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Automatic frequency control

Subclass of:

375 - Pulse or digital communications

375316000 - RECEIVERS

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DocumentTitleDate
20130028356HETERODYNE COMMUTATING MIXER APPARATUS - Heterodyne commutating apparatuses and methods for creating the heterodyne commutating apparatuses are disclosed. The heterodyne commutating mixer includes a plurality of switches for transferring a radio frequency input signal sequentially during a plurality of local oscillator period timeslots to a plurality of output capacitors. The heterodyne commutating mixer also includes a plurality of inductors added across differential in-phase output terminals and quadrature output terminals. Values of inductance and capacitance are set to achieve resonance at an output intermediate frequency.01-31-2013
20080273635FREQUENCY-OFFSET ESTIMATION - A device for calculating an overall frequency-offset estimate from a plurality of frequency-offset estimates includes a receiver unit configured to receive a plurality of data streams, a phase shift estimation unit configured to generate a phase shift quantity representative of a phase shift over a number of consecutive data samples in the respective data stream, and a phase shift processing unit coupled to the phase shift estimation unit and configured to calculate a quantity related to the signal-to-noise ratio associated with a data stream on the basis of the respective phase shift quantity. Further, the device includes a frequency-offset estimation unit configured to generate frequency-offset estimates associated with the respective data streams, and a combiner configured to calculate an overall frequency-offset estimate on the basis of the frequency-offset estimates and on the basis of the quantities related to the signal-to-noise ratios.11-06-2008
20090003493CORRECTING FOR CARRIER FREQUENCY OFFSET IN MULTI-CARRIER COMMUNICATION SYSTEMS - A multi-carrier (MC) receiver receives a multi-carrier signal containing data symbols as well as pilot symbols. The MC receiver estimates a carrier frequency offset in a downconverted base-band multi-carrier signal in the frequency domain based on deviations of one or more characteristics of the pilot signals from predetermined values, and corrects for the offset in the time domain. In an embodiment, a second order phase locked loop (PLL) estimates the phase of the pilot signals to determine the carrier frequency offset. Changes in pilot phases caused due to the time domain correction are cancelled to allow the PLL to minimize deviations from the lock position.01-01-2009
20090122928Apparatus and method for frequency estimation in the presence of narrowband gaussian noise - A method of compensating for a frequency estimation bias due to sampled filtered noise of a channel filter, comprises: estimating autocorrelation functions for the impulse response of the channel filter over a range of frequencies; selecting one of the frequencies for use; estimating a noise spectral density of the sampled filtered noise; reading the autocorrelation function corresponding to the selected frequency; estimating the frequency bias as a function of the noise spectral density and the autocorrelation function for the selected frequency; and using the estimate to compensate for the frequency offset. The compensated signal is useful in such standard receiver functions as, automatic gain control (AGC), timing recovery, matched filtering/equalization and phase estimation and compensation.05-14-2009
20130039451APPARATUS AND METHOD FOR CONVERTING AN ANALOG TIME DOMAIN SIGNAL INTO A DIGITAL FREQUENCY DOMAIN SIGNAL, AND APPARATUS AND METHOD FOR CONVERTING AN ANALOG TIME DOMAIN SIGNAL INTO A DIGITAL TIME DOMAIN SIGNAL - An apparatus for converting an analog signal into a digital signal includes: two identical analog-to-digital-converters converting the analog signal into first and second digital time domain signals; first and second transformation units transforming the first and second digital time domain signals into first and second digital frequency domain signals; a frequency compensation unit modifying the second frequency signal to reduce a difference between wanted signal components of the second and first frequency values caused by a difference between frequency responses of the analog-to-digital converters; a comparison unit determining for a same frequency bin corresponding first and second energy values associated to corresponding frequency values of the first and second digital frequency domain signal, and determining a minimum energy value thereof; and a selection unit selecting for a same frequency bin of the digital frequency domain signal the digital frequency domain signal associated to the minimum energy value.02-14-2013
20090116593CIRCUIT FOR PROVIDING AUTOMATIC ADAPTATION TO FREQUENCY OFFSETS IN HIGH SPEED SERIAL LINKS - Aspects of providing automatic adaptation to frequency offsets in high speed serial links are described. First signals for phase adjusts in a receiver link are adjusted by detecting trends in the first signals to generate second signals, the second signals improving a rate of compensation for the frequency offsets by the phase adjusts. An up/down counter is included for counting signals for phase adjustments by a clock-data-recovery loop of a serial receiver. An adder is coupled to the up/down counter and outputs accumulated data indicative of a trend in the phase adjustments. Combinatorial logic coupled to the adder adapts the signals based on the accumulated data.05-07-2009
20100104051COMMUNICATION SIGNAL RECEIVER FOR ESTIMATING AN IMAGINARY-PART COMPONENT OF A COMPLEX DATA SIGNAL AND METHOD THEREOF - A communication signal receiver includes a feed-forward filter and a coefficient adjusting circuit. The feed-forward filter generates an estimated imaginary-part component signal according to a real-part component of a complex data signal by using tap coefficients of the feed-forward filter. The coefficient adjusting circuit adjusts the tap coefficients of the feed-forward filter according to a control information, wherein the control information comprises a phase error information. The phase error information changes as a phase of the complex data signal changes, wherein the phase is adjusted or not adjusted by the coefficient adjusting circuit.04-29-2010
20090154616RESIDUAL FREQUENCY OFFSET COMPENSATION APPARATUS USING PHASE SHIFT COMPENSATION SCHEME - A residual frequency offset compensation apparatus is provided. The residual frequency offset compensation apparatus includes: a basic phase offset compensation unit compensating input symbols using a previously stored basic phase offset and generating first symbols; a phase shift calculation unit calculating a phase shift value of each of a predetermined number of the first symbols using first detection symbols and the first symbols, the first detection symbols being generated by detecting the first symbols; a phase shift compensation unit compensating the first symbols based on an average of the phase shift values; and a basic phase offset update unit updating the basic phase offset based on the phase shift values.06-18-2009
20090154615INTEGRATED CIRCUIT FOR PROCESSING MULTI-CHANNEL RADIO SIGNAL - A multi-channel radio signal processing integrated circuit (06-18-2009
20090154614METHOD AND APPARATUS FOR DETECTING A FREQUENCY BAND AND MODE OF OPERATION - A method and apparatus for detecting a frequency band and mode of operation using recursive sampling and narrowing down is disclosed. The method comprises sampling (06-18-2009
20090154613TIMING-FREQUENCY OFFSET AND CARRIER-FREQUENCY OFFSET ESTIMATIONS FOR MULTI-CARRIER MODULATED SIGNALS USING PILOT TONES - In one embodiment, a demodulator demodulates a multi-carrier modulated signal having two pilot tones. The demodulator calculates a first phase angle for the first pilot tone and a second phase angle for the second pilot tone based on the time-domain multi-carrier modulated signal. A timing-frequency offset estimate is calculated using the first and second phase angles. Further, a fine carrier-frequency offset estimate is calculated for each pilot tone based on the corresponding phase angle and the timing-frequency offset estimate. Each fine carrier-frequency offset estimate is combined with a coarse estimate and weighted. The weighted estimates are then combined. In further embodiments, the timing-frequency offset estimate is weighted and combined with a weighted timing-frequency offset estimate generated using a cyclic prefix. In yet further embodiments, the weighted carrier-frequency offset estimates are combined with a weighted carrier-frequency offset estimate generated using a cyclic prefix.06-18-2009
20090154612METHOD AND SYSTEM FOR DYNAMIC FILTERING AND DATA CONVERSION RESOLUTION ADJUSTMENTS IN A RECEIVER - Aspects of a method and system for dynamic filtering and data conversion adjustments in a receiver are provided. Exemplary aspects of the invention may include a receiver comprising a data converter and one or more filters, and a resolution of the data converter and/or a frequency response of the filters may be varied/configured (e.g., via one or more switching elements) based on one or more characteristics of a received signal. The received signals may be amplified and/or filtered prior to determining the characteristics. The resolution of the data converter and/or a quality factor of one or more of the filters may be reduced when measured interference is below a threshold and increased when measured interference is above a threshold. The resolution of the data converter and/or the frequency response of the filter may be determined based on an error rate associated with the received signals.06-18-2009
20130083874AUTOMATIC FREQUENCY COMPENSATION METHOD AND APPARATUS - A method an apparatus for performing automatic frequency compensation (or control) is disclosed. A method and apparatus for performing automatic frequency compensation (or control) is disclosed. In one embodiment, a method includes a radio receiver receiving a radio signal and detecting a preamble in the radio signal. The method further includes freezing an automatic frequency compensation (AFC) loop responsive to detecting the preamble. A clock source of the AFC loop may be switched from a first clock signal to a second clock signal. The method further includes subsequently unfreezing the AFC loop.04-04-2013
20110058633APPARATUS AND METHOD FOR NON-NETWORK CHANNEL SCANNING IN DIGITAL VIDEO BROADCASTING SYSTEM - An apparatus and a method for commonly applying channel scanning to non-network scanning schemes in a digital video broadcasting system are provided. The method includes deleting all services stored in a database, temporarily storing services scanned through each frequency in a temporary storage unit, and performing channel scanning for all frequencies. Accordingly, the same service including different Logical Channel Numbers (LCNs) that is repeatedly stored or another service including the same LCN that is not stored in a Multi Frequency Network (MFN) boundary area using the non-networking scanning scheme is prevented.03-10-2011
20090060100WIRELESS COMMUNICATION APPARATUS AND WIRELESS COMMUNICATION METHOD - A wireless communication apparatus capable of enhancing the transmission efficiency, while maintaining a good BER characteristic. In this apparatus, a setting part (03-05-2009
20090238312System And Method For Tuning A Radio Receiver - A system for tuning a radio receiver includes a radio receiver configured to provide a downconverted digital error signal, a digital synthesizer circuit configured to generate a first local oscillator control signal, a digital automatic frequency control (AFC) circuit configured to generate a second local oscillator control signal, wherein the digital synthesizer circuit is enabled to generate the first local oscillator control signal when the digital AFC circuit is disabled, the first local oscillator control signal corresponds to an estimate of a desired local oscillator frequency, the digital AFC circuit is enabled to generate the second local oscillator control signal when the digital synthesizer circuit is disabled and the second local oscillator control signal corresponds to the desired local oscillator frequency.09-24-2009
20090232259RECEIVER AND ELECTRONIC APPARATUS - A receiver has a receiving unit including a PLL, a mixer, and a filter, and demodulating unit including a frequency error detector for detecting a frequency error in a signal from a filter. The PLL includes a local oscillator for supplying a local oscillation signal to a mixer, a variable frequency divider for frequency-dividing the local oscillation signal based on a signal from the frequency error detector, and a phase comparator for comparing a signal from the variable frequency divider with a signal from a crystal oscillator. The PLL can reduce the frequency error of the local oscillation signal.09-17-2009
20110019782SIGNAL PROCESSING APPARATUS AND METHOD - Disclosed herein is a signal processing apparatus, including: a computation device operable to perform transform computation adapted to Fourier-transform a time domain OFDM i.e., Orthogonal Frequency Division Multiplexing signal into a frequency domain OFDM signal; a processing device operable to perform carrier frequency offset detection adapted to detect an estimated carrier frequency offset that is an error of a carrier used for demodulation of the OFDM signal; and a carrier frequency offset correction device operable to perform carrier frequency offset correction adapted to correct the carrier frequency offset of the frequency domain OFDM signal in accordance with the estimated carrier frequency offset.01-27-2011
20110135042Blind scan system and method in a DVB-S system - A blind scan system in a DVB-S system includes a spectrum parameter extractor to fetch and calculate a coarse carrier frequency offset and coarse symbol rate of a signal; a digital mixer to depend on the coarse frequency offset to shift the center of a spectrum of the signal to a position where a DC part of a working spectrum of a digital matched filter locates, so as to produce an offset signal; and an interpolator to perform a down-sampling on the offset signal according to the coarse symbol rate in order to improve the in-band signal-to-noise ratio of the digital matched filter and mitigate impacts due to adjacent channel interferences. Thus, the fine carrier frequency offset and fine symbol rate estimation can be performed accurately.06-09-2011
20110280349APPARATUS & METHODS FOR SYMBOL TIMING ERROR DETECTION, TRACKING AND CORRECTION - Systems and methods for adjusting timing in a communication system, such as an OFDM system are described. In one implementation an error signal is generated to adjust the timing of a variable rate interpolator so as to adjust FFT timing. The error signal may be based on detection of significant peaks in an estimate of the impulse response of the channel, with the peak locations being tracked over subsequent symbols and the system timing adjusted in response to changes in the peaks.11-17-2011
20080279313Sample clock frequency offset estimation in DRM - A system and method for estimating sample clock frequency offset (ε11-13-2008
20110299639AUTOMATIC FREQUENCY OFFSET COMPENSATION METHOD AND DEVICE - The disclosure aims to implement an automatic frequency offset compensation of the frequency between emitter and receiver equipments, in radio frequency modules, with a frequency offset that can be larger than that the receiver can allow, without time loss and extra consumption. To solve this problem, the disclosure provides an automatic frequency offset compensation device comprising a reception front end, at least a filter, an I/Q demodulator for obtaining the I (In Phase) and Q (Quadrature) parameter, an automatic frequency control AFC unit for comparison of a received frequency with the real frequency of the equipment, and a microcontroller and a frequency synthesizer. In this device, the frequency offset is calculated by the AFC unit from the information given by the I/Q demodulator. A coarse detection with wide filter can be used for the reception of the first part of the data called preamble signal, and a fine detection with narrow filter can be used for reception of the second part of the data called useful data frame. A frequency synthesis is made using the frequency offset12-08-2011
20090022252Channel response calculation in an OFDM receiver - An efficient algorithm is described for use with OFDM receivers that characterizes the impulse response of a communication channel using frequency domain techniques that reduce computational and memory requirements, relative to time-domain cross-correlation methods, without sacrificing algorithm performance. An FFT engine is used to transform a time domain input sequence, the transformed sequence is multiplied by the conjugate of the expected sequence, the product of several sequences is averaged, then the FFT engine transforms the average back to a time domain sequence, the magnitude of which is the impulse response of the channel.01-22-2009
20110293049Method and Apparatus for Receiver Frequency Error Compensation - This disclosure presents a receiver apparatus (12-01-2011
20110293048Quadrature gain and phase imbalance correction - Generally speaking, methods and apparatuses which correct errors related to phase and gain imbalances in quadrature tuners are disclosed. The quadrature tuner may be online and operating, receiving data. An embodiment may generate a squared signal from the IF frequency signal of the tuner. In generating the squared signal, the embodiment may enable the extraction of phase error and gain error information of the IF signal. The embodiment may determine a phase error component, a gain error component, or both, by frequency translation. The frequency translation may involve down-converting the signal associated with the error component to direct current (DC) signals and enable the determination of the associated phase error and/or gain error. The embodiments may generate an adjusted signal via the IF signal by applying a phase correction signal or gain correction signal to components used to correct the IF signal.12-01-2011
20090097597Methods For Coarse Frequency Offset Estimation For Orthogonal Frequency Division Multiplexing Schemes - The present invention provides methods for coarse frequency offset estimation, where those methods may comprise the steps of: removing fading channel impact by calculating accumulated correlation values; removing CCI and phase rotation due to large sampling offset by calculating an accumulation metric as a function of the accumulated correlation values, CCI peak, and initial sampling offset, ξ; and finding the coarse frequency offset as a function of the accumulation metric.04-16-2009
20100119019RECEIVING APPARATUS AND METHOD, PROGRAM AND RECORDING MEDIUM USED FOR THE SAME - A receiving apparatus according to the present invention includes a filter control portion 05-13-2010
20090086856RECEPTION FREQUENCY CONTROL CIRCUIT - The present invention aims to provide a reception frequency control circuit that is small in mounting area and unaffected by disturbance where an FSK-modulated signal is demodulated. In the reception frequency control circuit, a reception signal processing unit converts an FSK-modulated digital signal to an intermediate frequency when the FSK-modulated digital signal is received. Thereafter, a frequency voltage converting unit converts the intermediate signal to a voltage signal and outputs an output signal. At the same time, an analog frequency controlling unit detects a frequency deviation from the output signal by analog processing. A digital frequency controlling unit generates a reception frequency control signal for correcting the frequency and feeds back the same to the reception signal processing unit. Stable frequency control can be realized by performing reception frequency control by a combination of an analog circuit-digital circuit in this way.04-02-2009
20090190698RECEIVER, RECEIVING METHOD, AND USE OF AN IN-PHASE SIGNAL AND A QUADRATURE-PHASE SIGNAL - A receiver, receiving method, and use of an in-phase signal and a quadrature-phase signal is provided, that includes a mixer in the receiving path, an oscillator whose output is connected to a mixer input of the mixer, whereby the oscillator is formed to output a base signal, oscillating at a base frequency, at the output, a clock generation device to generate a clock signal from the base signal, whose input is connected to the output of the oscillator, whereby the clock generation device has a frequency converter for converting a base frequency of the base signal by the factor F=x+A, where x is a positive whole number and A a rational number between 0 and 1, and a signal processing device, which is connected downstream of the mixer in the receive path, whereby the signal processing device is connected to the clock generation device for control with the clock signal.07-30-2009
20090141838APPARATUS AND METHOD FOR AUTOMATICALLY CHANGING BROADCAST CHANNEL FOR MOBILE COMMUNICATION TERMINAL ADAPTED TO RECEIVE DIGITAL MULTIMEDIA BROADCAST - Disclosed is an apparatus and a method for automatically changing the broadcast channel for a mobile communication terminal adapted to receive digital multimedia broadcasts. The apparatus includes a memory unit for storing an adjacent area database and an area-wise broadcast channel database; a search unit for searching for broadcast channels and receiving broadcasts; and a control unit for determining the received field strength of at least one adjacent area frequency based on the adjacent area database during digital multimedia broadcast playback, and when a predetermined threshold is exceeded, determining that a movement into a corresponding adjacent area is occurring, the control unit controlling the search unit to search through broadcast channels of the adjacent area in the area-wise broadcast channel database to find a broadcast channel identical to a broadcast channel used for playback before the movement into the adjacent area.06-04-2009
20090274250METHOD AND APPARATUS FOR ESTIMATING CARRIER FREQUENCY OFFSET - In order to improve precision for estimating carrier frequency offset and reduce computing load, the present invention provides a method for estimating carrier frequency offset, which comprises steps of calculating a plurality of corresponding intermediate CFOs, respectively, based on one received sync sequence and one prestored sync sequences stored sync sequence through multi-step calculation, wherein, in each step, one corresponding intermediate CFO is calculated based on said received sync sequence and said pre-stored sync sequence; and weighting said plurality of intermediate CFOs in accordance with channel quality of a channel transmitting said received sync sequence to generate one final CFO. Each of the selected sequence segments may have a length and a mutual distance which are both, at its maximum, the full length of the sync sequence minus 1 so as to improve precision for the intermediate CFOs. Further, the estimation precision for the final CFO is improved by considering the impact of quality difference of reception channels on the intermediate CFOs.11-05-2009
20090290664RECEIVER FOR WIRELESS COMMUNICATION NETWORK WITH EXTENDED RANGE - Techniques for detecting and demodulating a signal/transmission are described. Signal detection is performed in multiple stages using different types of signal processing, e.g., using time-domain correlation for a first stage, frequency-domain processing for a second stage, and time-domain processing for a third stage. For the first stage, products of symbols are generated for at least two different delays, correlation between the products for each delay and known values is performed, and correlation results for all delays are combined and used to declare the presence of a signal. For demodulation, the timing of input samples is adjusted to obtain timing-adjusted samples. A frequency offset is estimated and removed from the timing-adjusted samples to obtain frequency-corrected samples, which are processed with a channel estimate to obtain detected symbols. The phases of the detected symbols are corrected to obtain phase-corrected symbols, which are demodulated, deinterleaved, and decoded.11-26-2009
20100128825APPARATUS AND METHOD FOR EFFICIENT INTER RADIO ACCESS TECHNOLOGY OPERATION - An apparatus, and a method performed by the apparatus, including a terminal with a front end receiver and analog filter (AF) operable throughout a bandwidth that is large enough to cover the total bandwidth used by different access technologies that the terminal supports. The terminal is operable to simultaneously extract from the output of a single front end receiver and AF the carrier frequencies and bandwidths of the different access technologies. This permits cell evaluation activity and an ongoing communication session to be conducted simultaneously with different access technologies on different bandwidths within the bandwidth of the analog filter and without interruption of the communication session.05-27-2010
20100128824BLIND FREQUENCY-OFFSET ESTIMATION FOR TEMPORALLY AND/OR SPATIALLY CORRELATED SIGNAL - An iterative, blind, frequency-offset estimation process that does not require any training signal or demodulated information symbols is disclosed. Receivers embodying the disclosed processes can produce periodic frequency-offset estimates, without running computationally intensive equalization or demodulation algorithms, by exploiting the temporal correlation of the received signal in the time domain, as well as the received signal's correlation across in-phase and quadrature dimensions, in some embodiments, to find a frequency-offset estimate that best fits the received signal in a maximum-likelihood sense. In an exemplary method of estimating receiver frequency offset, a temporally stacked signal block is formed from multi-branch signal samples corresponding to each of two or more time-separated samples of the received signal. The temporally stacked signal block is used in computing a maximum-likelihood joint estimate of the receiver frequency offset and the spatial covariance of the temporally stacked signal block de-rotated by the receiver frequency offset.05-27-2010
20100135440SIGNAL COMPONENT DEMULTIPLEXING APPARATUS, FILTER APPARATUS, RECEIVING APPARATUS, COMMUNICATION APPARATUS, AND COMMUNICATION METHOD - A filter apparatus extracts a specific signal from a group of multi-carrier modulated signals. A complex sine wave signal is outputted in accordance with a channel to be selected. The complex sine wave signal and an input group of signals are multiplied. A specific group of signals is selected from a result of the multiplication and is rearranged along a frequency axis.06-03-2010
20080279314Digital Radio Mondiale receiver integer carrier frequency offset estimation - A method and apparatus for estimating a carrier frequency offset (CFO) in a Digital Radio Mondiale receiver is provided. Orthogonal frequency-division multiplexing (OFDM) demodulation is performed on a received DRM signal to produce OFDM symbols. A cell characteristic in corresponding cells in the OFDM symbols is compared and a carrier index of a frequency pilot cell in the cells is identified based upon the compared cell characteristic. The CFO is estimated based on the identified carrier index of the frequency pilot cell. The ratio of values of the cell characteristic in corresponding cells may be calculated and the frequency pilot cell identified by identifying cells for which the cell characteristic is most nearly equal. The CFO may be estimated by comparing the identified carrier index with an expected carrier index of a frequency pilot cell.11-13-2008
20080285689START-UP AUTOMATIC FREQUENCY CONTROL (AFC) METHOD AND APPARATUS - A method and apparatus for use in connection with wireless communication to adjust the frequency of an oscillator to synchronize with a received signal by correlating a synchronization code channel with training sequences to estimate relative offsets which are employed to estimate an error, which is then filtered. The filtered output preferably provides a voltage controlling a voltage controlled oscillator (VCO). The same technique may be employed to control a numeric controlled oscillator (NCO).11-20-2008
20080240311Frequency offset correction - A frequency error correction scheme applicable in a receiver of a mobile telecommunication system is presented. The present frequency error correction scheme is carried out in a time domain after an equalization process. The present frequency error correction scheme may be applied to a base station receiving signals transmitted according to a single-carrier frequency division multiple access communication scheme. The separation of different received signals for further processing is carried out in the frequency domain before the equalization and the frequency error correction.10-02-2008
20080253486FREQUENCY CORRECTION - A frequency correction circuit that gives plural frequency offsets to a received radio signal in order to correct a frequency error of the radio signal, demodulates the radio signal, combines an arbitrary number of demodulation signals as combined demodulation signals from among plural demodulation signals, and selects one demodulation signal or combined demodulation signal from among the demodulation signals and the combined demodulation signals.10-16-2008
20110007854INTEGER CARRIER FREQUENCY OFFSET ESTIMATION SCHEME FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING - A coarse integer carrier frequency offset CFO compensator (01-13-2011
20080232516METHOD OF FREQUENCY OFFSET COMPENSATION - The present invention provides a method of processing a baseband signal including user signals transmitted by a plurality of users. The method includes applying frequency offset compensations to the baseband signal, thereby to form respective frequency-shifted baseband signals. Each frequency compensation shifts the baseband signal by a multiple of a selected frequency offset and each resulting frequency-shifted baseband signal includes frequency-shifted user signals. The method also includes assigning at least some of the frequency-shifted user signals to groups. Each group corresponds to one of the frequency compensations and the assignment is carried out so that each group includes frequency-shifted user signals that have an estimated frequency offset that lies within a range determined by the corresponding frequency compensation. The method further includes estimating a frequency offset of each of the user signals based on the frequency-shifted user signal and the frequency compensation of the group including the frequency-shifted user signal.09-25-2008
20090003494RADIO COMMUNICATION SYSTEM AND APPARATUS - A radio communication system for transmitting a radio signal with a transmission format in which a channel response calculation preamble signal serving as a reference upon reception is inserted is disclosed. The output frequency of channel response calculation preamble signals is varied in accordance with a temporal change in radio propagation environment. A channel response variation measurement unit measures a variation of the radio propagation environment. A channel response calculation preamble signal output frequency setting unit sets the output frequency of preamble signals in accordance with the temporal change in radio propagation environment. The preamble signals are inserted in the transmission format to be transmitted at that frequency.01-01-2009
20110268232INTER-CARRIER BANDWIDTH CONTROL FOR MITIGATING IQ IMBALANCE - Digital IQ imbalance estimation and compensation is facilitated by shaping the frequency response of receiver branches. In particular, in a multi-carrier receiver, the frequency response of signal processing elements in at least one receiver branch is set to not fully attenuate received signals in a frequency band of interest. The frequency band of interest is greater than the carrier bandwidth of the received signal processed by that receiver branch. In some embodiments, the received signal is not attenuated, and adjacent interfering signals are partially attenuated. This allows information regarding the interfering signals to appear in an IQ imbalance-induced, inter-carrier image of the signals in anther receiver branch, facilitating digital estimation and compensation of IQ imbalance.11-03-2011
20080240309EFFICIENT AND FLEXIBLE NUMERICAL CONTROLLED OSCILLATORS FOR NAVIGATIONAL RECEIVERS - Provided herein are systems and methods for achieving long integration of an input signal by compensating the frequency and phase of each sample of the input signal. In an embodiment, a Numerical Controlled Oscillator (NCO) of the receiver is modified to include a variable control input that allows the output frequency of the NCO to be adjusted based on a rate of change of frequency. The rate of change of frequency may be estimated based on the relative velocity of a satellite to the receiver computed from satellite orbit parameters or ephemeris. The rate of change of frequency may also be estimated based on frequency measurements of previous samples. The modified NCO may be used as a carrier NCO or code NCO of the receiver to provide frequency and phase compensation of each sample of the input signal.10-02-2008
20080240310METHOD FOR ESTIMATING AND COMPENSATING FREQUENCY OFFSET AND FREQUENCY OFFSET ESTIMATION MODULE - A method for estimating frequency offset is provided. First, a baseband signal with a preamble featuring quasi-periodic property is received. Next, the quasi-periodic property of the preamble of the received baseband signal is reconstructed by interpolation. Next, a frequency offset angle is estimated by using the reconstructed baseband signal. The accuracy of estimating frequency offset is increased because of better reconstructed quasi-periodic property of the preamble.10-02-2008
20090161801RECEIVER WITH DISCRETE-TIME FILTERING AND DOWN-CONVERSION - A receiver with discrete-time filtering and down-conversion is provided. The receiver includes a mixer and a sampling-and-filtering device. The sampling-and-filtering device is coupled to the mixer. The mixer receives a first radio frequency signal, and then mixes the first radio frequency with a reference signal to generate a first signal. The first signal is a continuous-time signal. The sampling-and-filtering device sequentially samples, filters, and down-converts the first signal according to a clock signal to generate a second signal.06-25-2009
20090185647PRECISE FREQUENCY ESTIMATION OF SHORT DATA BURSTS - The invention performs frequency estimation over both the burst preamble, during which known symbols are transmitted, and also during the burst's data packet, which is subsequent to the preamble and extracted by the local detector. During the preamble, an initial frequency estimate is obtained. This estimate is based on a time average of either phase or correlation samples. Atypical phase or correlation samples, attributable to detector symbol errors during the data packet, are detected and filtered, so as to avoid including the atypical samples in a time-averages used to provide the frequency estimate. In a first embodiment correlation samples are time averaged, and atypical correlation samples are suppressed prior to correlation time averaging. In a second embodiment, phase slope values are time averaged, and atypical values of phase slope are suppressed prior to phase slope time averaging.07-23-2009
20100172449METHOD AND/OR APPARATUS FOR STABILIZING THE FREQUENCY OF DIGITALLY SYNTHESIZED WAVEFORMS - An apparatus including a first circuit, a second circuit, a third circuit and a fourth circuit. The first circuit may be configured to generate a demodulated signal in response to (i) a modulated signal and (ii) a seed value. The said seed value may be selected in response to a first control signal. The second circuit may be configured to generate a second control signal in response to the demodulated signal. The third circuit may be configured to generate the first control signal in response to (i) the second control signal, (ii) a compensation signal, and (iii) the first control signal, where (a) generation of the first control signal may include adding the second control signal, the compensation signal, and a latched version of the first control signal, (b) generation of the latched version of the first control signal may include sampling the first control signal in response to a clock signal, and (c) the compensation signal may compensate for variation in the clock signal.07-08-2010
20090080576ENHANCED CARRIER FREQUENCY OFFSET ESTIMATOR - A method is provided for estimating a frequency offset in a carrier signal caused by the Doppler effect. The method determines a frequency offset estimate by utilizing a multi stage estimation scheme. More specifically, the method determines the frequency offset estimate of a data frame by iteratively estimating the frequency offset by comparing different portions of the preamble. As the length of the sampled patterns varies, the frequency offset estimates vary in accuracy and range. The method may adjust frequency offset estimates that are out of range. Finally, the receiver obtains a frequency offset estimate for the data frame from a weighted combination of frequency offset estimates. This method is applicable in WiFi (IEEE 802.11a/g), WiMax (IEEE 802.16), and WAVE (IEEE 802.11p) systems.03-26-2009
20090252262SYMMETRIC PILOT PROCESSING FOR ROBUST TIMING OFFSET AND FREQUENCY OFFSET ESTIMATION IN ISDB-T AND ISDB-TSB RECEIVERS - Timing and frequency offset processing in sub-carriers is performed in an Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) receiver system. Sub-carriers are divided into two sub-sets, where the sub-sets contain an equal number of sub-carriers. Subsequently bad sub-carriers are removed, if present, from first sub-set of the sub-sets, and corresponding sub-carriers from a second sub-set of the sub-sets are also removed. Further, a phase difference on each sub-carrier from each sub-set is computed, and mean phase differences of each of the sub-sets are computed. Furthermore, frequency offset is computed by averaging the mean phase differences of the sets.10-08-2009
20090245437SAMPLE RATE CONVERTER AND RCEIVER USING THE SAME - A sample rate converter includes a multiplexer to select either one of an input signal and a first feedback signal, and to obtain a selected input signal, a decimator performing decimation on an Nth-order integration signal to generate an output signal, an interpolator performing interpolation on the output signal to generate a second feedback signal, a multiplier which multiplies the second feedback signal by a coefficient to generate a multiplication signal, a subtractor which subtracts the multiplication signal from the selected input signal to generate a residual signal, an adder which adds the residual signal to a third feedback signal to sequentially generate 1st-order to Nth-order integration signals, a register circuit configured to hold the integration signals, a multiplexer to select the first feedback signal from the integration signals that the register hold, and a multiplexer to select the third feedback signal from the integration signals that the register hold.10-01-2009
20100054379BURST DEMODULATOR - A burst demodulator. Implementations may include a first frequency estimating module adapted to remove a first frequency offset from a plurality of data samples. A second frequency estimating module may be coupled with the first frequency estimating module and may be adapted to remove a second frequency offset from the plurality of data samples. A third frequency estimating module may be coupled with the second frequency estimating module and may be adapted to remove a third frequency offset from the plurality of data samples. A clock phase estimating module may be coupled with the third frequency estimating module and may be adapted to calculate a clock phase offset value, select one or more coefficients for a finite impulse response (FIR) filter, and process the plurality of data samples with the FIR filter. A data processing module may be adapted to recover the data included in the plurality of data samples.03-04-2010
20090252263ESTIMATING DOPPLER FREQUENCY IN ISDB-T SYSTEMS - A technique for estimating maximum Doppler frequency of a wireless signal in a wireless communication system, wherein the method comprises receiving a wireless signal; determining an impulse response of the received wireless signal; determining an auto-correlation function (ACF) value of the impulse response of the received wireless signal; determining a power spectrum density of said received wireless signal based on the ACF value; and selecting an algorithm for performing demodulation of the received wireless signal by utilizing the determined power spectrum density.10-08-2009
20090257533SYSTEM AND METHOD OF RECEIVING AND PROCESSING MULTICOMMUNICATION SIGNALS - A receiver receives and front-end processes a plurality of component carrier signals, each carrier spaced apart in frequency. The digitized, baseband component carrier signals are inspected to determine estimates of timing offsets between the carriers. A control unit selects a first component carrier signal having data scheduled to the receiver. If data is scheduled to the receiver on other component carrier signals, the control unit generates timing and frequency offset adjustment control signals to time- and frequency-align each other component carrier signal having relevant data, to the first component carrier signal. All the relevant component carrier signals are then combined, and a single OFDM symbol, spanning all the relevant component carriers, is presented to an FFT for symbol detection.10-15-2009
20090257534Frequency Offset Estimating Apparatus and Estimating Method Thereof - A frequency offset estimating apparatus includes an nth power computing module and a spectrum analyzing module. By raising a received signal to nth power to generate an nth power signal and analyzing the spectrum of the nth power signal, the present invention is capable of quickly and accurately estimating a frequency offset of the received signal. As being unaffected by channel characteristics, the estimating frequency offset apparatus is suitable for all channel environments.10-15-2009
20090274249RADIO-FREQUENCY RECEIVER AND INTEGRATED CIRCUIT EMPLOYED FOR THE RECEIVER - Radio-frequency receiver contains a plurality of oscillation circuits that generates an oscillation frequency higher than that of digital broadcasting signals, selective switching circuit that selects two out of the oscillation circuits for signal output, and first and second frequency-divider sections that provide the signals with frequency dividing. The receiver receives two channels in the digital broadcasting signals at the same time by selection of oscillation signals and frequency dividing in the first and the second frequency-divider sections under the control of PLL controller.11-05-2009
20120140859METHOD AND CONTROL UNIT FOR DIRECT SAMPLING OF A PLURALITY OF RADIO BANDS - A method for direct sampling of a plurality of radio bands, including a step of receiving a first radio band via a first interface and at least one additional radio band via at least one additional interface, the first radio band and the at least one additional radio band each being associated with different frequency ranges, and the first radio band or the at least one additional radio band being a DAB band. Furthermore, a selection signal is received via an interface, the selection signal indicating whether further processing of the first radio band and/or the at least one additional radio band takes place. Depending on the selection signal, the first radio band is sampled at a common sampling frequency and/or the at least one additional radio band is sampled at the common sampling frequency.06-07-2012
20090116592RECEIVER AND CHANNEL ESTIMATION METHOD - An extrapolation method to suppress degradation of characteristics of channel estimation is provided.05-07-2009
20100189202RADIO SIGNAL DEMODULATING DEVICE - It is an object of the present invention to provide a radio signal demodulating device in which fluctuation followability of transmission channel environment is improved. The radio signal demodulating device according to the present invention receives the amplitude of an information signal in which known pilot signals are multiplexed, as a radio signal modulated in proportion to the time change of frequency of a carrier wave. The radio signal demodulating device according to the present invention includes a frequency converting unit, a signal combining unit, a first pilot signal extracting unit, a second pilot signal extracting unit, a first pilot orthogonal signal generating unit, a second pilot orthogonal signal generating unit, a first error signal generating unit, a first weight factor updating unit for calculating a weight factor to be used in the signal combining unit, by using a first pilot orthogonal signal and a first error signal obtained by the first error signal generating unit.07-29-2010
20100239054Receiver apparatus for absorbing clock difference between transmitting and receiving sides and a method therefor - Data received by a receiver is processed at a sampling rate indicated manually or automatically in the receiver. The sampling rate of the received data is controlled in accordance with the processing rate. The sampling rate controlled data is then processed so as to convert its frequency distribution to that the received data originally had.09-23-2010
20130216009CHANNEL-SENSITIVE POWER CONTROL - A communication receiver which applies signal processing for quantitatively estimating receive signal factors such as communication channel quality, signal characteristics, and overall system received bit error rate (BER)or packet error rate (PER) and which applies a general algorithm for mapping these estimated factors to control receiver performance and minimize power consumption.08-22-2013
20100135441SIGNAL COMPONENT DEMULTIPLEXING APPARATUS, FILTER APPARATUS, RECEIVING APPARATUS, COMMUNICATION APPARATUS, AND COMMUNICATION METHOD - A filter apparatus extracts a specific signal from a group of multi-carrier modulated signals. A subcarrier is selected. A specific group of signals is selected from among an input group of signals in accordance with the selected subcarrier. A frequency offset of a selected signal is compensated.06-03-2010
20090290663COARSE FREQUENCY OFFSET ESTIMATION FOR DIGITAL MULTIMEDIA BROADCASTING - A method of estimating a coarse frequency offset of Digital Multimedia Broadcasting (DMB) transmission frames includes receiving the DMB transmission frames including a synchronization channel having a phase reference symbol, circularly shifting the phase reference symbol by applying a circular shift to the phase reference symbol, numerically correlating the circularly shifted phase reference symbol with a known correct phase reference symbol to obtain a highest peak and a side peaks of the numeric correlation, and computing a phase reference symbol angle based on a multiplication of the peak and a carrier spacing of the DMB transmission frames. The peak is determined when the circularly shifted phase reference symbol is equal to the known correct phase reference symbol. The peak and side peaks corresponding to the peak are operated in a range of a maximum value of the circular shift.11-26-2009
20100266076FREQUENCY OFFSET ACQUISITION METHOD AND APPARATUS THEREOF - A frequency offset acquisition method includes: receiving a specific sequence signal transmitted through a channel; shifting a frequency of the specific sequence signal at a plurality of different frequencies in frequency domain to thereby generate a plurality of shifted sequence signals respectively; and determining an estimated frequency offset value between a transmitter and a receiver according to the shifted sequence signals.10-21-2010
20100220819METHODS AND SYSTEMS USING FINE FREQUENCY TRACKING LOOP DESIGN FOR WIMAX - Certain embodiments of the present disclosure relate to a method for tracking of a carrier frequency offset. A soft combined frequency tracking discriminator is proposed as a part of the closed loop structure that can provide fast tracking of the frequency offset in an initial pull-in mode, and can also track small residual frequency variance in a fine-tracking mode.09-02-2010
20090110127RECEPTION APPARATUS, RECEPTION METHOD AND PROGRAM - A reception apparatus includes: an extraction section; a transmission line characteristic estimation section; an estimation section; a frequency shift amount production section; a control section; an addition section; a first frequency shifting section; a second frequency shifting section; an interpolation section; a compensation section; a detection section; and an operation section.04-30-2009
20110110471METHOD OF BANDPASS SAMPLING USING SINGLE SIDEBAND CONVERTING - The present invention provides a method of bandpass sampling which particularly includes the single-sideband signal conversion procedure prior to the sampling process in the purpose of lowering the required sampling frequency. Conversion of the bandpass RF signal into a single-sideband spectrum signal which has the spectrum components only in either the positive or the negative frequency domain is accomplished by bandpass-filtering, or more effectively by using a Hilbert transformer. This invention includes a method of finding the minimum sampling frequency for simultaneous frequency down-conversion of multiple RF bandpass signals. It is expected from this invention that the components additionally required in the RF receiver due to the proposed bandpass sampling method is the bandpass filters or the Hilbert transformer for single-sideband conversion, but the benefits from this invention could be the reduced ADC speed performance and the subsequent digital processing load in the receiver system because of the reduced data rates.05-12-2011
20110019783RECEIVER AND ELECTRONIC DEVICE USING THE SAME - A receiver includes an oscillator for generating a local oscillator signal, a frequency converter for heterodyning a received signal of one frequency band or a plurality of frequency bands into an intermediate frequency (IF) signals with using the local oscillator signal, a filter connected to an output of the frequency converter and having a cut-off frequency changeable, an analog-digital (AD) converter connected to an output of the filter to convert an analog signal of one frequency band or a plurality of frequency bands into a digital signal, a pre-stage detector connected to an output of the AD converter or connected between the filter and the AD converter to detect a signal level, and a controller for controlling the cut-off frequency of the filter based on the signal level detected by the pre-stage detector.01-27-2011
20100142660DIGITAL FREQUENCY LOCKED DELAY LINE - A device includes a signal generator having a delay locked circuit for providing a number of output signals based on an input signal. The output signals have a fixed signal relationship with each other and with the input signal. The signal generator also includes a selector for selecting an enable signal from a range of signals formed by the output signals. The device further includes a transceiver circuit in which the transceiver circuit uses the enable signal for data processing.06-10-2010
20100135439Integrated interference cancellation system architecture with distortion connection - A system and associated method is provided for improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath. A system of the invention includes a common feedback junction, (i.e., a single sampling point used by all parameter matching control loops), for adjusting a number of distortion matching circuits while advantageously maintaining independence of tuning and other independent circuit actions.06-03-2010
20120243646FREQUENCY OFFSET COMPENSATION APPARATUS - According to one embodiment, a frequency offset compensation apparatus includes a first estimation unit, a second estimation unit, a setting unit, a synthesis unit and a compensation unit. The first estimation unit estimates a first rotation. The second estimation unit estimates a second rotation. The setting unit sets a weighting factor for the second rotation to a first value if a received power is less than a threshold value, and sets the weighting factor for the rotation to a second value being smaller than the first value if the received power is not less than the threshold value. The synthesis unit calculates a compensation value. The compensation unit compensates for a frequency offset.09-27-2012
20110129045Method and device for aquiring a channel with frequency offset less than half symbol rate - A method and device for acquiring a channel with a frequency offset less than half symbol rate is applied but not limited to a DVB-S system. A target channel is selected to obtain a carrier frequency and a symbol rate for programming a tuner to obtain a digital baseband signal. A down-sampling factor is calculated based on the symbol rate for performing a down-sampling operation to obtain a down-sampling signal that passes through a digital matched filter to generate a filtered spectrum. A moving average and spectrum inversion is applied to detect location of the target channel and find two cross points thereby estimating a coarse carrier frequency offset for compensating the tuner and a coarse symbol rate. A fine carrier frequency offset and a symbol rate estimate are estimated for compensating and acquiring the target channel when the target channel is successfully detected.06-02-2011
20100054377SYSTEMS AND METHODS FOR SPURIOUS SIGNAL REDUCTION IN MULTI-MODE DIGITAL NAVIGATION RECEIVERS - Systems and methods for reducing spurious signals in digital receivers. A system includes a digital navigation receiver having a controllable reference oscillator configured to generate a reference frequency based on a control signal input and a control signal generator in signal communication with the controllable reference oscillator. The control signal generator is configured to generate a waveform that sweeps in frequency such that the reference frequency is based on the waveform. A triangular waveform that sweeps in frequency is used in an example embodiment. A method includes generating a waveform that sweeps in frequency and controlling the reference oscillator based on the waveform.03-04-2010
20090304129OSCILLATING APPARATUS, RECEIVING APPARATUS, AND OSCILLATION CONTROL METHOD - In an oscillating apparatus, a detection unit detects a frequency offset between an input signal and a reference signal. A code generation unit specifies a relationship among a code having a predetermined number of bits, the frequency offset, and a voltage to be applied to a voltage-controlled oscillator by a DAC, in accordance with a frequency offset detection state of the detection unit. The code generation unit also generates a frequency offset correction code having a predetermined number of bits in accordance with the specified relationship. The DAC applies the voltage to the voltage-controlled oscillator, in accordance with the relationship described above and the code generated by the code generation unit. The voltage controlled oscillator outputs an oscillator signal having an oscillation frequency corresponding to the voltage applied by the DAC.12-10-2009
20100054378CENTER FREQUENCY ADJUSTMENT DEVICE AND RELATED METHOD FOR A COMMUNICATIONS RECEIVER - A center frequency adjustment device for a communications receiver includes an A/D converter coupled to an analog filter in the communications receiver for converting an output signal of the analog filter to a digital signal, a carrier frequency offset estimator coupled to the A/D converter for estimating a carrier frequency offset of the communications receiver according to the digital signal, and a control circuit coupled to the analog filter and the carrier frequency offset estimator for adjusting a center frequency of the analog filter according to the carrier frequency offset.03-04-2010
20090028276Method and System for Mobile Receiver Antenna Architecture for U.S. Band Cellular and Broadcasting Services - A method for an antenna architecture that handles US band cellular and broadcast channels may be provided. The method may comprise a multi-network mobile device comprising one or more antennas. The method may further comprise receiving via one or more antennas, and processing at a first radio frequency integrated circuit (RFIC), cellular signals in a 1900 MHz band. The method may further comprise receiving via one or more antennas, and processing at a second RFIC, cellular signals in a 850 MHz band and receiving via one or more antennas, and processing at a third RFIC digital broadcast signals in a UHF broadcast band.01-29-2009
20110069793Method and Apparatus for Estimating Frequency Offset and Timing Offset of One or More Mobile Stations - A method and apparatus for estimating frequency offset and timing offset of a first Mobile Station (MS) in a communication system is provided. The method includes receiving a composite signal at a plurality of receiver antennas of a Base Transceiver Station (BTS). The composite signal includes a first signal transmitted from a first MS and a second signal transmitted from a second MS. The composite signal includes one or more tiles. Each tile includes a plurality of data sub-carriers, a plurality of first pilot sub-carriers, and a plurality of second pilot sub-carriers. A total phase offset of the first MS is estimated based on a complex conjugate product of pilot symbols of the plurality of first pilot sub-carriers. Thereafter, a first phase offset corresponding to the timing offset of the first MS is estimated based on a Power Delay Profile (PDP) of one or more first pilot sub-carriers. Finally, a second phase offset corresponding to the frequency offset of the first MS is determined based on the total phase offset and the first phase offset.03-24-2011
20110075771METHOD AND APPARATUS FOR MITIGATION OF INTERFERENCE - A method of reducing error in transmissions received in a receiver is provided. A transmission containing a synchronization signal is inputted through a first filter to a synchronization correlator, to generate a timing error of the synchronization signal. An amount of delay of the synchronization signal sufficient to reduce the timing error is determined. The transmission is delayed by the amount of delay by being passed through at least a second, variable filter whose delay is determined using a stochastic gradient algorithm. The synchronization correlator may also generate a deviation error of the synchronization signal and determine an amount of deviation correction sufficient to reduce the deviation error as well as generating a frequency error of the synchronization signal and determining an amount of frequency correction sufficient to reduce the frequency error.03-31-2011
20110069792DIGITAL PHASE-LOCKED LOOPS AND FREQUENCY ADJUSTING METHODS THEREOF - A digital phase-locked loop having a phase frequency detector (PFD), a 3-state phase frequency detection converter (3-state PFD converter), a loop filter and a digital voltage-controlled oscillator is provided. The PFD receives an input frequency and a reference frequency and outputs a first signal and a second signal based on the phase difference between the input frequency and the reference frequency. The 3-state PFD converter outputs a 3-state signal according to the first and second signals, wherein the 3-state signal is presented in 1, 0 and −1. The loop filter outputs at least one control bit based on only the 3-state signal. The DCO adjusts the outputted oscillation frequency according to the control bit.03-24-2011
20110150151COMPENSATION FOR DATA DEVIATION CAUSED BY FREQUENCY OFFSET USING TIMING CORRELATION VALUE - A method and circuitry for detecting a frequency offset (Δ) between data at a transmission symbol rate (fTx) transmitted from a transmitter and a reception sampling frequency (fRx) operating in a receiver on the basis of hard decision based on a binary number in the receiver. The receiver uses a converter to make binary hard decisions performs n times oversampling, then obtains a symbol decision value, calculates a timing correlation value for each plurality of partition phases, and calculates a cumulative timing correlation value for a specific period or number of additions. The receiver determines whether its sampling frequency is higher or lower than a correct symbol rate, appropriately shifts a sampling position, and makes reception while maintaining the correct sampling position thereby enables data deviation caused by a frequency offset to be compensated on the fly.06-23-2011
20100098195Systems and methods for frequency offset correction in a digital radio broadcast receiver - Methods and systems for correcting a frequency error in a digital portion of a radio broadcast signal are disclosed. The methods and systems include the steps of receiving a radio broadcast signal having an analog portion and a digital portion, separating the analog portion of the radio broadcast signal and the digital portion of the radio broadcast signal, determining a coarse frequency offset of the analog portion of the radio broadcast signal, generating an error signal for adjusting a frequency of the digital portion of the radio broadcast signal, wherein the error signal is based on the coarse frequency offset of the analog portion of the radio broadcast signal, and adjusting the frequency of the digital portion of the radio broadcast signal with the error signal that is based on the coarse frequency offset of the analog portion of the radio broadcast signal, such that a frequency error in the digital portion of the radio broadcast signal is reduced below a predetermined amount.04-22-2010
20080267325Ultra-wideband transceiver - The processing of information signals is described in an Ultra Wideband (UWB) transceiver. The transceiver has both transmission and receiver paths for processing information signals. In the receiver path, broadcast RF signals are converted to a zero intermediate frequency (IF) signal using a reference signal from a phase-locked loop (PLL) that can selectively provide a reference signal corresponding to the center frequencies of a plurality of signal band groups. The IF signal is then selectively modulated into the baseband signal to be digitized for presentation. In the transmission path, the in-coming digital signals are converted to analog baseband signals and selectively modulated into their own zero IF signals. Using the same PLL of the receiver path, the zero IF signals are modulated into the transmission RF signals directed to the target signal band of the target signal band group.10-30-2008
20080253485BROADCAST RECEIVING APPARATUS AND METHOD FOR RECEIVING BROADCAST SIGNAL - A broadcast receiving apparatus includes: an input unit to which a high frequency signal is input; a conversion unit that converts the high frequency signal into a digital intermediate frequency signal; a differential output unit that differentially outputs the digital intermediate signal converted by the conversion unit; a demodulation unit that demodulates the digital intermediate frequency signal that is differentially output from the differential output unit; and a resonance unit that includes a coil and a capacitor that are serially connected with each other between the differential output unit and the demodulation unit, the resonance unit being configured to pass the digital intermediate frequency signal while attenuating out-of-band component of the digital intermediate frequency signal.10-16-2008
20120148001SEMICONDUCTOR INTEGRATED CIRCUIT AND RECEIVING APPARATUS - A receiving apparatus includes a first circuit to receive a radio wave of a first frequency band from a tuning circuit, a second circuit, including an amplifier to receive a radio wave of a second frequency band lower in frequency than the first frequency band, and a generating circuit to generate a tuning voltage for the tuning circuit in a first state in which the radio wave of the first frequency band is received, and a bias voltage for the amplifier in a second state in which the radio wave of the second frequency band is received. The generating circuit includes a voltage generator to generate and output the tuning voltage and the bias voltage to an output route, and a switching circuit to switch the output route to couple to the amplifier in the second state.06-14-2012
20100166124DIGITAL ARCHITECTURE FOR RADIO-FREQUENCY APPARATUS AND ASSOCIATED METHODS - A radio-frequency (RF) receiver includes a receiver analog circuitry and a receiver digital circuitry. The receiver analog circuitry resides within a first integrated circuit and the receiver digital circuitry resides within a second integrated circuit. The second integrated circuit couples to the first integrated circuit via a one-bit digital interface. The receiver analog circuitry receives an RF signal and processes the received RF signal to generate a digital signal. The receiver analog circuitry provides the digital signal to the receiver digital circuitry. The receiver digital circuitry includes a digital down-converter circuitry that mixes the digital signal with an intermediate frequency (IF) local oscillator (LO) signal to generate a digital down-converted signal. The receiver digital circuitry also includes a digital filter circuitry that filters the digital down-converted signal to generate a filtered digital signal.07-01-2010
20100166122Systems and methods for fast seek and scan functions in a digital radio broadcast receiver - Methods and systems for advancing to another service from a plurality of services in a digital radio broadcast receiver are described. The methods and systems include the steps of receiving an instruction to advance to another service from a man-machine interface of the digital radio broadcast receiver, selecting an entry from a set of entries stored in a memory of the digital radio broadcast receiver responsive to the instruction, wherein each entry identifies a service, and wherein at least some of said services correspond to services identified as receivable, tuning to a first service identified by the selected entry, rendering content received on the first service at the digital radio broadcast receiver, and updating the set of entries stored in the memory of the digital radio broadcast receiver based on at least one criteria.07-01-2010
20100158165PARALLEL AUTOMATIC FREQUENCY OFFSET ESTIMATION METHOD AND APPARATUS - Disclosed is a wireless signal receiving apparatus, and more particularly, disclosed is a parallel automatic frequency offset estimation apparatus and method for tracking a frequency offset in an early stage by calculating, in parallel, frequency offsets of a received signal. The parallel automatic frequency offset estimation apparatus includes a receiving unit to receive a data frame; and a frequency offset estimation unit to calculate, in parallel, frequency and phase deviations at different bit intervals within a particular section of the received data frame, to add together the frequency and phase deviations to obtain a first sum of the frequency and phase deviations, and to add the first sum to a frequency phase deviation calculated for each bit after the particular section in the received data frame to obtain a second sum of the frequency and phase deviations. Accordingly, transmission frequency tracking can be performed at higher speed, compared to the conventional systems in which frequency offset acquisition is carried out in stages. Also, accurate tracking of a transmission frequency is possible in an initial frame.06-24-2010
20090310722TRACKING SYSTEM - The present invention relates to a tracking system comprised in a receiver, which tracking system is operable to track rapid changes in frequency and phase offset. The tracking system comprises a first system operable to perform a pilot-based phase and frequency tracking. The tracking system also comprises a second system operable to perform data-based phase and frequency tracking. The tracking system also comprises a control means connected to said first system and to said second system, which control means is operable to gradually reduce the effect of said first system, i.e. said pilot-based phase and frequency tracking.12-17-2009
20120307947SIGNAL PROCESSING CIRCUIT, WIRELESS COMMUNICATION DEVICE, AND SIGNAL PROCESSING METHOD - An exemplary object is to provide a signal processing circuit, a wireless communication device, and a signal processing method for reducing crosstalk of an adjacent interfering signal in a desired signal. A signal processing circuit 12-06-2012
20090310721Opportunistic intermediate frequency selection for communication receivers - A method of selecting an intermediate frequency (f12-17-2009
20110026650Rapid Sampling Phase Recovery - In a communication receiver, timing recovery circuitry includes a loop filter associated with a timing recovery loop of a first communication device. The first communication device is in communication with a second communication device prior to a temporary power down/power up sequence in the first communication device. The loop filter is configured to: (i) temporarily disable at least a portion of the timing recovery loop after the temporary power down/power up sequence in the first communication device; and (ii) initiate a progression through a set of potential sampling phases to determine a given sampling phase at which the first communication device can recommence communication with the second communication device.02-03-2011
20120002764FREQUENCY CALIBRATION CIRCUIT FOR AUTOMATICALLY CALIBRATING FREQUENCY AND METHOD THEREOF - Generate a series of digital data according to a pair of differential signals received from a low speed universal serial bus. Calibrate coarsely a frequency of an oscillator according to a width of an end-of-packet of the series of digital data. And calibrate finely the frequency of the oscillator according to a width of a SYNC pattern of the series of digital data.01-05-2012
20110064169FILTER COEFFICIENT CONTROL APPARATUS AND METHOD - This invention relates to an apparatus and a method for controlling a filter coefficient. The filter coefficient control apparatus controls a coefficient of a filter of a phase recovering apparatus, and comprises a phase offset obtaining means, for obtaining a phase offset between a carrier and a local oscillation; an autocorrelation calculating means, for calculating an autocorrelation and related statistics of the phase offset; and a filter coefficient determining means, for determining the coefficient of the filter in accordance with the autocorrelation and related statistics.03-17-2011
20100232552SYNCHRONIZATION AND ACQUISITION FOR MOBILE TELEVISION RECEPTION - A method for synchronizing a receiver to a received signal begins by down-converting the received signal to a first baseband signal. A coarse frequency offset (CFO) of the first baseband signal is determined and is applied to the down-converting of the received signal to a second baseband signal. A fine frequency offset (FFO) of the second baseband signal is determined. The receiver is synchronized to the received signal using the CFO and the FFO.09-16-2010
20120063551DIGITAL FREQUENCY LOCKED DELAY LINE - A device includes a signal generator having a delay locked circuit for providing a number of output signals based on an input signal. The output signals have a fixed signal relationship with each other and with the input signal. The signal generator also includes a selector for selecting an enable signal from a range of signals formed by the output signals. The device further includes a transceiver circuit in which the transceiver circuit uses the enable signal for data processing.03-15-2012
20090135968PHASE-ERROR REDUCTION CIRCUITRY FOR AN IQ GENERATOR - Phase-error-reduction circuitry for an IQ generator, wherein the phase-error-reduction circuitry is arranged to receive I and Q input signals from the IQ generator and to produce I and Q output signals, and wherein the phase-error-reduction circuitry is arranged to sample the I and Q input signals to tend to reduce a phase error between the I and Q output signals.05-28-2009
20120300887HARMONIC REJECT RECEIVER ARCHITECTURE AND MIXER - Receiver architectures and methods of processing harmonic rich input signals employing harmonic suppression mixers are disclosed herein. The disclosed receivers, mixers, and methods enable a receiver to achieve the advantages of switching mixers while greatly reducing the mixer response to the undesired harmonics. A harmonic mixer can include a plurality of mixers coupled to an input signal. A plurality of phases of a local oscillator signal can be generated from a single local oscillator output. Each of the phases can be used to drive an input of one of the mixers. The mixer outputs can be combined to generate a frequency converted output that has harmonic rejection.11-29-2012
20120155581IMPLEMENTATION OF A HIGH PERFORMANCE MULTI-CARRIER RECEIVER USING FREQUENCY SELECTIVITY AND DIGITAL COMPENSATION TECHNIQUES - A system has a first branch and a second branch. The system comprises a first intermediate frequency source of the first branch and a first mixer coupled to the first intermediate frequency source. The system has a second intermediate frequency source of the second branch and a second mixer coupled to the second intermediate frequency source. A frequency of the first intermediate frequency source is different than a frequency of the second intermediate frequency source. The system has an amplifier coupled to an input of the first mixer and an input of the second mixer. A first component of an analog to digital converter (“ADC”) is coupled to the first mixer of the first branch. A second component of the ADC is coupled to the second mixer of the second branch.06-21-2012
20120155580BROADBAND PHASE SYNTHESIS NETWORK WITH SELF-HEALING CAPABILITY - A phase synthesis network having self healing capability. The phase synthesis network includes two phase rotators that receive I and Q input LO signals, that receive a digital control signal, and that can adjust a phase and a gain in response to the digital control signal. An output of each of the phase rotators provides a respective output signal to a switch. The switch provides a selected one of the respective output signals for mixing with a predetermined one of the respective output signals. Two mixers mix signals from the phase rotators with an RF signal. Two analog-to-digital converters provide a respective digital signal representative of the output of the mixers. A baseband digital processor generates digital control signals that are provided to the phase rotators. The circuit has an output terminal configured to provide an output signal representative of the RF signal.06-21-2012
20110103529Estimating Frequency Offset Using A Feedback Loop - According to particular embodiments, a signal communicated from a transmitter to a receiver is received. A frequency offset estimate of the signal is determined. The frequency offset estimate indicates a frequency difference between the transmitter and the receiver. The frequency offset estimate is provided as feedback. A next frequency offset is compensated for according to the feedback.05-05-2011
20120128107RECEIVER WITH CONFIGURABLE CLOCK FREQUENCIES - A method includes, in a receiver that operates using multiple clock signals having respective clock frequencies, accepting a request to receive a target channel frequency. In response to the request, a set of preferred clock frequencies is calculated, which when applied by the receiver will cause the receiver to tune to the target channel frequency while satisfying a predefined criterion relating to interference caused by the clock signals. The target channel frequency is received by setting the clock signals to the preferred clock frequencies.05-24-2012
20120128108Method and System for a Sliding Window Phase Estimator for Wideband Code Division Multiple Access (WCDMA) Automatic Frequency Correction - Aspects of a method and system for a sliding window phase estimator for wideband code division multiple access (WCDMA) automatic frequency correction are presented. Aspects of the system may include one or more circuits that enable adjustment of a current demodulation frequency for receiving at least one subsequent symbol based on a computed weighted sum of a plurality of computed frequency error values. Each of the plurality of computed frequency error values may be derived from a current symbol, a corresponding previous symbol, and/or a previous frequency error value. The current symbol may include a current received symbol segment and one or more previously received symbol segments.05-24-2012
20120163516APPARATUS AND METHOD FOR AUTOMATIC FREQUENCY PREDICTION CONTROL - An automatic frequency control apparatus and method are provided. If the number of frequency error measurements is smaller than a reference number for frequency estimation compensation, the automatic frequency control apparatus performs frequency compensation using a frequency error value, and if the number of frequency error measurements is equal to or greater than the reference number for frequency estimation compensation, the automatic frequency control apparatus performs frequency compensation by estimating a frequency value that is to be used until the next frequency control period. Therefore, since frequency errors are accurately corrected in a high-speed mobile environment, an excellent channel environment may be maintained, and accordingly an occurrence frequency of re-transmission may be lowered, resulting in ensuring a high data rate.06-28-2012
20110182387Blind Mechanism for the Joint Estimation of Frequency Offset and Phase Offset for QAM Modulated Signals - A mechanism for jointly correcting carrier phase and carrier frequency errors in a demodulated signal. A computer system may receive samples of a baseband input signal (resulting from QAM demodulation). The computer system may compute values of a cost function J over a grid in a 2D angle-frequency space. A cost function value J(θ,ω) is computed for each point (θ,ω) in the grid by (a) applying a phase adjustment of angle θ and a frequency adjustment of frequency ω to the input signal; (b) performing one or more iterations of the K-means algorithm on the samples of the adjusted signal; (c) generated a sum on each K-means cluster; and (d) adding the sums. The point (θ07-28-2011
20110182386DIGITAL EXCITER HAVING PILOT SIGNAL COMPENSATION - A digital exciter is presented herein for use in RF broadcasting and wherein the exciter employs pilot signal compensation. This includes an input digital circuit for receiving a modulated digital data at an input sample rate for RF broadcasting at a desired RF frequency. The pilot frequency may be displaced from a desired location at the frequency band because of an error in the input sample rate. A digital compensator determines whether the pilot frequency is displaced and provides a digital correction signal in accordance therewith. A digital correction circuit corrects the pilot frequency in accordance with the correction signal.07-28-2011
20090060101METHOD AND APPARATUS FOR CARRIER FREQUENCY OFFSET SYNCHRONIZATION OF ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING RECEIVERS - A carrier frequency offset (CFO) estimation and synchronization method and apparatus of an orthogonal frequency division multiplexing (OFDM) receiver receiving an OFDM modulated signal. The OFDM receiver's CFO synchronization method includes step (a) performing an initial CFO estimation pull-in step using double correlation, step (b) performing a coarse residue CFO estimate acquisition step using independent combination of the double correlation and auto-correlation, and step (c) performing a small residue CFO tracking step by using the double correlation. Aspects of the invention solves the problems in the related art that a CFO tracking range cannot be reliably used in practice when the CFO tracking range is too narrow and a CFO estimation error increases when the CFO tracking range is too wide.03-05-2009
20120170694DISCRETE TIME RECEIVER - Provided is a discrete time receiver having a structure capable of processing various broadband signals. The discrete time receiver uses a discrete time filter having a sampling frequency in a constant range so as to process a signal having an input frequency in a wide range and a wide bandwidth, so that it is possible to reduce current consumption and the area of the discrete time receiver. Since the discrete time receiver is easily integrated with a digital device, it is easy to design a chip using system on chip (SoC).07-05-2012
20090141837METHODS AND APPARATUS FOR RESOVLING FREQUENCY ERRORS DURING TRANSISTION BETWEEN COMMUNICATION NETWORKS - Methods and apparatus for resolving frequency errors in a wireless device transitioning from a first communication network to a second communication network are disclosed. The methods and apparatus effect reception of a first and second channels from the second communication network where the first channel has known characteristics. The first channel is then decoding for a prescribed period and an initial frequency error value is determined based on the decoding of the first channel. A digital frequency rotator is then adjusted based on the initial frequency error value for purposes of decoding the second channel. The second channel is then decoded using the digital frequency rotator as adjusted based on the initial frequency error value, without further calculation of the frequency error.06-04-2009
20090067555FILTER CIRCUIT, RECEIVER USING THE SAME AND FILTERING METHOD - A filter circuit includes a sampler which samples an input signal to generate a first analog signal, an analog-to-digital converter which converts the first analog signal into a first digital signal, a digital filter which extracts a signal component out of a desired band from the first digital signal to generate a second digital signal, a digital-to-analog converter which converts the second digital signal into a second analog signal, a delay device which imparts a signal delay to the first analog signal to supply a third analog signal, the signal delay being equal to a delay time of the second analog signal relative to the first analog signal, and a subtracter which subtracts the second analog signal from the third analog signal to generate an output signal.03-12-2009
20120314820High-Performance Orthogonal Frequency Division Multiplexing Receiver - Devices, methods, and systems for an orthogonal frequency division multiplexing (OFDM) receiver comprising a processor configured to execute a maximum likelihood timing estimator for OFDM symbol timing, a resampling filter for sampling clock frequency offset correcting via a loop filter, where the loop filter may be configured to receive a symbol timing loop error and provide, via a delay accumulator input signals to the resampling filter, and where the resampling filter may be configured to output a resampled signal for demodulating.12-13-2012
20080298517RECEIVING APPARATUS, PROGRAM AND RECEIVING METHOD - A receiving portion for receiving a wireless signal generated on the basis of a baseband signal having either a predetermined frequency band or a baseband signal having any of partial frequency bands; a signal processing portion for generating the baseband signal; a band shifter for shifting the frequency band of the baseband signal by such an amount of shift that the center frequency of at least a specific partial frequency band is in the vicinity of 0 Hz; a filter portion for outputting a partial signal, which is gained by sampling a signal component of the frequency band having a bandwidth of the specific partial frequency band with approximately 0 Hz as the center frequency, from the baseband signal; and a determining portion for determining the frequency band of the baseband signal on the basis of the partial signal.12-04-2008
20080298516INTEGRATED MULTI-SAT LNB AND FREQUENCY TRANSLATION MODULE - Systems and devices for receiving satellite signals are disclosed. A system in accordance with the present invention comprises a plurality of amplifiers, each amplifier in the plurality of amplifiers receiving the signals, a Frequency Translation Module, comprising a plurality of analog-to-digital converters, wherein each amplifier in the plurality of amplifiers is coupled to a separate analog-to-digital converter in the plurality of analog-to-digital converters, wherein the plurality of analog-to-digital converters convert the signals into digital data streams, a digital signal processing section, coupled to the plurality of analog-to-digital converters, wherein the digital signal processing section at least translates the frequency of the digital data streams and filters the digital data streams, a digital-to-analog section, coupled to the digital signal processing section; wherein the digital-to-analog section downconverts the satellite signals to an intermediate frequency band, and a receiver, coupled to the digital-to-analog section, wherein the receiver receives an output of the digital-to-analog section of the module at the intermediate frequency band, the output of the digital to analog section being on a single coaxial cable.12-04-2008
20110002425CARRIER FREQUENCY OFFSET SYNCHRONIZER FOR OFDM RECEIVER AND METHOD - A method of synchronizing a receiver to a received orthogonal frequency division multiplexing (OFDM) signal. The receiver includes a carrier frequency offset synchronizer having a carrier frequency offset detector, a frequency-locked loop having a controller. A transmitted signal having a carrier frequency is received by the receiver. A carrier frequency offset is estimated by comparing the carrier frequency of the transmitted signal and a reference frequency of a locally generated signal of the receiver. A plurality of parameters of the frequency-locked loop is determined to adjust the reference frequency to reduce the carrier frequency offset. Accordingly, the frequency-locked loop achieves frequency tracking of the OFDM signal.01-06-2011
20110002424METHOD OF OPERATING A MULTI-STREAM RECEPTION SCHEME - A method of operating a multi-stream reception scheme, such as DOCSIS (Data Over Cable Service Interface Specifications), comprising at least two receivers (01-06-2011
20120328058Long-Term Drift Mitigation For Radio Frequency Receivers Utilizing A Free-Running Crystal - Embodiments of a receiver for using a first oscillator signal provided by a crystal resonator to support multiple, different functionalities are provided. The receiver comprises a phase-locked loop (PLL) configured to provide a second oscillator signal based on the first oscillator signal provided by the crystal resonator; a first mixer configured to mix a received signal received over a first input path with the second oscillator signal received over a second input path to provide a first frequency-shifted signal; and an automatic frequency controller (AFC) configured to estimate a frequency offset of the second oscillator signal and adjust the PLL to compensate for the frequency offset. The receiver further can include solutions for mitigating potential sources of noise caused by the frequency of the first oscillator signal not being compensated for by the AFC.12-27-2012
20100166123CASCADED LOCAL OSCILLATOR SYNTHESIZER - A representative integrated circuit comprises a clock signal generator that generates a clock signal, a code pattern generator that generates digital pattern data based on the clock signal, and multiple traversal local oscillator synthesizers that are coupled in a cascaded configuration. Each traversal local oscillator synthesizer includes a transversal digital-to-analog conversion (T-DAC) unit that includes a plurality of registers and a unary modulator (Umod) array. The T-DAC provides frequency selection ranges covering wide operational bands based on the digital pattern data and the clock signal.07-01-2010
20130016800METHOD AND APPARATUS FOR PRECISE OPEN LOOP TUNING OF REFERENCE FREQUENCY WITHIN A WIRELESS DEVICE - A communications subsystem for a wireless device for correcting errors in a reference frequency signal. The communications subsystem comprises a frequency generator for generating the reference frequency signal and a closed loop reference frequency correction module that generates a reference frequency adjustment signal for correcting the reference frequency signal when the communications subsystem operates in closed loop mode. The subsystem further includes an open loop frequency correction means that that samples values of the reference frequency adjustment signal during the closed loop mode and generates a frequency correction signal for correcting the reference frequency signal when the communications subsystem operates in a mode other than closed loop mode.01-17-2013
20110158358System for selecting a sample phase based on channel capacity - The present invention provides a system for selecting a sample phase based on channel capacity. A synchronizer calculates a carrier frequency offset, a sample timing offset, a sampling conversion rate and a frame timing, and counts the candidate sample phases. A digital mixer conducts frequency offset compensation to produce a frequency compensated baseband signal. An interpolator conducts interpolation to compensate and produce an interpolated baseband signal. A digital matched filter performs filtering to produce an over-sampled and filtered baseband signal. A buffer stores the over-sampled and filtered baseband signal. A channel estimator estimates and produces channel frequency responses. A sample phase selector calculates channel capacity corresponding to each candidate sample phase, and selects the one with maximum channel capacity. A down-sampler conducts down-sampling operation to produce the final symbol rate based baseband signal. As such, symbol synchronization can be achieved with enhanced performance.06-30-2011
20110158357ANTENNA DIVERSITY SYSTEM WITH FRAME SYNCHRONIZATION - In an embodiment, a tuner circuit includes circuitry to produce a first DSP frame based on a first RF signal and includes an inter-chip receiver circuit coupled to an inter-chip link and configured to receive an inter-chip frame. The inter-chip receiver circuit is configured to detect a start of frame symbol of the inter-chip frame and to extract a DSP offset and data related to a second DSP frame from the inter-chip frame. The tuner circuit further includes a digital signal processor coupled to the circuitry and to the inter-chip receiver circuit. The digital signal processor is to synchronize the first DSP frame with the second DSP frame based on the start of frame symbol and the digital signal processor offset, the digital signal processor configured to perform a selected antenna diversity operation on the first and second DSP frames to produce an output signal.06-30-2011
20080232517Radio communications system, receiver and receiving method - A mobile station obtains information indicating a system band to be employed from a base station before starting a process of identifying a base station ID. In the identification process, the mobile station obtains a cross-correlation value by coherent integration of pilot signals and scrambling codes which may be candidates by using a synchronization signal as a phase reference, in a channel band for synchronization, and obtains a cross-correlation value by non-coherent integration of the pilot signals and the scrambling codes by using a phase difference between sub-carriers in a frequency direction, in the system band other than the channel band for synchronization. Then, the mobile station merges these cross-correlation values, detects a scrambling code from which a maximum cross-correlation value can be obtained, and identifies the base station ID.09-25-2008
20080225997METHOD AND APPARATUS FOR SYNCHRONIZATION FOR MIMO TDS-OFDM SYSTEM - In a TDS-OFDM system, frequency offset estimate provided. A method for estimating a frequency offset comprising the step of correlating a known PN sequence with a received signal.09-18-2008
20080225996DIGITAL BROADCAST SERVICE DISCOVERY CORRELATION - Aspects of the invention are directed to service and channel discovery in a digital broadcast network. A pilot synchronization symbol, which has known characteristics, is included as a first symbol of digital broadcast frames. The pilot symbol, which can be decoded without having to resort to trial and error methods, contains parameters for the rest of the signal. In another aspect of the invention, at least two pilot symbols may be defined and used at the beginning of each frame. The at least two pilot symbols P1 and P2 may enable fast channel search and service discovery within the frame. Signaling may be realized as a combination of L1 and L2 signaling.09-18-2008
20080225995Digital Broadcast Service Discovery Correlation - Aspects of the invention are directed to service and channel discovery in a digital broadcast network. A pilot synchronization symbol, which has known characteristics, is included as a first symbol of digital broadcast frames. The pilot symbol, which can be decoded without having to resort to trial and error methods, contains parameters for the rest of the signal. So, the rest of the signal can be decoded without trial and error methods after the pilot symbol (and any additional synchronization symbols) is decoded. Channels containing digital video broadcast services can be efficiently detected using the known part of the signal. If the fixed known part is not found from the examined signal, then the signal will be considered a non-digital-video-broadcast signal or an empty channel, and the receiver can promptly proceed to a next channel/frequency. In this way, detecting non-digital-video-broadcast and empty channels becomes relatively fast.09-18-2008
20130177111APPARATUS AND METHOD FOR PERFORMING AUTOMATIC FREQUENCY CONTROL - Disclosed are a device and method for automatically controlling frequency. The automatic frequency control device includes a frequency error detection unit configured to obtain a frequency error detection value of a received carrier, a frequency error prediction unit configured to calculate a first frequency error prediction value on the basis of the frequency error detection value when the frequency error detection value satisfies a preset first criterion, and a frequency error compensation unit configured to calculate a second frequency error prediction value by correcting the first frequency error prediction value, and compensate for a frequency of the carrier on the basis of the second frequency error prediction value when a frequency change rate of the received carrier satisfies a preset second criterion. Therefore, overshoot and undershoot effects are minimized, and thus frequency control may be correctly performed.07-11-2013
20110274221METHODS FOR ADJUSTING SYSTEM CLOCK IN TERMS OF OPERATIONAL STATUS OF NON-BASEBAND MODULE, METHODS FOR PERIPHERAL DEVICE CONTROL ADJUSTMENT, AND ELECTRONIC DEVICES USING THE SAME - A method for adjusting a system clock in terms of an operational status of at least one non-baseband module includes: getting first information corresponding to the system clock required by at least one baseband module, wherein the first information comprises a frequency characteristic of the system clock; getting second information corresponding to the at least one non-baseband module, wherein the second information comprises a frequency characteristic of a radio frequency (RF) signal to be received by the non-baseband module; and selectively adjusting a frequency of the system clock by referring to the first information and the second information.11-10-2011
20080205560METHOD AND SYSTEM FOR UTILIZING DIRECT DIGITAL FREQUENCY SYNTHESIS TO PROCESS SIGNALS IN MULTI-BAND APPLICATIONS - Aspects of a method and system for utilizing direct digital frequency synthesis in multi-band applications are provided. A direct digital frequency synthesizer integrated in a multiband wireless receiver chip may be enabled to generate one or more reference signals that may be utilized to down-convert VHF, UHF and L-band signals to baseband signals. The direct digital frequency synthesizer may further generate one or more reference signals, which may be utilized to calibrate one or more circuits that process received VHF, UHF, and L-band signals. In this regard, the signals generated by the direct digital frequency synthesizer may be utilized to calibrate one or more LNAs in a receive processing chain of the chip and/or one or more filters that may be utilized to process baseband signals.08-28-2008
20120275552Method and System for a Reference Signal (RS) Timing Loop for OFDM Symbol Synchronization and Tracking - Aspects of a method and system for a reference signal (RS) timing loop for OFDM symbol synchronization and tracking may include tracking symbol timing in an Orthogonal Frequency Division Multiplexing (OFDM) signal based on at least a reference symbol set. A receiver timing may be adjusted based on at least the symbol timing. The symbol timing may be tracked by generating an output signal as a function of a guard time Δt11-01-2012
20100316172INCOMPRESSIBLE RF RECEIVER - An incompressible receiver for minimizing undesired higher-order nonlinear distortion products includes a first receiver path configured to receive an input signal having at least one non-baseband frequency. A second receiver path is also configured to receive the input signal. The second receiver path includes at least one odd-order nonlinear distortion reference component and at least one even-order nonlinear distortion reference component. The distortion reference components are configured to be in an “on” state or in an “off” state. A combining element is configured to combine input signals from the first and second receiver paths such that the higher-order nonlinear distortion signals are substantially attenuated at an output of the combining element. An incompressible receiver that has an odd-order nonlinear distortion reference generator including a cubic term and at least one additional term of order greater than 3 and an incompressible receiver front end amplifier (IRFEA) are also described.12-16-2010
20120281794Method and System for Implementing a Single Weight Spatial Multiplexing (SM) MIMO System - Certain aspects of the method may comprise generating at least one control signal that may be utilized to control at least a first of a plurality of received spatially multiplexed communication signals. An amplitude and/or phase of the first received spatially multiplexed communication signal may be adjusted via the generated control signal so that the amplitude and/or phase of the first received spatially multiplexed communication signal may be equivalent to an amplitude and/or phase of a second received spatially multiplexed communication signal. The amplitude of the first received spatially multiplexed communication signal is adjusted within the processing path used to process the first received spatially multiplexed communication signal.11-08-2012
20120281793CORDIC Based Complex Tuner with Exact Frequency Resolution - Systems and methods are disclosed that include selecting a sampling frequency and a tuning resolution frequency. These systems and methods may further include determining a wordlength of the phase accumulator, a numeric representation of the phase range, and a reduced representable value of a phase accumulator. In addition, these systems and methods may include operating the phase accumulator, where the phase accumulator creates an output phase accumulator signal. These systems and methods may further includes adjusting the angle of the output phase accumulator signal, where the output phase accumulator signal is adjusted based upon the operation of the phase accumulator, where adjusting the angle of the output phase accumulator signal creates an adjusted output phase accumulator signal and operating a CORDIC module, and where the CORDIC module performs operations upon the output phase accumulator signal based upon the parameters of the phase accumulator.11-08-2012
20110311005Correction Of Frequency Offsets Greater Than The Nyquist Frequency - There is disclosed a method of estimating frequency offset of a received signal in a terminal apparatus operating in a wireless communication system. The method comprises a) determining a phase change between a first and a second reference symbol of the received signal, wherein the time distance t between the first and the second reference symbols is associated with an observation frequency f such that f=1/t; b) determining a preliminary frequency offset Δf based on the determined phase change, wherein the preliminary frequency offset Δf form a frequency offset hypothesis Δf12-22-2011
20110311004FREQUENCY CORRECTION CIRCUIT, FREQUENCY CORRECTION METHOD AND WIRELESS COMMUNICATION EQUIPMENT USING THEM - There is obtained a frequency correction circuit capable of correcting the frequency errors of received signals with high accuracy and preventing the degradation of demodulated signals, while further suppressing an increase in the circuit scale.12-22-2011
20080260076CARRIER FREQUENCY OFFSET ESTIMATION METHOD AND SYSTEM - In one aspect of the invention, a carrier frequency offset (CFO) estimation method to estimate a CFO value of a received signal is provided, and the method comprises: receiving a preamble signal which includes several non-perfect repeat segments; applying an interpolation procedure to interpolate the perfect repeat point of one segment compared with the next segment or the previous segment; acquiring a delay correlation value based on the two perfect repeat signal segments and estimating the CFO value based on the delay correlation value.10-23-2008
20130202070APPLICATIONS OF UNIVERSAL FREQUENCY TRANSLATION - Frequency translation and applications of same are described herein. Such applications include, but are not limited to, frequency down-conversion, frequency up-conversion, enhanced signal reception, unified down-conversion and filtering, and combinations and applications of same.08-08-2013
20120093268COMMUNICATIONS DEVICE WITH ADAPTIVE CLOCK FREQUENCY - The invention provides a communications device which uses a clock circuit for generating a clock signal, the clock circuit comprising a tuneable oscillator.04-19-2012

Patent applications in class Automatic frequency control