Entries |
Document | Title | Date |
20080285684 | Compact Dual Receiver Architecture for Point to Point Radio - A radio frequency receiver comprising a receiver module, an intermediate frequency (“IF”) module, a synthesizer module and a controller module. The receiver module receives a radio frequency signal and provides a baseband in-phase signal and a baseband quadrature signal eliminates a sideband of the in-phase and quadrature signals to create a first and a second signal, downconverts the first and second signal to a first and a second IF signal, and selects one of the first or second IF signals. The IF module receives the first or second IF signal, performs analog-to-digital conversion on the first or second IF signal, and demodulates the digitally converted. If signal The synthesizer module receives a programmable reference signal, downconverts the reference signal to an IF feedback signal, downconverts the reference signal to a baseband feedback signal provides the IF feedback signal to the IF module, and provides the baseband feedback signal to the receiver module. The controller module samples the digitally converted IF signal and provides the programmable reference signal to the synthesizer module to thereby provide a demodulated output signal. | 11-20-2008 |
20080285685 | Apparatus and Method for Generating Soft Bit Metric and M-Ary Qam Receiving System Using the Same - Provided are an apparatus and method for generating a soft bit metric and a multi-level (M-ary) Quadrature Amplitude Modulation (QAM) receiving system using the same. The apparatus includes an analog to digital converter for converting an analog symbol signal of a demodulated I (Inphase) or Q (Quadrature) channel into a digital signal, a sealer for scaling the converted digital signal based on a reference value used for determining a space between symbols, a positive integer converter for calculating a positive integer of the scaled digital I or Q channel symbol signal, a sign determinator for determining a sign of the scaled digital I or Q channel symbol signal, and a bit information converter for converting the scaled digital I or Q channel symbol signal into soft bit metric information per bit on the basis of the calculated positive integer and the determined sign value. | 11-20-2008 |
20080304597 | SYSTEM AND METHOD FOR DECODING AUTOMATIC IDENTIFICATION SYSTEM SIGNALS - Various embodiments are described herein for a system and method of detecting Automatic Identification System (AIS) signals in space and decoding these signals. In one aspect, a system for performing this function is described which includes a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data, and a processing unit configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals, decode the one or more candidate AIS message signals to obtain corresponding message segments and validate the decoded message segments for proper AIS formatting. | 12-11-2008 |
20090016465 | Interference Suppression Method and Apparatus - A composite baseband signal includes a desired signal component modulated according to a first modulation scheme and an interfering signal component modulated according to a second modulation scheme. Information is recovered from the composite signal by applying a phase rotation associated with the second modulation scheme to the composite signal to generate a rotated signal. Based on the rotated signal, a channel model associated with the desired signal component and interference cancelling filter coefficients associated with the interfering signal component are generated. The rotated signal is filtered according to the interference cancelling filter coefficients to suppress the interfering signal component from the rotated signal. The filtered signal is equalized based on branch metrics derived from the channel model and symbol hypotheses rotated in accordance with a difference in phase rotations associated with the first and second modulations to recover information from the desired signal component. | 01-15-2009 |
20090028273 | Variable-frequency circuit with a compensation mechanism - The present invention discloses a variable-frequency circuit with a compensation mechanism, which comprises: a load sensing/decision unit, a frequency-division unit and a level modulation unit. The present invention applies to a power supply having a frequency-division mode. The power supply has a feedback unit generating a feedback signal. The load sensing/decision unit determines the operational mode according to the feedback signal. The frequency-division unit generates a reference frequency signal. The level modulation unit generates a reference level signal. During frequency variation, the level modulation unit generates a compensation current to modulate the reference level signal. Thereby, the PWM unit of the power supply can adjust the working cycle of the power supply according to the reference frequency signal, the reference level signal and the feedback signal. | 01-29-2009 |
20090086851 | Method And System For Quadrature Local Oscillator Generator Utilizing A DDFS For Extremely High Frequencies - Methods and systems for a quadrature local oscillator generator utilizing a DDFS for extremely high frequencies. Aspects of one method may include utilizing the DDFS to generate a first signal that may comprise an in-phase (I) component and a quadrature phase (Q) component. A base signal may be divided to generate a second signal with an in-phase (I) component and a quadrature phase (Q) component. The I and Q components of the first and second signals may be mixed by a plurality of mixers, and the outputs of the mixers may be combined to generate an in-phase component of a local oscillator signal and a quadrature phase component of the local oscillator signal. The frequency of the local oscillator signal may be controlled by inverting or not inverting outputs of one or more of the mixers. | 04-02-2009 |
20090086852 | DATA RECEIVER DEVICE AND DATA TRANSMISSION/RECEPTION SYSTEM - The data receiver device includes: a bit phase synchronizing circuit ( | 04-02-2009 |
20090116586 | DIRECT CONVERSION RECEIVER AND METHOD FOR CORRECTING PHASE IMBALANCE THEREIN - A direct conversion receiver and a method for correcting phase imbalance therein is disclosed. An input signal is applied to an in-phase channel and a quadrature channel of the receiver. The input signal is processed by the direct conversion receiver to obtain an in-phase zero intermediate frequency (IF) signal in the in-phase channel and a quadrature zero-IF signal in the quadrature channel. The in-phase zero-IF signal and the quadrature zero-IF signal are filtered to obtain a fixed band signal. A phase imbalance correction value is obtained for the fixed-band quadrature zero-IF signal as a function of the frequency of the fixed-band in-phase zero-IF signal and the fixed-band quadrature zero-IF signal. The in-phase zero-IF signal and the quadrature zero-IF signal are sampled and the phase imbalance correction value is applied using an interpolation to the sampled quadrature zero-IF signal or to the sampled in-phase zero-IF signal to correct the phase imbalance in the direct conversion receiver. | 05-07-2009 |
20090129508 | QUADRATURE ALIGNMENT IN COMMUNICATIONS RECEIVERS - The present invention, generally speaking, takes advantage of the properties of quadrature signals to achieve precise quadrature alignment in a simple fashion. In particular, the expectation of the product of quadrature signals is zero. In accordance with the teachings of the invention, a phase error detection network therefore operates by multiplying the received quadrature signals and low-pass filtering the product to produce an error signal. When the signals are in precise quadrature relationship, the error signal will be zero. Real-time feedback control may be used to drive the error to zero. In accordance with another aspect of the invention, a variable phase shift network is achieved using a dual delay line. The difference in delay between the two delay lines is adjusted in response to the error signal to obtain precise quadrature alignment. The principles of the invention may be applied in connection with traditional mixer architectures or with switch-mode (e.g., “aliased undersampling”) architectures. | 05-21-2009 |
20090154601 | COMMUNICATIONS DEVICE AND RELATED METHOD WITH IMPROVED ACQUISITION ESTIMATES OF FREQUENCY OFFSET AND PHASE ERROR - A repeated preamble bit or symbol pattern such as for a binary phase shift keyed (BPSK) communications signal is received within a modem. An initial frequency offset and phase error estimate is generated by processing a Fast Fourier Transform (FFT) that detects the repeated preamble pattern for a block of samples within the communications signal. Two halves of the block of samples are correlated with a plurality of different BPSK shifted sequences to obtain a symbol timing alignment based on the shifted sequence providing the maximum correlation value. A frequency offset estimate is iteratively updated an N number of times using the shifted sequence providing the maximum correlation value to refine an acquisition estimate of the frequency offset and phase error of the received communications signal. | 06-18-2009 |
20090154602 | COMMUNICATIONS DEVICE AND RELATED METHOD WITH REDUCED FALSE DETECTS DURING START OF MESSAGE BIT CORRELATION - A communications device includes a signal input for receiving signals such as a binary phase shift keyed (BPSK) communications signal having a repeated preamble bit or symbol pattern. A modem processes the communications signal and includes a demodulator and processor that generates an initial frequency offset estimate and phase error estimate by processing a Fast Fourier Transform (FFT) that detects the repeated preamble pattern for a block of samples within the communications signal, correlates within a start of message correlator to search for a start of message sequence and correlates different phases of the repeated preamble pattern within training correlators for reducing false detections of the start of message. Radio circuitry is operative with the modem for processing communications data obtained from the communications signal. | 06-18-2009 |
20090154603 | Weather band radio having digital frequency control - In one embodiment, the present invention includes a digital mixer to receive and digitally mix incoming weather band radio data with a control signal, a digital demodulator to demodulate the data to obtain a demodulated signal, and a digital feedback loop coupled between the demodulator and the digital mixer. The digital feedback loop includes a loop filter to receive the demodulated signal and to generate a filtered output and a fine tune controller to receive the filtered output and a frequency control signal and to generate the control signal based on them. In this way, audible artifacts caused by a frequency step change occurring in an analog front end to which the digital circuitry is coupled can be reduced or removed. | 06-18-2009 |
20090161797 | SATELLITE DETECTION OF AUTOMATIC IDENTIFICATION SYSTEM SIGNALS - A system and method of detecting Automatic Identification System (AIS) signals in space and decoding these signals. In one aspect, a system for performing this function is described which includes a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data, and a processor configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals, decollide and decode the one or more candidate AIS message signals to obtain corresponding message segments and validate the decoded message segments for proper AIS formatting. | 06-25-2009 |
20090175384 | MULTI-SYMBOL NONCOHERENT CPM DETECTOR HAVING A TRELLIS STRUCTURE AND A LOCK DETECTOR THEREFOR - Multi-symbol non-coherent continuous phase modulation (CPM) detectors having a trellis structure, methods of continuous phase detection using a trellis structure, and trellis-based lock detectors and methods for digitally modulated signals are described. The continuous phase modulation detector includes receiver, observation, memory, and adjustment portions. The receiver has a trellis structure and is adapted for receiving digitally modulated signals having a generally continuous phase. The observation portion is adapted for performing multi-symbol observations on received digitally modulated signals and the memory is adapted for storing historic observation data corresponding to multi-symbol observations performed by the observation portion. The adjustment portion is adapted for selectively adjusting the receiver in accordance with stored historic observation data. A trellis-based lock detector computes a global survivor for consecutive time indexes as a maximum cumulative branch metric corresponding to a given time index for consecutive branches of the trellis structure. | 07-09-2009 |
20090207942 | Embedded Multimedia System and Related Digital Audio Broadcasting Demodulator - An embedded multimedia system for playing analog and digital audio broadcasting signals includes an antenna for receiving analog and digital audio broadcasting signals, an audio output device for outputting sound, an analog demodulator for demodulating analog audio broadcasting signals for the audio output device, and a digital demodulator for conducting a signal connection between the antenna and the analog demodulator, or transforming digital audio broadcasting signals into analog audio broadcasting signals for the analog demodulator. | 08-20-2009 |
20090285335 | Adaptive Digital Filter, FM Receiver, Signal Processing Method, and Program - A complex signal in which one of two signals that have been generated from a single real signal and that have phases that are shifted 90° with respect to each other is a real part and the other signal is an imaginary part is applied as input to an input terminal. A filter unit generates an output signal that is a complex signal by means of a convolution operation of the input signal, and a filter coefficient that is a real signal and supplies this output signal to an output terminal. A coefficient control unit made up from a common unit and separate units updates the filter coefficients such that the value of the envelope of the output signal approaches a target signal. | 11-19-2009 |
20100034318 | Binary continuous phase modulation (CPM) data demodulation receiver - A communications receiver receives a received continuous phase modulation (CPM) signal having an original modulation index of h and includes a filter, a continuous phase reconstructor using phase unwrapping, and a modulation index scaler for generating a reconstructed CPM signal having a scaled modulation index H from the received CPM signal having a small modulation index h, with the scaled modulation index H preferably being greater than the original modulation index h, so that, the transmitted CPM signal occupies a narrow bandwidth, yet, during reception, the reconstructed CPM signal with the high modulation index H can be reliably data demodulated for improved performance with reduced demodulation complexity. | 02-11-2010 |
20100054367 | RECEIVER I/Q GROUP DELAY MISMATCH CORRECTION - A device for minimizing group delay mismatch in a quadrature receiver ( | 03-04-2010 |
20100067618 | D-PSK Demodulation Based On Correlation Angle Distribution - An apparatus and method is described that provides optimal D-PSK demodulation based on the distribution of phase differences between successive D-PSK symbols. A plurality of D-PSK data symbols are received, and each symbol is characterized by a real component and an imaginary component. An angle of correlation between any two successive symbols is calculated. A variance of correlation angles is obtained by using data symbols or pilot symbols, if available. The probability of the correlation angle being each of possible phase difference according the D-PSK constellation is then determined. From the probabilities of the particular correlation angle, a probability of each input bit being a “0” or “1” is determined. | 03-18-2010 |
20100091908 | APPARATUS AND METHOD FOR ANALYZING IDENTIFICATION SIGNAL BASED ON PARTIAL CORRELATION - Provided is an apparatus and method for analyzing identification (ID) signals by converting radio frequency (RF) signals which are transmitted with an ID signal added thereto by a transmitting part, e.g., a plurality of transmitters or repeaters, into signals of a desired band; creating ID signals that are identical to the ID signals added to the RF signals; calculating correlation values between the converted signals and the created ID signals based on partial correlation; and extracting channel profile of multi-path signals caused by a channel between the transmitting part and the ID signal analyzing apparatus from the correlation value. The technology of the present research is applied to broadcasting and communication. | 04-15-2010 |
20100104045 | IQ MISMATCH CORRECTION CIRCUIT - An IQ mismatch correction circuit comprises: a correction circuit which performs a correction process to I-phase and Q-phase input signals by using one pair of first- or higher-order digital filters; two or more control circuits which independently generate two or more control variables to derive two or more coefficients of transfer functions of the digital filters; and one or more pairs of analyzing filters which change frequency characteristics of the corrected I-phase and Q-phase output signals so that the frequency characteristics is different from those of the original signals. The first control circuit measures a temporally averaged IQ phase mismatch state between the I-phase and Q-phase output signals. The second control circuit measures a temporally averaged IQ phase mismatch state between output signals on I-phase and Q-phase sides of one pair of analyzing filters. These states are fed back to the digital filters as first and second control variables, respectively. | 04-29-2010 |
20100119012 | PROGRAMMABLE WIDE BAND DIGITAL RECEIVER/TRANSMITTER - A receiver uses a wideband intermediate frequency (IF) in the analog domain and performs low IF down-conversion in the digital domain, using low-power, high-speed, high resolution analog-to-digital converters. The receiver can be integrated into an integrated circuit as one of several receivers. Such an integrated circuit may include multiple transmitters using adaptive non-linear modeling pre-distortion. The non-linear modeling may include memory. Imbalance in intermediate frequency in-phase and quadrature signals may be corrected in the digital domains. DC offsets in the intermediate signal may be corrected in both analog and digital domains. In one instance, the receiver provides a feedback receiver for the adaptive pre-distorter in a transmitter on the integrated circuit. | 05-13-2010 |
20100119013 | APPARATUS AND METHOD FOR REMOVING COMMON PHASE ERROR IN A DVB-T/H RECEIVER - A receiver is a Digital Video Broadcasting-Terrestrial/Handheld (DVB-T/H) receiver. The DVB-T/H receiver comprises a fast fourier transform (FFT) operative on a signal for providing an FFT output signal comprising a number of samples; a spectrum shifter for reordering the samples in the FFT output signal to provide a spectrum shifted signal; and a phase corrector for estimating a phase error from the FFT output signal and for correcting a phase of the spectrum shifted signal in accordance with the estimated phase error. | 05-13-2010 |
20100135437 | SIGNAL RECEIVING APPARATUS AND METHOD FOR WIRELESS COMMUNICATION SYSTEM USING MULTIPLE ANTENNAS - Provided are a receiving apparatus and method for a wireless communication system using multiple antennas. A receiving method for a wireless communication system using multiple paths, the receiving method comprising: receiving signals through a predetermined number of multiple paths; sensing a carrier according to saturation state degrees of the signals, and providing saturation state information; calculating automatic gain components of the received signals by using the received signals and the saturation state information of the received signals; and performing a noise matching process to amplify noises on the predetermined multiple paths according to the automatic gain components during a predetermined period. | 06-03-2010 |
20100142650 | Apparatus and Method for Adaptive Rotation Angle Control, Wireless Apparatus, and Computer Program - An adaptive rotation angle control apparatus of this invention includes a communication quality approximating equation storage portion which stores a communication quality approximating equation including as variables reception quality information, amplitude fluctuation information, and a rotation angle; a computation portion which substitutes into the communication quality approximating equation the reception quality information and amplitude fluctuation information of the input information, and a rotation angle, and calculates the value of the communication quality approximating equation; and an adaptive control portion which provides a rotation angle to the computation portion, receives from the computation portion communication quality information, which is the value of the communication quality approximating equation calculated using the rotation angle provided, and determines the optimum rotation angle based on the received communication quality information. | 06-10-2010 |
20100150271 | MODULATED CLOCK, AN IC INCLUDING THE MODULATED CLOCK AND A METHOD OF PROVIDING A MODULATED CLOCK SIGNAL FOR POWER CONTROL - A modulated clock, a method of providing a modulated clock signal, an integrated circuit including a modulated clock and a library of cells including a modulated clock. In one embodiment, the modulated clock includes (1) a clock controller configured to generate a digital control stream and (2) clock logic circuitry having a first input configured to receive a clock signal and a second input configured to receive the digital control stream. The clock logic circuitry is configured to provide a modulated clock signal in response to the clock signal and the digital control stream, wherein the modulated clock signal has an effective frequency that differs from the first frequency. | 06-17-2010 |
20100183095 | RECEPTION SYSTEM FOR SUMMATION OF PHASED ANTENNA SIGNALS - A diversity antenna system and method comprising a plurality of antennas, a plurality of switches and a plurality of phase shifters, wherein the switches and the antennas are selectively opened and closed or switched on an off to achieve equiphasing. This system separates the noise signal from the useful signal in order to achieve a proper determination of the different phases. In addition there is a receiver which is configured to receive the output of the diversity system. The logic control unit is configured to perform particular steps or algorithms in order to achieve equiphasing of the received signals. | 07-22-2010 |
20100183096 | EFFICIENT MULTI-SYMBOL DEINTERLEAVER - Embodiments disclosed herein address the need in the art for an efficient multi-symbol deinterleaver. In one aspect, a plurality of memory banks are deployed to receive and simultaneously store a plurality of values, such as soft decision values determined from a modulation constellation, in accordance with a storing pattern. In another aspect, the storing pattern comprises a plurality of cycles, a selected subset of the plurality of memory banks and an address offset for use in determining the address for storing into the respective memory banks indicated for each cycle. In yet another aspect, the stored values may be accessed in order with a sequentially increasing index, such as an address. Various other aspects are also presented. These aspects have the benefit of allowing multiple symbol values to be deinterleaved in an efficient manner, thus meeting computation time constraints, and conserving power. | 07-22-2010 |
20100195771 | RECEIVER AND RECEIVING SYSTEM - When the first switching circuit outputs the output signal of the first selection filter, the receiver switches the output signal of the second switching circuit to the output signal of the delay compensator, and when the first switching circuit outputs the output signal of the second selection filter, the receiver switches the output signal of the second switching circuit to the output signal of the third selection filter. | 08-05-2010 |
20100202566 | System and method for improved spur reduction in direct RF receiver architectures - Improved spur reduction architectures that improve linearity in direct radio frequency (RF) receiver architectures. Non-uniform sampling in the form of sampling clock phase (or frequency) modulation is used to induce phase (or frequency) modulation on signals that are being received from a given Nyquist zone. At the output of the ADC (analog-to-digital converter), the signals are de-modulated to remove the induced modulation based on the Nyquist zone that is being received. The de-modulation process results in non-desired spurious artifacts (interfering leakage signals and ADC spurs) being spread in the frequency domain. Strong spurious artifacts may be removed after measuring the induced modulation and de-modulating. For the case of weak spurious artifacts, the de-modulation for the desired Nyquist zone spread these signals in the frequency domain. Induced modulation on signals may also provide a dithering effect on the ADC. | 08-12-2010 |
20100202567 | REAL-TIME DIGITAL QUADRATURE DEMODULATION METHOD AND DEVICE FOR ULTRASONIC IMAGING SYSTEM - A real-time digital quadrature demodulation method and device for the ultrasonic imaging system are disclosed in this invention. In addition to a multiplying step and a filtering step, the method further comprises a sine and cosine table generating step for generating the sine and cosine table in real time, and a filter parameter generating step for generating corresponding filter parameters in real time to filter signals from the multipliers. The device comprises two multipliers, two filters, a sine and cosine table generating module, a filter parameter generating module, and two parameter memories. The real-time digital quadrature demodulation method and device for the ultrasonic imaging system according to the invention are capable of effectively saving the storage resource, and are easily controllable. | 08-12-2010 |
20100239050 | METHOD AND SYSTEM FOR SIGNAL PHASE VARIATION DETECTION IN COMMUNICATION SYSTEMS - Aspects of a method and system for signal phase variation detection in communication systems are presented. Aspects of the system may enable detection of phase change between a current received symbol, and one or more previous received symbols. Based on the phase change a channel estimation filter bandwidth may be selected for despreading and/or descrambling one or more subsequent received symbols. In addition, a decision may be made as to whether the subsequent received symbols are to be received based on a closed loop system, or based on an open loop system. | 09-23-2010 |
20100266067 | COMPENSATOR UNIT AND COMPENSATION METHOD FOR I/Q IMBALANCE ERRORS - A compensator unit compensates frequency-dependent imbalance between a sampled in-phase and a sampled quadrature phase signal. The compensator unit includes a delay channel ( | 10-21-2010 |
20100303173 | CIRCUIT FOR DEMODULATING A PHASE MODULATED SIGNAL - A demodulator is provided for demodulating a phase-modulated data signal. The demodulator includes a phase frequency detector to output a voltage representing a phase difference between a received phase-modulated data signal and a reference clock signal. The voltage is input to first and second phase change detectors, which are provided to measure the phase difference of the phase-modulated data signal during first and second time periods, respectively. | 12-02-2010 |
20100310012 | METHODS AND APPARATUSES FOR ADAPTIVE CLOCK RECONSTRUCTION AND DECODING IN AUDIO FREQUENCY COMMUNICATION - The invention relates to methods for adaptive clock reconstruction and decoding in audio frequency. The method includes the steps of: receiving a modulated signal, wherein the modulated signal is modulated by RC-FSK (Return to Carrier Frequency Shifting Keying); performing a spectrum analysis to the modulated signal to obtain a plurality of frequency envelopes; storing the frequency envelopes; searching the peak values of the frequency envelopes and the time points corresponding to the peak values to modify an estimated period; and generating a clock period for the RC-FSK demodulation and a clock phase for the RC-FSK demodulation according to the estimated period. | 12-09-2010 |
20100310013 | SIGNAL RECEIVING APPARATUS, METHOD, PROGRAM AND SYSTEM - A signal receiving apparatus includes: an acquisition section configured to acquire an Orthogonal Frequency Division Multiplexing signal resulting from combination of a plurality of signals transmitted by a plurality of signal transmitting apparatus by adoption of an Orthogonal Frequency Division Multiplexing method; and a demodulation section configured to carry out partial processing of processing to demodulate the Orthogonal Frequency Division Multiplexing signal acquired by the acquisition section by making use of either first pilot signals or second pilot signals where the first pilot signals are pilot signals extracted from the Orthogonal Frequency Division Multiplexing signal acquired by the acquisition section as signals having the same phase for all the signal transmitting apparatus, and the second pilot signals are pilot signals extracted from the Orthogonal Frequency Division Multiplexing signal acquired by the acquisition section as signals having different phases depending on the signal transmitting apparatus. | 12-09-2010 |
20100329392 | Apparatus and Method for IQ Imbalance Calibration in a Receiver - A method and apparatus is disclosed to compensate for an in-phase/quadrature phase (I/Q) imbalance in a communications receiver. The communications receiver may utilize information gained from observing one or more observational interferers to adjust one or more sequence parameters, such as gain and/or phase to provide some examples. The one or more observational interferers including one or more images outside of a desired frequency band of interest. The communications receiver provides one or more sequence parameter values to allow for real-time adjustment of the sequence parameters to compensate for the I/Q imbalances. | 12-30-2010 |
20110064166 | SYSTEM AND METHOD FOR PERFORMING BLIND IQ-IMBALANCE ESTIMATION AND COMPENSATION - An IQ-imbalance of a complex receiver can be corrected by compensating the in-phase signal component and the quadrature-phase signal component produced by the complex receiver for an IQ-imbalance estimated by analyzing the in-phase signal component and the quadrature-phase signal component. A carrier signal can be received at the complex receiver. An in-phase signal component and a quadrature-phase signal component can be generated from the carrier signal. The generated in-phase signal component and the generated quadrature-phase signal component can be analyzed to estimate an IQ-imbalance. Based on the estimated IQ-imbalance, the in-phase signal component and quadrature-phase signal component can be compensated to correct the IQ-imbalance. | 03-17-2011 |
20110090991 | METHOD AND APPARATUS FOR PHASE REFERENCE TRACKING OF DIGITAL PHASE MODULATED SIGNALS IN THE RECEIVER - The present invention discloses a method and apparatus to provide, effectively and robustly, a phase reference in phase-domain for digital phase-modulated signals. Not only the first-order but also higher order PLLs are delineated for robust and fast tracking of frequency errors and time-varying frequency errors between the transmitter and the receiver. This invention can be applied to any phase-modulated signal such as PSK, DPSK, π/4-DPSK, and CPM. The decoders with this invention can achieve close to the performance of coherent detection. | 04-21-2011 |
20110158352 | APPARATUS AND METHOD OF MULTI-STAGE HIGH BIT PER SYMBOL ANALOG DEMODULATION - A multi-stage demodulation circuit receives a given communication signal modulated by a superposition of at least a first modulation scheme and a second modulation scheme, the circuit having a first demodulation stage that demodulates the received communication signal according to the first demodulation scheme, and generates one or more bits representing the first modulation state of the signal. An intermediate demodulation circuit removes the first modulation from the received communication signal to generate an intermediate demodulation signal having only the second modulation. A second demodulation stage demodulates the intermediate demodulation signal according to the second demodulation scheme and generates one or more additional bits representing the second modulation state of the given communication signal. Optionally, another demodulation stage removes the first modulation and the second modulation from the given communication signal, detects a third modulation and generates additional bits representing the third modulation state. | 06-30-2011 |
20110158353 | ORTHOGONALITY DETECTOR, AND QUADRATURE DEMODULATOR AND SAMPLING QUADRATURE DEMODULATOR USING DETECTOR THEREOF - To detect phase mismatches between in-phase and quadrature signals of a quadrature demodulator. The phase mismatches can be detected using the signals obtained by removing high frequency components of output of a multiplier by a low pass filter, the output being the product of the in-phase signals of which low frequency components are removed by a first high pass filter by the quadrature signals of which low frequency components are removed by a second high pass filter. | 06-30-2011 |
20110268229 | SYSTEM AND METHOD FOR DECODING AUTOMATIC IDENTIFICATION SYSTEM SIGNALS - Various embodiments are described herein for a system and method of detecting Automatic Identification System (AIS) signals in space and decoding these signals. In one aspect, a system for performing this function is described which includes a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data, and a processing unit configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals, decode the one or more candidate AIS message signals to obtain corresponding message segments and validate the decoded message segments for proper AIS formatting. | 11-03-2011 |
20120027130 | INTERFERENCE-WEIGHTED COMMUNICATION SIGNAL PROCESSING SYSTEMS AND METHODS - A level of interference affecting signal components of received communication signals is estimated and used to weight the signal components. The signal components in a each of a number of groups of signal components are weighted based on respective interference estimates to thereby adjust signal components for coloured interference, which may vary significantly between different groups of signal components. Each group of signal components may include a single component or components within a relatively narrow sub-band of the communication signals, such as a coherence bandwidth of an Orthogonal Frequency Division Multiplexing (OFDM) signal. | 02-02-2012 |
20120183101 | TRANSMISSION METHOD, TRANSMISSION APPARATUS, AND RECEPTION APPARATUS - A transmission method for transmitting modulation signals of a plurality of channels to the same frequency band from a plurality of antennas. At the time when a symbol used for demodulation is inserted in a channel, in another channel symbol, the same phase and quadrature signals in the in-phase-quadrature plane are made to be zero signals. Thus, a plurality of modulation signals are multiplexed and transmitted and the transmitted multiplexed modulation signals are demultiplexed and demodulated at a reception apparatus, thereby improving the data transmission rate. | 07-19-2012 |
20120236969 | MIMO RECEIVER AND METHOD FOR RECEIVING SPATIALLY-MULTIPLEXED OFDM SIGNALS - In a multiple-input multiple-output (MIMO) system, multiple receive antennas produce a received signal vector, Y, which includes an element for each of the receive antennas. In an embodiment of a de-mapping method performed within a MIMO receiver, a quadrature phase shift keying (QPSK) search is performed within a search space that includes the full constellation of symbol points. Based on the results of the QPSK search, the search space is reduced to fewer than all of the quadrants, and the received signal vector data is scaled and transformed to the reduced search space. A lower-level QPSK search is performed, and the process is repeated until the modulation order is reduced to a QPSK constellation. Hard or soft decisions corresponding to the search results may then be passed to a decoder. | 09-20-2012 |
20120275546 | MULTIPLE SYMBOL NONCOHERENT SOFT OUTPUT DETECTOR - Multiple symbol noncoherent soft output detectors in accordance with embodiments of the invention are disclosed. In a number of embodiments, the multiple symbol noncoherent soft output detector uses soft metrics based on the Log Likelihood Ratio (LLR) of each symbol to provide information concerning the reliability of each detected symbol. One embodiment of the invention includes a receiver configured to receive and sample a phase modulated input signal, and a multiple symbol noncoherent soft output detector configured to receive the sampled input signal and to generate a soft metric indicative of the reliability of a detected symbol based upon observations over multiple symbols. | 11-01-2012 |
20120307943 | RECEIVER CIRCUIT AND RECEIVER APPARATUS - Ano signal period detecting unit ( | 12-06-2012 |
20130083869 | Receiver with Asynchronous and Synchronous Demodulator - A receiver circuit includes an asynchronous demodulator having a demodulator input to receive a first signal and a demodulator output configured to provide a demodulated signal. The receiver circuit further includes a circuit, a multiplexer, and a synchronous demodulator. The modulator circuit includes a modulator input coupled to the demodulator output and includes a modulator output. The modulator re-modulates the demodulated signal to produce a second signal and provides the second signal to the modulator output. The multiplexer includes a first input to receive the first signal, a second input coupled to the modulator output to receive the second signal, a control input to a receive a select signal, and a multiplexer output. The synchronous demodulator includes an input coupled to the multiplexer output and an output to provide a demodulated output signal corresponding to a selected one of the first signal and the second signal. | 04-04-2013 |
20130142286 | WIRELESS COMMUNICATIONS DEVICE HAVING WAVEFORM BANKS WITH FREQUENCY OFFSET AND RELATED METHODS - A wireless communications device includes a receiver, and a demodulator coupled downstream from the receiver and configured to use a continuous phase modulation (CPM) waveform to non-coherently demodulate a received signal. The demodulator is configured to generate waveform banks, each waveform bank having a respective different frequency offset associated therewith, determine a correlation output metric for each waveform bank, select a waveform bank for demodulating the received signal based upon the correlation output metrics of the waveform banks, and demodulate the received signal using the selected waveform bank and the associated frequency offset. | 06-06-2013 |
20130202062 | COLLISION DETECTION USING A MULTIPLE SYMBOL NONCOHERENT SOFT OUTPUT DETECTOR - Systems and methods for detecting collisions in radio frequency tags in accordance with embodiments of the invention are disclosed. In one embodiment, a receiver system includes a receiver configured to receive and sample a phase modulated input signal, and a multiple symbol noncoherent soft output detector configured to receive the sampled input signal and to generate a soft metric indicative of the reliability of a detected symbol based upon observations over multiple symbols, a collision detector configured to calculate a decision metric from a set of soft metrics generated by the multiple symbol noncoherent soft output detector and detect a collision when the decision metric satisfies a predetermined criterion. | 08-08-2013 |
20130216005 | Blind Mechanism for Demodulating Offset QPSK Signals in the Presence of Carrier Phase Error - A computer-implemented system and method for blind demodulation of an offset QPSK input signal, involving repeatedly performing a set of operations, including: (a) applying a phase correction to the input signal based on an estimate of a carrier phase offset of the input signal to obtain a first modified signal; (b) shifting a quadrature component of the first modified signal by half a symbol period relative to an inphase component to obtain a second modified signal; (c) extracting a first sequence of symbols from the second modified signal, where the extraction includes estimating a symbol timing offset from the second modified signal; (d) performing hard-decision demodulation on the first sequence of symbols to obtain a second sequence of reference symbols; (e) computing a phase difference between the first sequence of symbols and second sequence of reference symbols; and (f) updating the carrier phase offset estimate using the phase difference. | 08-22-2013 |
20130279633 | DIGITAL RECEIVER - A receiver and method is provided for sigma-delta converting an RF signal to a digital signal and downconverting to a digital baseband signal. The RF signal is split into N phases, as can be accomplished using a sample and hold circuit, and each phase is digitized, as can be accomplished using an analog-to-digital (A/D) sigma-delta converter. Polyphase decimation techniques and demodulation are applied to the phased signals to generate a demodulated digital signal. The demodulated digital signal is further downconverted to the appropriate baseband signal. | 10-24-2013 |
20130287147 | Maximizing the Viterbi Winning Path Metric to Estimate Carrier Phase Offset in Continuous Phase Modulated Signals - A system and method for estimating carrier frequency offset Δf and carrier phase offset φ | 10-31-2013 |
20140003555 | PHASE COMPENSATION RECEIVER | 01-02-2014 |
20140029700 | MULTI-TAP IQ IMBALANCE ESTIMATION AND CORRECTION CIRCUIT AND METHOD | 01-30-2014 |
20140169502 | RECEIVER AND METHOD OF RECEIVING - A receiver receives payload data from a downstream signal, and includes a filter to receive the downstream signal, and including signalling data identifying downstream resources for the payload data, and an analogue to digital converter to receive the downstream signal from the filter and to convert it into a sampled digital form. A demodulator demodulates the digital form of the downstream signal to recover the payload data and the signalling data. The signalling data includes a mode switch signal to indicate an active mode or a sleep mode for the receiver. A controller detects the mode switch signal to control the analogue to digital converter to switch sampling rates in response thereto, and to control the filter to switch frequency bands. The frequency bands perform anti-alias filtering for respective sampling rates. | 06-19-2014 |
20140177758 | TIMING RECOVERY APPARATUS AND METHOD - A timing recovery apparatus for compensating a sampling frequency offset of an input signal is provided. The timing recovery apparatus includes a timing error corrector configured to generate an output signal according to the input signal and a calibration signal, a gain controller configured to adjust at least one of a signal edge low-frequency error component and a signal edge high-frequency error component of the output signal and accordingly generate an adjusted signal, a timing error detector configured to generate an error signal according to the adjusted signal, and a calibration signal generator coupled to the timing error detector and the timing error corrector, for generating the calibration signal according to the error signal and outputting the calibration signal to the timing error corrector to compensate the sampling frequency offset of the input signal. | 06-26-2014 |
20140192933 | DEMODULATOR FOR FREQUENCY-SHIFT KEYED SIGNALS BY USING THE GOERTZEL ALGORITHM - Exemplary embodiments relates to a demodulator for frequency-shift keyed signals by using the Goertzel algorithm according to the general recursive calculating rule, where | 07-10-2014 |
20140254722 | Digital Receiver - A receiver and method is provided for sigma-delta converting an RF signal to a digital signal and downconverting to a digital baseband signal. The RF signal is split into N phases, as can be accomplished using a sample and hold circuit, and each phase is digitized, as can be accomplished using an analog-to-digital (A/D) sigma-delta converter. Polyphase decimation techniques and demodulation are applied to the phased signals to generate a demodulated digital signal. The demodulated digital signal is further downconverted to the appropriate baseband signal. | 09-11-2014 |
20140355720 | WIDEBAND FM DEMODULATION BY INJECTION-LOCKED DIVISION OF FREQUENCY DEVIATION - A novel and useful wideband FM demodulator operating across an 8 GHz IF bandwidth for application in low-power, wideband heterodyne receivers. The demodulator includes an n-stage ring oscillator that is injection locked to a wideband input signal. Locking to the input frequency, it divides the FM deviation by n, thereby facilitating as well as reducing the energy required for wideband demodulation. The quadrature-phased output of the ring oscillator is auto correlated using a low-power folded CMOS mixer capable of detecting FM up to 400 Mb/s over a 2-10 GHz IF frequency range. | 12-04-2014 |
20150365267 | APPARATUS AND METHOD FOR ESTIMATING SYMBOL TIMING OFFSET - Systems and methods for estimating symbol timing offset in wireless communication networks are described herein. In one example, the method comprises converting a received signal into digital samples and decoding symbols from the digital samples based on estimation of symbol timing offsets (STO), cyclic prefix (CP) correlation peaks and CP correlation confidence levels. The method further comprises decoding frames by processing the decoded symbols, and obtaining data from the decoded frames, wherein the data is to be forwarded to applications of the communication unit. | 12-17-2015 |
20160119068 | VEHICLE AND METHOD FOR CONTROLLING THE SAME - A vehicle and a method for controlling the same are provided. In particular, linking information of a broadcast signal having been output during a turn-off mode is transmitted to a DAB receiver upon receiving a turn-on signal. The vehicle includes a Digital Audio Broadcasting (DAB) receiver that is configured to receive a first DAB signal that corresponds to a selected first broadcast signal. In addition, a speaker outputs the first broadcast signal based on the received first DAB signal or a first frequency-modulation (FM) signal corresponding to the first broadcast signal. In response to receiving a turn-on signal, a controller transmits linking information of the first broadcast signal from among linking information of a plurality of broadcast signals to the DAB receiver to output the first broadcast signal output during a turn-off mode. | 04-28-2016 |
20160149734 | APPARATUS AND METHOD FOR SWITCHING BETWEEN RECEIVERS IN COMMUNICATION SYSTEM - An apparatus for switching between receivers according to a characteristic of a received signal in a communication system includes a radio frequency unit that modulates at least two signals received from transmission devices, and a Channel Impulse Response (CIR) shape comparison unit that determines characteristics of the modulated signals by using a CIR and selects a receiver according to the determined characteristics of the modulated signals. | 05-26-2016 |