channel estimate, computing statistical information from the channel state information, determining a slope value based at least in part on the statistical information, calculating a log-likelihood ratio (LLR) value for the signal, and applying the slope value to the LLR value to obtain a weighted LLR value.07-25-2013
20120020405ELECTRONIC EQUALIZATION AND ELECTRONIC DEPOLARIZATION METHOD, RECEIVING END EQUIPMENT, AND COMMUNICATION SYSTEM - Embodiments of the present invention disclose an electronic equalization and electronic depolarization method, a receiving end equipment, and a communication system. According to the embodiments of the present invention, parameters required by electronic equalization and electronic depolarization are calculated by detecting a Synchronization Sequence (SS) in a received signal, and then the electronic equalization and the electronic depolarization are performed on the received signal in a frequency domain by utilizing the parameters, so as to solve a problem of the electronic equalization and the electronic depolarization in a Polarization Division Multiplexing (PDM) Orthogonal Frequency Division Multiplexing (OFDM) system. Furthermore, the realization complexity of the electronic equalization and the electronic depolarization performed in the frequency domain is greatly reduced relative to the electronic equalization and the electronic depolarization performed in a time domain.01-26-2012
20130202021System and Method for Polarization De-Multiplexing in a Coherent Optical Receiver - A system and method for polarization de-multiplexing in a coherent optical receiver. De-multiplexing is achieved using a modified constant modulus algorithm (CMA) wherein filter coefficients are determined as a function of a coupling coefficient to avoid convergence of the CMA outputs.08-08-2013
20130202022METHOD AND DEVICE FOR SIGNAL PROCESSING AND APPLIED TO MICROWAVE COMMUNICATION SYSTEM - A method and a device which are for signal processing and are applied to a microwave communication system are disclosed. The method includes: performing equalization processing on each input signal by using an equalizer so as to obtain an equalized signal corresponding to the each input signal; performing phase estimation on phase noise in the equalized signal to obtain an estimated phase of the phase noise; performing phase rotation on the equalized signal to offset the estimated phase of the phase noise, so as to obtain a phase rotation signal; suppressing residual phase noise in the phase rotation signal by using a phase-locked loop so as to output an error signal and a received signal; and performing an iterative update on a filter coefficient of the equalizer by using the error signal.08-08-2013
20130202023EQUALIZER FOR AM IN-BAND ON-CHANNEL RADIO RECEIVERS - A method is provided for equalizing OFDM symbol vectors received on AM in-band on-channel radio signal including a main carrier and first and second BPSK modulated subcarriers. The method comprises: computing a BPSK magnitude signal; filtering the BPSK magnitude signal; filtering complex samples received on the main carrier; using the filtered BPSK magnitude signal and the filtered complex samples received on the main carrier to compute a plurality of flat fade equalization coefficients; and multiplying the OFDM symbol vectors by the flat fade equalization coefficients. A receiver that includes an equalizer, which operates in accordance with the method is also provided.08-08-2013
20120076192EFFICIENT HIGH PERFORMANCE DEMODULATION OF LOW BT VALUE GAUSSIAN MINIMUM SHIFT KEYING INCORPORATING TURBO EQUALIZATION03-29-2012
20130208779FEED-FORWARD EQUALIZER ARCHITECTURES - Circuits and methods are provided for efficient feed-forward equalization when sample-and-hold circuitry is employed to generate n time-delayed versions of an input data signal to be equalized. To equalize the input data signal, m data signals are input to m feed-forward equalization (FFE) taps of a current-integrating summer circuit, wherein each of the m data signals corresponds to one of the n time-delayed versions of the input data signal. A capacitance is precharged to a precharge level during a reset period of the current-integrating summer circuit. An output current is generated by each of the m FFE taps during an integration period of the current-integrating summer circuit, wherein the output currents from the m FFE taps collectively charge or discharge the capacitance during the integration period. A gating control signal is applied to an FFE tap during the integration period to disable the FFE tap during a portion of the integration period in which the data signal input to the FFE tap is invalid.08-15-2013
20130208778Filter For Impulse Response Shortening With Additional Spectral Constraints For Multicarrier Transmission - A channel in a multiple carrier communication system is equalized by computing a desired spectral response, shortening the impulse response of the channel so that a significant part of an energy of the impulse response is confined to a region that is shorter than a target length and filtering the signal based on the desired spectral response. A multiple carrier communication system may include a primary impulse shortening filter that receives an output signal of an analog to digital converter and accepts coefficients. A secondary impulse shortening filter may receive the output signal of the analog to digital converter, output an output signal, and pass coefficients to the primary impulse shortening filter. A reference signal generator may output a reference signal. A comparator may compare the output signal and the reference signal and output a resulting error signal. An adaptive processor may compute coefficients for the secondary impulse shortening filter based on the error signal.08-15-2013
20130208780JOINT DEMODULATION USING A VITERBI EQUALIZER HAVING AN ADAPTIVE TOTAL NUMBER OF STATES - Systems and methods for performing joint demodulation using a Viterbi equalizer having an adaptive total number of states are disclosed. Generally, a method includes joint demodulating a desired signal and one or more interfering signals with a Viterbi equalizer having an adaptive total number of states based on channel impulse response (CIR) coefficients associated with a desired signal and the one or more interfering signals.08-15-2013
20130208781TRANSMITTER AND RECEIVER FOR FREQUENCY DOMAIN EQUALIZATION - A transmitter and/or receiver for performing frequency domain equalization is provided. A transmitter includes a pilot position determination unit for determining positions for inserting pilots in a frequency domain based on frequency spectrums of data, and a pilot insertion unit for inserting the pilots between the frequency spectrums of the data according to the determined positions for inserting the pilots.08-15-2013

Patent applications in class Adaptive

Patent applications in all subclasses Adaptive