Abstract: A communications system may include a first communications device that may include a transmitter and a modulator cooperating therewith to modulate a coded waveform using a constant phase modulation (CPM) to generate a non-linear CPM waveform, and generate a linear representation of the non-linear CPM waveform, the linear representation including a plurality of pulses. The transmitter and a modulator may further cooperate to remove at least some of the plurality of pulses to define a modified linear representation of the non-linear CPM waveform, and transmit the modified linear representation of the non-linear CPM waveform. The communications system may further include a second communications device that may include a receiver and a single pulse-matched filter linear demodulator cooperating therewith to demodulate the modified linear representation of the non-linear CPM waveform transmitted from the first communications device.

Abstract: An envelope detector receives an input that is an Amplitude-Modulated (AM) or Amplitude-Shift-Keying (ASK) coded signal. Each channel has a sample switch and a diode that charge an internal sampling capacitor. A hold switch connects the internal sampling capacitor to a summing output capacitor or to a post-processing circuit. A reset switch discharges the internal sampling capacitor after each sample. Two or more channels may be time multiplexed to sample alternate cycles of the input, and then their outputs combined by the summing output capacitor or by the post-processing circuit. The diodes may be reversed to detect the negative envelope rather than the positive envelope. Clocks for the switches may be generated from the input, or may be from a separate clock source. Since the sampling window is open for a whole input cycle, the clock source is insensitive to phase error.

Abstract: An object of the present invention is to provide a receiving apparatus and a receiving method capable of preventing phase rotation of a signal after FFT from occurring on a frequency domain. Further, the receiving apparatus according to the present invention is provided with: a window control unit configured to control a position of an FFT window in which FFT is performed to the time domain signal, and output FFT data corresponding to the FFT window; a signal delaying unit configured to generate, from the time domain signal, a plurality of delay signals with different delay amounts; and a signal switching unit having a switch for outputting by switching between two of the time domain signal and the plurality of delay signals based on a predetermined switch timing, the signal switching unit being configured to output the FFT data including the output signal of the switch.

Abstract: In conventional Backplane Ethernet systems, data is transmitted over two pairs of copper traces in one direction using a PAM-2 scheme and a baud rate of 10.3125 GHz, giving an effective bit rate of 10.3125 Gbps. The rate at which data can be transmitted in Backplane Ethernet systems, while still being reliably received, is typically limited by ISI caused by the dispersive nature of the copper traces, frequency dependent transmission losses caused primarily by skin effect and dielectric loss of the copper traces, and cross-talk from adjacent communication lines. The present invention is directed to systems for overcoming these and other signal impairments to achieve speeds up to, and beyond, twice the conventional 10 Gbps limit associated with Backplane Ethernet systems.

Abstract: A novel and useful multi-antenna receiver that receives, demodulates and decodes a broadcast signal, whose modulation and encoding of time and timing information allow for reliable and power-efficient operation. The multi-antenna receiver of the present invention is adapted to eliminate or substantially reduce the reception nulls that occur in receivers having a single antenna that is placed in a fixed position. Two or more antennas are employed whereby the receiver generates a combined signal based on a combination of the individual antenna signals or selects one of the antenna signals for input to the receiver based on desired criteria such as signal-to-noise-and-interference-ratio (SNIR). This results in greater robustness of the communication link by reducing or eliminating reception nulls and by rejecting interference through the selection of the antenna for which the signal-to-interference ratio is higher.

Abstract: In a communication system including a RFID tag, which has a function to record information and a function to carry out wireless communication with an external device and is capable of transmission with using both FM modulation and AM modulation, and a reader/writer for writing and reading information onto and from the RFID tag via wireless communication, a transmission to transmit information from the RFID tag to the reader/writer is carried out with using one of the FM modulation and the AM modulation at the RFID tag. If the reader/writer fails to decode a signal transmitted with using the one of the FM modulation and the AM modulation, transmission with respect to the information is carried out with using the other of the FM modulation and the AM modulation at the RFID tag. In this manner, reading error of data sent from the RFID tag is prevented.

Abstract: An amplitude/orthogonality error compensator includes: an amplitude corrector configured to perform an amplitude correction on an in-phase component and a quadrature component of an input complex signal based on amplitude error information, and to output a complex signal obtained through the amplitude correction; an orthogonality corrector configured to perform an orthogonality correction on the complex signal, obtained through the amplitude correction, based on orthogonality error information, and to output a complex signal obtained through the orthogonality correction; a filter section configured to allow a predetermined frequency component included in the complex signal obtained through the orthogonality correction to pass through the filter section; an amplitude error detector configured to obtain the amplitude error information based on the complex signal that has passed through the filter section; and an orthogonality error detector configured to obtain the orthogonality error information of the complex

Abstract: A bandwidth that is allocated to a transmitted waveform need not be contiguous in frequency space and a frequency content of the transmitted waveform may vary, as needed, even on a signaling interval by signaling interval basis, in order to accommodate a desired transfer rate, reduce or avoid interference and/or enhance an end user experience. According to embodiments of the invention, a set of frequencies that is used to provide frequency content to elements of a waveform alphabet, used to form the transmitted waveform, is varied thus varying a frequency content of the transmitted waveform. A time span associated with the elements of the waveform alphabet may also be varied. Various transmitter/receiver embodiments are disclosed including direct synthesis transmitter/receiver embodiments.

Abstract: A data receiving circuit that can accurately obtain a data signal corresponding to information data from a high speed high density transmitted signal, and a semiconductor device including the data receiving circuit. The amplitude of a first differential signal corresponding to a level difference between a pair of received differential signals, generated in a first differential stage, is amplified and binalized to obtain a received data signal. A second differential signal corresponding to the level difference between the received differential signals, and a third differential signal which is a phase-inverted signal of the second differential signal are generated in a second differential stage provided separately, and a current corresponding to the second differential signal and a current corresponding to the third differential signal are discharged into the respective ones of the pair of transmission lines, thereby suppressing the amplitudes of the received differential signals.

Abstract: The embodiments provide a multi-stage phase estimation method and apparatus. The apparatus is a multi-stage phase estimation configuration. Each stage of the phase estimation configuration includes metric computation modules. Each of the metric computation modules computing a distance metric and search phase angles according to an input signal and an initial search phase angle or a search phase angle of the former stage phase estimation configuration. The number of the metric computation modules is equal to that of the search phase angles of this stage. A selection module selects the search phase angle corresponding to the minimal distance metric as the phase estimation result output of this stage according to the computation results of all metric computation modules. The average time window length of the former stage phase estimation configuration is larger than that of the subsequent stage phase estimation configuration.

Abstract: A mobile electronic device that includes a circuitry configured to acquire synchronization with a spreading code of an intermediate frequency signal that is obtained by converting a frequency of a received signal from a satellite in a global positioning system into a predetermined intermediate frequency, demodulate a message included in the intermediate frequency signal, output a primary signal to a predetermined signal line, and attach a predetermined header to a secondary signal and output the result to the predetermined signal line, and includes a display unit configured to display data corresponding to the primary signal and the secondary signal, such that the primary signal includes results of measuring one of position, velocity, and time of the mobile electronic device based on the message that is demodulated by the circuitry, and that the secondary signal includes the intermediate frequency signal.

Abstract: A transmitting system, a receiving system, a transmitting method and a receiving method capable of implementing communications with multiple rates are described.

Abstract: A receiver of a multiple-input multiple-output (MIMO) system performs QR decomposition of the channel matrix to enable detection of a transmitted vector in a layered manner. In each layer, a sub-vector of the transmitted vector is estimated. A reactive tabu search is performed if an estimated symbol differs from a nearest symbol in the alphabet by a predetermined value. The receiver may order the entries of the channel matrix prior to QR decomposition to enable estimation in an optimum order. In another embodiment, a receiver performs multiple reactive tabu searches to estimate a transmitted vector. The receiver employs a fixed threshold or a variable threshold for a cost function used in the multiple reactive tabu searches depending on whether the MIMO system is under-determined or not. The techniques enable low bit-error rate (BER) performance in MIMO systems with large number of antennas and when higher-order modulation techniques are used.

Abstract: A modulator, a demodulator and a modulator-demodulator are provided. A modulator includes a first intermediate signal processing path adapted to route a first intermediate signal; a second intermediate signal processing path adapted to route a second intermediate signal; a first amplifier coupled into the first intermediate signal processing path; a second amplifier coupled into the second intermediate signal processing path; and a chopper circuit coupled into the first intermediate signal processing path; wherein the chopper circuit is adapted to process the first intermediate signal in dependence on first baseband data; wherein the first amplifier is adapted to amplify the first intermediate signal processed by the chopper circuit in dependence on second baseband data; and wherein the second amplifier is adapted to amplify the second intermediate signal in dependence on the second baseband data.

Abstract: A method for a QAM receiver to decide a value of a received symbol of an N-point QAM constellation transmission including extracting coordinate values for the received symbol, and using a decision method for deciding the value of the received symbol based on the extracted coordinate values, in which the decision method for the N-point QAM constellation is updated based on a clustering of received symbols. A method for a QAM transmitter to modify an N-point QAM constellation including starting with an initial N-point QAM constellation, measuring a clustering of coordinates of the N-point QAM constellation, shifting coordinates of at least one symbol of the N-point QAM constellation, and producing a modified constellation with shifted coordinates, wherein the shifting is based on data describing a clustering of at least some symbols of the N-point QAM constellation. Related apparatus and methods are also described.

Abstract: A receiver may be operable to receive a QAM-based, inter-symbol correlated (ISC) signal having pilot overhead of 5% at a signal-to-noise ratio (SNR). The receiver may be operable to process the QAM-based, ISC signal to output information at a particular rate with a symbol error rate lower than or equal to 1e?2. The first SNR may be at least 3 dB below a SNR required to achieve the same particular information rate and the same symbol error rate while processing a signal having zero inter-symbol interference.

Abstract: A receiver may be dynamically configurable, during run-time, into a plurality of modes of operation. In a first mode of operation the receiver may demodulate received signals having relative low inter-symbol correlation using a near zero ISI filter and symbol slicing. In a second mode of operation the receiver may demodulate received signals having relatively high inter-symbol correlation using an input filter configured to achieve a desired total partial response and a sequence estimation algorithm.

Abstract: A method includes receiving a symbol modulated with multiple bits according to a signal constellation including multiple constellation points. A soft metric is computed for a given bit in the symbol: A first constellation point closest to the received symbol according to a distance measure is found. A row or column of the constellation points, which is closest to the first constellation point according to the distance measure, and over which a value of the given bit is constant and is opposite to the value of the given bit in the first constellation point, is identified. At least the identified row or column is searched for a second constellation point that is closest to the received symbol according to the distance measure. The soft metric is calculated based on the first and second constellation points. The value of the given bit is reconstructed based on the soft metric.

Abstract: A method and apparatus for providing adaptive bearer configuration for MBMS delivery is disclosed. A first aspect of the present disclosure is a method of operating a wireless infrastructure entity (103) wherein a common radio resource (303) is allocated for receiving a response from at least one mobile station (109). A request message, similar to a request for counting, is broadcast to all mobile stations (109) within a coverage area (105). If at least one mobile station (109) responds to the request, PTM transmission mode will be used for MBMS delivery within the given coverage area (105). If more than one mobile station (109) within the coverage area (105) responds to the request, then all the responses will be over the common radio resource (303). The total number of responses to the request message may be limited by providing a probability factor within the request message.

Abstract: An apparatus and a system, as well as a method and article, may operate to send a selected data type without self-definition information to a receiver if a state capable of interpreting the selected data type has been maintained by the receiver, and to send the selected data type with the self-definition information to the receiver if the state capable of interpreting the selected data type has not been maintained by the receiver.

Abstract: Passive detection of a quadrature amplitude modulated (QAM) signal amid noise is achieved by detection of a spectral component of a detected signal that corresponds to a known QAM symbol rate in, for example, a QAM modulated broadband communication system (BCS). Improved authentication can be provided by simultaneously detecting symbol rate components in two or more QAM bands. No modification of a broadband communication system such as by including a marker signal is required and thus there is no requirement for dedication of a portion of the broadband communication system spectrum or problem of marker signal interference with BCS signals.

Abstract: A communications network (20) comprises a network coding node (24) and a network decoding node (26). A method of operating a communications network (20) comprises, at the network coding node (24), performing multi-domain network coding upon a first signal and a second signal to obtain a network coded signal. The first signal is modulated by a first modulation scheme and the second signal is modulated by a second modulation scheme. At least one of the first signal and the second signal includes information in a phase domain and information in an amplitude domain. The method further comprises transmitting the network coded signal over a link to a receiver (26) and performing multi-domain network decoding of the network coded signal as detected at the receiver (26) to obtain the second signal, the receiver knowing and using the first signal for the multi-domain network decoding.

Abstract: A receiver device, A system and a method for reception of a signal having an amplitude that has been modulated with information, wherein a resistive element is provided that converts an electrical quantity into a physical parameter.

Abstract: A method for sending a data from an electromagnetic radiator by polarization modulation of an electromagnetic wave includes radiating from the radiator first and second electromagnetic waves including first and second polarizations respectively, the first polarization being different than the second polarization. The first and second electromagnetic waves form a third electromagnetic wave having a third polarization different from the first or second polarization. The method includes modulating the third polarization responsive to the data by modulating one or more parts of the third electromagnetic wave. The data is sent in the third polarization. A system for sending a data includes an oscillator adapted to generate an oscillating signal, and a phase shifter coupled to the oscillator and adapted to generate a first phase-shifted oscillating signal having a first phase. The phase shifter is adapted to vary the phase difference across a predefined range in response to the data.

Abstract: This disclosure relates systems and methods for a high bandwidth modulation and transmission of communication signals.

Abstract: A broadcast signal transmitter according to one embodiment of the present invention comprises: an input signal generating unit which generates a first input signal and a second input signal; a MIMO encoder which performs MIMO processing of the first input signal and the second input signal to output a first transmission signal and a second transmission signal; and a first OFDM generator and a second OFDM generator which performs OFDM modulation of the first transmission signal and OFDM modulation of the second transmission signal. The MIMO processing applies a MIMO matrix to the first input signal and the second input signal. The MIMO matrix changes phases using a phase rotation matrix, and adjusts power of the first input signal and second input signal using parameter a, wherein the parameter is set to different values in accordance with the modulation types of the first input signal and second input signal.

Abstract: A communications system receiver incorporates a time-averaged DC component subtracter to subtract a time-averaged DC offset component from a received, processed signal. The time-averaged DC offset is selectably calculated from a moving average or a running average. The selection of the time-averaged DC offset can be done depending on whether the receiver operates in a frequency hop mode or not.

Abstract: Aspects of a method and system for channel estimation in a SM MIMO communication system may comprise receiving a plurality of spatially multiplexed communication signals from a plurality of transmit antennas. A plurality of baseband combined channel estimates based on phase rotation may be generated in response to the received plurality of spatially multiplexed communication signals. An estimate of the channel matrix may be determined based on the baseband combined channel estimates. A plurality of amplitude and phase correction signals may be generated in response to receiving the estimate of the channel matrix. An amplitude and a phase of at least a portion of the received plurality of spatially multiplexed communication signals may be adjusted based on the generated plurality of amplitude and phase correction signals, respectively.

Abstract: A receiver circuit for receiving an input signal (IDD, UDD) comprises a detector circuit (111, 111a, 111b, 111c, 111d, 111e, 111f), which is in the form of a sample-and-hold circuit for determining a reference level of the input signal or in the form of a filter circuit for generating a mean value of levels of the input signal (IDD, UDD). The detector circuit generates, on the output side, a referential signal (RS), which is supplied to comparator circuits (113a, 113b, 113c, 113d, 115a, 115b, 115c, 115d). The comparator circuits (113a, 113b, 113c, 113d, 115a, 115b, 115c, 115d) compare an offset level of the input signal (IDD, UDD) with the referential signal (RS) and generate data signals (DATA, DH, DL). The offset input signals (IDD, UDD) are evaluated relatively in respect of the reference level or the mean value of the levels of the input signal.

Abstract: An amplitude modulation (AM) demodulating circuit applied to a radio frequency identification (RFID) system attenuates carrier signals by a notch filter to increase a signal-to-carrier ratio and to reduce complexity and cost of circuit design. The AM demodulating circuit includes an envelope detector, a notch filter, a low-pass filter, and a comparing circuit. The envelope detector performs envelope detection on an AM signal modulated by a carrier frequency to generate an envelope signal. The notch filter filters the envelope signal to generate a first filtered signal, and a zero point of the notch filter corresponds to the carrier frequency of the AM signal. The low-pass filter filters the first filtered signal to generate a second filtered signal, and the carrier frequency of the AM signal corresponds to a stop band of the low-pass filter. The comparing circuit converts the second filtered signal to a digital signal according to a level value.

Abstract: According to one embodiment, a quadrature error compensating circuit for acquiring an in-phase component signal and a quadrature component signal, includes a first filter, a first multiplier, a first subtractor, a second filter, a correlation calculating circuit. The first multiplier multiplies the in-phase component signal by a control value. The correlation calculating circuit calculates a cross-correlation value between an output of the first filter and an output of the second filter, and uses the cross-correlation value as the control value.

Abstract: A method of detecting a communication mode is provided to rapidly detect which one of near field communication (NFC) protocols includes a communication frame pattern of data provided to a receiving device. The method includes receiving a communication frame pattern of data transmitted from an NFC initiator after synchronizing the communication frame pattern with a predetermined sampling clock. The detection of the communication mode may be done by analyzing a start pattern out of the communication frame pattern. Since a communication mode is rapidly detected and data is automatically received without performing an additional operation to set the communication mode, operation performance of a receiving device is improved.

Abstract: Receiver circuitry for processing a received Very Low Intermediate Frequency signal wherein the receiver circuitry comprises a main processing path. The main processing path comprises mixing circuitry arranged to mix a received VLIF signal with a frequency down conversion signal to produce a main path signal. The receiver circuitry further comprises a direct current cancellation path comprising mixing circuitry arranged to mix a DC element of the received VLIF signal with the frequency down conversion signal to produce a DC cancellation signal. The receiver circuitry still further comprises signal summing circuitry arranged to add the DC cancellation signal in anti-phase with the main path signal.

Abstract: A method and apparatus for transmit signal pulse shaping. Automotive vehicle manufacturers that incorporate electronic components into an automotive vehicle must consider emission requirements masks that can be dependent on particular geographic markets as well as the other electronic components contained within a particular automotive vehicle design. A physical layer device is provided that can be configured to operate in multiple emissions configurations using configurable parameters.

Abstract: A modulator generates a modulation signal from an input signal, and a serial-parallel converter generates a subcarrier modulation signal from the modulation signal. An IFFT unit performs an inverse fast Fourier transformation on the subcarrier modulation signal to generate first data. An operator multiplies respective elements of the first data by amplitude coefficients, and further adds dispersion coefficients to the multiplication result, the amplitude coefficients being real numbers other than 0 defined for the respective elements, at least one of the amplitude coefficients having a value other than 1, the dispersion coefficients being complex numbers defined for the respective components, and at least one of the dispersion coefficients having a value other than 0. Then, data symbols are generated based on a calculation result. A transmitter transmits a transmission frame including the data symbols to another apparatus via an antenna.

Abstract: A receiver that receives an Orthogonal Frequency Division Multiplexing (OFDM) signal obtained by modulating a common packet sequence and data packet sequence. The common packet sequence is made up of packets common to a plurality of streams. The data packet sequence is made up of packets specific to one of the plurality of streams. The receiver sorts the common packet sequence, obtained by demodulating the received OFDM signal, in the time domain, and sorts the data packet sequence, obtained by demodulating the received OFDM signal, in the time domain. The receiver then switches the output for error correction from the one sorting over to the other sorting if, while the one sorting supplies its output to the error correction, the other sorting completes its input of a predetermined unit of information to be processed.

Abstract: The present invention aims to provide a transmission device that, in a communication system using multilevel modulation with 2^n levels (n being an integer greater than or equal to two), limits the run length to a predetermined value or less and guarantees DC balance. The transmission device, which transmits data to which 2^n amplitude modulation has been applied, separates data for transmission into n data sequences; encodes one of the n data sequences to guarantee run length, thereby generating a converted data sequence; generates an intermediate data sequence by either inverting or not inverting a specific data sequence so that, based on candidate data, the next output voltage guarantees DC balance; and applies 2^n amplitude modulation to n-bit symbols each of which has a bit in the intermediate data sequence as a most significant bit and bits in the remaining data sequences, excluding the specific data sequence, as subsequent bits.

Abstract: An ASK demodulator comprises a rectification circuit which receives and rectifies an ASK signal to generate a rectified current; an active load circuit is coupled to the rectification circuit and receives the rectified current and present an impedance which is inversely proportional to at least a part of the rectified current when a frequency of a base band signal meets a preset condition; a comparator is coupled to the rectification circuit and the active load circuit and receives a reference voltage and a voltage generated based on, at least in part, the rectified current and the impedance, and compares the reference voltage and the generated voltage to generate a demodulated signal.

Abstract: An apparatus for providing a data encoding scheme may include an encoder. The encoder may be configured to determine, for a digital input value comprising a particular number of bits, whether more than half of the bits of the digital input value have a high value. The encoder may be further configured to encode the digital input value by inverting each of the bits of the digital input value in response to a determination that more than half of the bits of the digital input value have the high value. Corresponding method and computer program product, and a decoder and decoding method are also provided.

Abstract: To quickly and robustly detect the presence of an incumbent user and rapidly relinquish the spectrum to the incumbent user when necessary, carrier recovery is performed in a receiver of the secondary user's cognitive or software radio prior to performing correlation detection with an upsampled reference signal to correct for large frequency offsets and improve the performance of the correlation detector. To detect a received signal, a pilot value is added to a reference signal. The reference signal is upsampled to a sampling frequency of the received signal. The upsampled reference signal is correlated with a demodulated baseband signal to produce a correlation value. It is then determined whether the received signal is present if the correlation value is greater than a predetermined detection threshold value.

Abstract: One embodiment of the present invention relates to a communication system having a digital to analog converter, a first input, a summation component, a compensation filter, and a compensation unit. The converter is configured to receive a first signal. The first input is configured to receive a phase modulation signal. The compensation filter generates a filtered frequency deviation signal to mitigate frequency distortions, such as those from a digital controlled oscillator. The compensation unit includes one or more inputs and is configured to generate a correction signal according to the filtered frequency deviation signal and the first signal. The correction signal at least partially accounts for estimated distortions of the phase modulation signal from the amplitude modulation path and mitigates frequency induced distortions. The summation component is configured to receive the phase modulation signal and the correction signal and to generate a corrected phase modulation signal as a result.

Abstract: A rail-to-rail comparator including a first comparison unit connected to a first terminal and configured to compare differential input signals to differential reference voltages; a second comparison unit connected to a second terminal and configured to compare the differential input signals to the differential reference voltages; and an output unit configured to be driven in response to a clock signal and to generate a complementary output signal according to comparison results of the first and second comparison units.

Abstract: The present invention relates to a communication system having a digital to analog converter, a first input, a summation component, and a compensation unit. The converter is configured to receive a first. The first input is configured to receive a phase modulation signal. The compensation unit includes one or more inputs and is configured to measure amplitude samples of the first signal at a first of the one or more inputs and to generate a correction signal according to the one or more inputs. The correction signal at least partially accounts for estimated distortions of the phase modulation signal from the amplitude modulation path. The summation component is configured to receive the phase modulation signal and the correction signal and to generate a corrected phase modulation signal as a result.

Abstract: An apparatus for demodulating an Amplitude Shift Keying (ASK) encoded signal is provided. The apparatus comprises a peak detector, a first comparator, a threshold generator, a delay circuit, and a second comparator. The peak detector is configured to detect a peak voltage, and the first comparator is coupled to the peak detector and receives a first threshold voltage. The threshold generator is coupled to the peak detector and is configured to generate a second threshold voltage that is proportional to peak voltage. The delay circuit is coupled to the first comparator, and the second comparator is coupled to the delay circuit and that is coupled to the threshold generator so as to receive the second threshold voltage.

Abstract: Various exemplary embodiments of this disclosure provide parallel to serial conversion apparatuses that includes a bit-swapping circuit that generates bit-swapped parallel data by swapping bits of input parallel data, and a parallel to serial conversion circuit that acquires M1 and M2 bits of the bit-swapped parallel data in a first and a second mode, respectively. The parallel to serial conversion circuit generates serial data by arranging the acquired bits of the bit-swapped parallel data in a first specified order in the first mode and in a second specified order in the second mode The bit-swapping circuit swaps the bits of the input parallel data such that the parallel to serial conversion circuit acquires 1st to M1-th and 1st to M2-th bits of the input parallel data in the first and second modes, respectively, and arranges the acquired bits of the input parallel data in the same order.

Abstract: Demodulation methods and apparatus for a multi-stage SLI demodulator are disclosed. Residual signals from each demodulation stage are modeled as finite sets of unresolved signals and a new metric is introduced for use in search of best candidate symbol estimates. The metric may be evaluated based on a probability distribution function of the residual signals or a probability mass function of the unresolved signals. The metric may also be approximated by the sum of a conventional Euclidean metric and a correction metric. The best candidate symbol estimates generated from each stage of the multi-stage SLI demodulator are summed to form cumulative symbol estimates.

Abstract: A demodulation circuit for an Amplitude Shift Keyed (ASK) modulated signal includes an envelope detector, an alternating voltage amplifier, a differentiator circuit, and a comparator having a hysteresis connected in series. The envelope detector produces an envelope signal from the received ASK signal. The amplifier blocks the DC component of the envelope signal and amplifies AC components of the envelope signal to obtain a steeper slope of the rising and falling edges. The differentiator circuit then processes the transition edges to provide a differentiated signal having positive and negative electrical pulses. The comparator converts the pulses into a binary data stream which corresponds to the transmitted data stream. The combination of the differentiated signal and comparator having a hysteresis enables better stability and sensitivity of the ASK demodulation circuit.

Abstract: A system and method for a radio controlled clock receiver adapted to extract timing and time information from a phase modulated signal. The official time signal is broadcast from a central location using a modified modulation scheme, which adds phase modulation over the legacy amplitude modulation, such as the legacy WWVB pulse width modulated (PWM)/amplitude shift keying (ASK) modulation, thereby allowing for improved performance. The information modulated onto the phase contains a known synchronization sequence having good autocorrelation properties, error-correcting coding for the time information and notifications of daylight-saving-time (DST) transitions that are provided months in advance. The modulation scheme is based on a form of phase modulation, such as binary-phase-shift-keying (BPSK) or phase reversal keying (PRK).

Abstract: A method and apparatus for aligning I- and Q-signals in a quadrature receiver based on an squared signal. A correction is evaluated in an iterative manner by finding an average of the squared signal. The average squared signal may be the received signal, in which case the iterations are applied in a feed forward manner. Alternatively, the average squared signal is the aligned signal in which case the iterations are applied in a feed back manner. The correction may include the evaluation of an normalization or, in the feed back case, this can be implicitly included in the manner in which the iteration is applied. Various parameters to the iteration can be set to accommodate the operating environment of the receiver and characteristics of the received signal.

Abstract: Exemplary embodiments are directed to data and clock recovery in NFC transceivers. A transceiver may include a phase-locked loop configured to recover a clock from a received input signal in a first mode and enable for oversampling of an output signal in a second, different mode.