Abstract: The present invention relates to methods, a user equipment and a radio base station in a communication network, in which a downlink out-of-coverage is detected based on measurements done on a common channel or on the combination of common and dedicated channels. The out-of-coverage is then reported to the network, either using resources proactively assigned to the user equipment, or by transmitting a predetermined pattern of signature sequences assigned to the user equipment.

Abstract: A cerebral oximeter includes a first light source for emitting light in response to a first electrical signal, a second light source for emitting light in response to a second electrical signal, a first photodetector for detecting at least a portion of the light emitted from the first light source, and a second photodetector for detecting at least a portion of the light emitted from the second light source. The cerebral oximeter further includes a pseudonoise (PN) code modulator for modulating the first electrical signal and the second electrical signal using a spreading sequence to occupy an electrical bandwidth greater than necessary to send optical signal pulse amplitude information to a photodetector, and a time gate for filtering a first detection signal from the first photodetector and a second detection signal from the second photodetector based on a desired time-of-arrival.

Abstract: A bandwidth detection device comprises a receiving circuit, for receiving a first plurality of frequency-domain signals on a first subchannel; a filter circuit, coupled to the receiving circuit, for transferring the first plurality of frequency-domain signals to a first plurality of filtered frequency-domain signals according to a filter function; and a processing circuit, coupled to the filter circuit, for comparing the first plurality of frequency-domain signals with the first plurality of filtered frequency-domain signals, to determine whether the first subchannel comprises first transmitted data.

Abstract: A receiver includes multi-user detection (MUD) functionality and a cognitive engine. The receiver may also be coupled to multiple antennas and have analog beamforming capability. The cognitive engine is operative for selecting a beam or beams associated with the multiple antennas to enable successful demodulation by the MUD. The receiver has application in multiple access channels and in other communication scenarios.

Abstract: In some embodiments, a method for operating a light detection and ranging (LiDAR) system in an automobile provides a more accurate range estimate by combining multiple processed waveforms which are weighted according to their signal to noise ratios. At least one waveform is transmitted within a first time period, and reflected of an object. The reflected waveform is received and processed to improve the signal to noise ratio (SNR). The processing produces a higher number of output waveforms, such as through processing convolution. The SNR for each of the output waveforms is determined. An estimated range to the object from each output waveform is determined. The estimated ranges are then weighted according to their SNRs, and combined to provide an final determined range to the object.

Abstract: A receiver includes a channel estimation module, a delay spread module, and a smoothing module. The channel estimation module generates a channel estimate for a channel in frequency domain based on a signal received through the channel in time domain. The delay spread module determines a delay spread of the channel in the time domain. The delay spread is an amount of time after which a channel response drops to less than or equal to a predetermined threshold. The smoothing module smooths the channel estimate by applying a filter with unequal taps in the frequency domain. The taps are based on the delay spread. The filter does not attenuate samples of the channel response within the delay spread in the time domain. The filter attenuates noise outside the delay spread of the channel.

Abstract: A receiver includes multi-user detection (MUD) functionality and a cognitive engine. The receiver may also be coupled to multiple antennas and have analog beamforming capability. The cognitive engine is operative for selecting a beam or beams associated with the multiple antennas to enable successful demodulation by the MUD. The receiver has application in multiple access channels and in other communication scenarios.

Abstract: Methods and apparatus for selecting samples for secondary synchronization signal (SSS) detection are described. Several alternatives are provided for efficient cell identifier detection. In a first alternative, multiple bursts of a signal received from a cell are sampled with non-uniform spacing between sampling intervals to determine a sequence for cell identification. In a second alternative, samples of a first and a second signal received from a stronger cell are cancelled, and a sequence for detecting a weaker cell is determined by reducing effects of the samples of a third signal received from the weaker cell which do not overlap with the primary synchronization signal (PSS) or SSS of the stronger cell. In a third alternative, a sequence for detecting a weaker cell is determined by reducing effects of any sampled bursts that correspond to a high transmission power portion of a signal from a stronger cell.

Abstract: The present invention relates to a method and apparatus, in which a station (STA) which operates in an available channel that is not used by a licensed device, detects a signal (hereinafter, referred to as ‘primary signal’) of the licensed device in a white space band, and operates in the available channel. According to the present description, the station receives white space map (WSM) information which contains available channel identification information from a device having database information; acquires the result of measurement for detecting the presence of the primary signal in a specific band range; and transmits, to another station, the WSM which is updated to contain information on the band in which the primary signal is detected, wherein the updated WSM further contains information which indicates whether each available channel in the updated WSM is based on the database information or based on the result of measurement.

Abstract: In a direct sequence spread-spectrum (DSSS) systems, such as CDMA, information is encoded in symbols using phase shift keying or quadrature amplitude modulation. Further, a transmitter applied a selected time shifted lag to each symbol to convey additional information. A receiver detects both the symbol data and the lag value. The receiver can use a hermetic matched filter matrix to identify the lag.

Abstract: An integrated circuit for facilitating spread spectrum reception of data having a data bit period includes an hypothesis search circuit (120, 210, 220) operable to correlate a pseudorandom code with a signal input based on a received signal to produce correlation results, and a processor circuit (320) operable to coherently integrate the correlation results over plural sample windows (PreD1, PreD2) staggered relative to each other in the coherent integration interval and to non-coherently combine the coherently integrated results corresponding to the plural sample windows (PreD1, PreD2) to produce a received signal output, whereby enhancing performance. Other circuits, receivers and processes are also disclosed.

Abstract: In one embodiment, a method for blindly detecting low density spreading (LDS) active signatures including receiving, by a first node from a second node, a signal and decorrelating the signal in accordance with a signature list to obtain an active signature list. The method also includes decoding the signal in accordance with the active signature list to obtain a decoded signal.

Abstract: A filter enhancer provides greater performance in a passive filter. The passive filter has an input terminal for receiving a signal in a first frequency band and an output terminal for providing a signal in a second frequency band. The filter enhancer includes: (a) a first canceller circuit coupled between input terminal and output terminal, the first canceller circuit including a first finite impulse response (FIR) filter for attenuating signals in the first frequency band; and (b) a control circuit coupled to output terminal and first canceller circuit for providing adaptive coefficients for configuring the first FIR filter. The first FIR filter may be implemented by either a digital FIR filter or an analog FIR filter. The filter enhancer may further include a second canceller circuit coupled between input terminal and output terminal, the second canceller circuit including a second FIR filter for attenuating signals in the second frequency band.

Abstract: Method of detecting interference in a satellite radio-navigation signal determines the temporal position for which the correlation between the signal and a local spreading code offset by the position is maximum, calculating an information item representative of the intercorrelation between a first measurement of the correlation of the signal with a local spreading code at a first temporal position advanced relative to the temporal position of the maximum by a duration greater than the duration of a slot of the spreading code and a second measurement of the correlation of the signal with a local spreading code at a second temporal position delayed relative to the temporal position of the maximum by a duration greater than the duration of a slot of the spreading code, and comparing the item with a detection threshold configured at least as a function of the ratio of the powers of the signal and of the interference.

Abstract: A technique detects the presence of a packet identification sequence in a received sequence of samples received over a communications network. The packet identification sequence, when present and properly detected in a received packet, is used to determine a particular type of the received packet from a plurality of packet types that may be received over the communications network. The technique for detecting the packet identification sequence includes detecting a null sequence in the received packet and a predetermined identification sequence in the packet. Detection of the predetermined sequence uses energy estimates for corresponding windows of received samples.

Abstract: A receiver apparatus includes a propagation channel estimating unit that estimates a propagation channel. The propagation channel estimating unit includes a path detector unit that repeatedly performs a process of detecting paths in the order of increase in a propagation channel goodness of fit. The receiver apparatus that estimates a propagation channel at a high accuracy level with a small amount of calculation operation involved is thus provided.

Abstract: A system for implementing an orthogonal frequency division multiplexing scheme and providing an improved range extension. The system includes a transmitter for transmitting data to a receiver. The transmitter includes a symbol mapper for generating a symbol for each of a plurality of subcarriers and a spreading module for spreading out the symbol on each of the plurality of subcarriers by using a direct sequence spread spectrum. The symbol on each of the plurality of subcarriers is spread by multiplying the symbol by predefined length sequences. The receiver includes a de-spreader module for de-spreading the symbols on each of the plurality of subcarriers. The de-spreader module includes a simple correlator receiver for obtaining maximum detection. The correlator produces an output sequence of a same length as an input sequence and the de-spreader module uses a point of maximum correlation on the output sequence to obtain a recovered symbol.

Abstract: Methods and apparatus are disclosed for receiving a diversity transmitted signal using a Rake or G-Rake receiver in a radio system. Signals are diversity transmitted in a first and second symbol period by two or more antennas. One or more receive antennas receive the diverse transmit signals. Weights are generated to account for the correlation between the channels over which the diverse transmit signals are transmitted in the first and second symbol period and are used to weight the received signals. The weighted signals are then fed to a mutual receiver.

Abstract: An integrated circuit for facilitating spread spectrum reception of data having a data bit period includes an hypothesis search circuit (120, 210, 220) operable to correlate a pseudorandom code with a signal input based on a received signal to produce correlation results, and a processor circuit (320) operable to coherently integrate the correlation results over plural sample windows (PreD1, PreD2) staggered relative to each other in the coherent integration interval and to non-coherently combine the coherently integrated results corresponding to the plural sample windows (PreD1, PreD2) to produce a received signal output, whereby enhancing performance. Other circuits, receivers and processes are also disclosed.

Abstract: The present invention provides a transmission system, including: a transmitter including a transmitter filter; a receiver including a receiver filter; and a communicative coupling between the transmitter and the receiver; wherein the transmitter filter and the receiver filter are matched for noise reduction, and wherein the combined responses of the transmitter filter and the receiver filter satisfy the Nyquist criteria. Optionally, the transmitter filter includes a pulse shaping quasi digital finite impulse response filter. Optionally, the receiver filter includes an inductor-capacitor ladder based filter.

Abstract: An OFDM generation apparatus and methods for generating OFDM transmission signals from OFDM symbols, each including a plurality of OFDM subcarriers, for transmission in a multi-carrier data transmission system, is provided. The provided apparatus and method may use a selected mixing frequency for mixing complex time-domain samples of OFDM symbols from a baseband frequency up to a passband frequency to obtain OFDM transmission signals, wherein the mixing frequency is selected such that common phase rotations of the OFDM subcarriers of OFDM symbols with respect to adjacent OFDM symbols of the OFDM transmission signals are avoided or compensated after the mixing. Additional apparatuses and methods for avoidance or compensation of such common phase rotations are also provided.

Abstract: A mobile device that operates in a wireless communication network is disclosed. The mobile device includes a transceiver that uses a first wireless communication technology, which can be Long Term Evolution (LTE) technology. The mobile device also includes a modem that coupled to the transceiver through a standard interface and uses a second wireless communication technology, which can be CDMA. The modem processes the received signal from the transceiver and processes a transmit signal for the transceiver. A first receiver first processing circuit has a matching filter to compensate for and resampling the received signal from the receiver so that that the received signal from the transceiver is compatible with the modem. A transmitter processing has a filter for resampling and adjusting a processed transmit signal for the transmitter.

Abstract: A method is for decoding a pulse signal modulated through a transmitted reference modulation scheme. The modulated pulse signal may include, repetitively, a reference pulse followed by an information pulse delayed with a delay. The method may include subtracting or adding from the modulated pulse signal, a version of the modulated pulse signal delayed with the delay for obtaining a processed signal, and performing a non-coherent detection on the processed signal.

Abstract: Techniques for use in sampling a signal of a receiver are described. In a sampling determination mode, a signal is sampled at a first sampling period for producing a sample set for each phase of the sampled signal. For each sample set, a correlation process is performed for producing a correlation result. One of the phases associated with an optimal correlation result is identified from the correlation results. In a communication mode, a received signal is sampled at a second sampling period at the phase associated with the optimal correlation result, for recovering user or signaling information from the received signal. The second sampling period is less than the first sampling period.

Abstract: Provided are a method for dynamically acquiring a PN synchronization of a blink signal in a reader according to a channel state when a tag transmits a direct sequence spread spectrum (DSSS) blink signal having a predetermined period and the reader receives the blink signal in a 2.4 GHz RTLS system which complies with an ISO/IEC24730-2 standard, and a method for synchronizing a frame using a preamble.

Abstract: A method for communicating comprises generating at least one generalized Golay code from a concatenation of constituent Golay codes, and spreading at least a portion of a data stream with the at least one generalized Golay code. Generalized Golay codes comprise pseudo-complementary sequences having code lengths that differ from Golay complementary sequences and are characterized by low autocorrelation sidelobes relative to the autocorrelation peak.

Abstract: The present invention includes a method of determining a phase estimate for an input signal having pilot symbols. The method includes receiving a plurality of pilot symbols, and then multiplying two or more pilot symbol slots by corresponding correlator coefficients to correct a phase estimate of the input signal.

Abstract: Techniques for recovering a desired transmission in the presence of interfering transmissions are described. For successive equalization and cancellation (SEC), equalization is performed on a received signal to obtain an equalized signal for a first set of code channels. The first set may include all code channels for one sector, a subset of all code channels for one sector, multiple code channels for multiple sectors, etc. Data detection is then performed on the equalized signal to obtain a detected signal for the first set of code channels. A signal for the first set of code channels is reconstructed based on the detected signal. The reconstructed signal for the first set of code channels is then canceled from the received signal. Equalization, data detection, reconstruction, and cancellation are performed for at least one additional set of code channels in similar manner.

Abstract: A communication method comprises generating a Golay code having a zero-DC level when differentially encoded and continuously rotated. A preamble of a data stream is spread with the Golay code, and the data stream is modulated with continuous phase modulation (CPM), such as constant envelope 2-CPM, before being transmitted. A method for acquiring a received signal having a spread sync field modulated with 2-CPM comprises performing chip-level differential detection of the received signal, correlating the received signal with a Golay sequence; and accumulating the correlator outputs.

Abstract: A transmitter includes a synthesis filter bank to spread a data symbol to a plurality of frequencies by encoding the data symbol on each frequency, apply a common pulse-shaping filter, and apply gains to the frequencies such that a power level of each frequency is less than a noise level of other communication signals within the spectrum. Each frequency is modulated onto a different evenly spaced subcarrier. A demodulator in a receiver converts a radio frequency input to a spread-spectrum signal in a baseband. A matched filter filters the spread-spectrum signal with a common filter having characteristics matched to the synthesis filter bank in the transmitter by filtering each frequency to generate a sequence of narrow pulses. A carrier recovery unit generates control signals responsive to the sequence of narrow pulses suitable for generating a phase-locked loop between the demodulator, the matched filter, and the carrier recovery unit.

Abstract: Provided are a method and apparatus (receiver) of receiving and processing a radio signal in a transmitter-receiver environment. The radio signals are transmitted across a wireless interface using Ultra Wideband (UWB) pulses. A transmitted reference approach is utilized. The radio signal include pairs of UWB pulses with each pair of pulses separated by a fixed time delay. The two pulses are then combined to provide for improved noise immunity.

Abstract: The invention relates to a method in a receiving communication node for performing channel estimation on a signal received over a channel from a transmitting communication node. The receiving and transmitting communication nodes are comprised in a radio communications network.

Abstract: The present invention discloses a method for implementing automatic frequency control, and an apparatus thereof. The method discloses: calculating a correlation value of common pilot symbols in a reception signal of each path and a frequency offset value, calculating a combined frequency offset value according to the frequency offset value of each path, and determining, according to the combined frequency offset value, a frequency offset adjustment value for a voltage controlled oscillator, a frequency offset adjustment value for overall reception signals and a frequency offset adjustment value for the reception signal of each path. The present invention selects a method of small-scope frequency offset estimation, which makes frequency offset estimation more accurate.

Abstract: A surface acoustic wave (SAW) correlator spread-spectrum (SS) receiver is disclosed which utilizes a first demodulation stage with a chip length n and a second demodulation stage with a chip length m to decode a transmitted SS signal having a code length l=n×m which can be very long (e.g. up to 2000 chips or more). The first demodulation stage utilizes a pair of SAW correlators which demodulate the SS signal to generate an appropriate code sequence at an intermediate frequency which can then be fed into the second demodulation stage which can be formed from another SAW correlator, or by a digital correlator. A compound SAW correlator comprising two input transducers and a single output transducer is also disclosed which can be used to form the SAW correlator SS receiver, or for use in processing long code length signals.

Abstract: A multimode communication device with a shared signal path programmable filter and a method for utilizing a shared signal path programmable filter in a multimode communication device. Various aspects of the present invention comprise a first module adapted to receive a first communication signal (e.g., corresponding to a first communication protocol) and a second module adapted to receive a second communication signal (e.g., corresponding to a second communication protocol). A shared filter, communicatively coupled to the first and second modules, may be adapted to filter the first and/or second communication signals in accordance with a plurality of selectable sets of filter response characteristics (e.g., associated with the first and second communication protocols). A filter control module may be adapted to select a set of filter response characteristics from a plurality of such sets and program the shared filter to filter a communication signal in accordance with the selected set.

Abstract: One embodiment of the present invention relates to an analog correlation unit comprising a plurality of parallel correlation components configured to operating according to an advanced switched-capacitor low pass filter principle that increases coding gain of the unit. Each correlation component comprises a sampling stage and a correlation stage. The sampling stage may comprise a switched capacitor configured to sample a received baseband signal to determine a value (e.g., polarity) of the baseband signal. The sampled baseband signal is provided to the correlation stages, which may respectively comprise a plurality of switched integrators configured to selectively receive and integrate the sampled baseband signal over time depending upon values (e.g., polarity) of the correlation code to generate voltage potential values. The analog correlation result is evaluated by a comparison of an adjustable threshold voltage with the difference between the output voltage potential values.

Abstract: A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.

Abstract: A signal processor for GPS or other GNSS radiolocalization systems, includes a RAM pre-correlation buffer which is filled in sync with the code NCO, thus all sample alignment in the buffer is fixed The device further includes an amplitude compressor to limit the size of the buffer memory and is optimized to provide data to the following DFT unit in small bursts that can be processed in real time without the need for intermediate buffers. Thanks to these features the processor limits the amount of fast intermediate memories, is simpler and has lowerpower consumption.

Abstract: A signal acquisition system efficiently acquires a transmitted signal even at very low power. The system may synchronize to a preamble structure in the transmitted signal and, for example, determine timing parameters that locate the preamble with respect to system timing or other clock references. The system is particularly effective at acquiring weak power signals and is also robust against significant noise and other impairments, and therefore improves the ability of a receiving device that incorporates the signal acquisition system to acquire the signal and establish communication with other devices.

Abstract: In a wireless access network, a transmitter provides a pool of sequences having a reduced peak-to-average power ratio. Information to be transmitted is mapped to a selected at least one of the pool of sequences. The selected at least one sequence is transmitted over an orthogonal frequency division multiple access (OFDMA)-based wireless link of the wireless access network.

Abstract: A signal processing apparatus for determining whether a receiving signal is a target signal is provided. The apparatus includes: a sampling device for sampling the receiving signal to generate a plurality of sampled values; a first calculation device, coupled to the sampling device, for generating a plurality of first values according to the sampled values and a plurality of reference values; a second calculation device, coupled to the first calculation device, for grouping the first values into a plurality of value groups, respectively calculating the value groups to generate a plurality of second values and generating a determination value by calculating the second values; and a determination device, coupled to the second calculation device, for determining whether the receiving signal is the target signal by comparing the determination value with a threshold value.

Abstract: A method for receiving modulation signals includes receiving a plurality of multiplexed modulation signals each transmitted from multiple antennas of a communication partner, wherein each modulation signal includes a pilot symbol sequence consisting of plural pilot symbols used for demodulation. Each of the pilot symbol sequences is inserted at the same temporal points in the each modulation signal. The pilot symbol sequences are orthogonal to each other with zero cross correlation among the plurality of modulation signals, each pilot symbol having a non-zero amplitude, the quantity of the plural pilot symbols in each sequence being greater than the quantity of the plurality of transmitted modulation signals.

Abstract: A user equipment and corresponding method detect a frequency division permanent common pilot and include a controller configured to use a sliding correlator with a frequency division phase-shift, an averaging unit configured to average a peak magnitude output of the sliding correlator over a predetermined number of sub-frames for each of possible reference pilot sequence and each sample shift of the sliding correlator, and a maximum peak storing unit configured to store first and second maximum peaks depending on corresponding ratios and a threshold. The user equipment and method thereof also include a pilot sequence index candidate storing unit configured to store a pilot sequence index candidate for each shift of the sliding correlator. The user equipment and method thereof include a selector configured to select the pilot sequence index candidate with a lowest peak ratio to shift the sliding correlator.

Abstract: A receiving system dynamically searches the communications band for transmissions of messages having the same nominal communications parameters, including the use of the same spreading code, but having potentially different specific frequencies and code-phases. The receiver, which is independent of the transmitters, samples the communications band at each code-phase of the spreading code over a span of downconverted transmission frequencies. When a message element is detected at a particular code-phase and frequency, it is forwarded to a demodulator that demodulates the message and sends it to its intended destination. In a preferred embodiment, a progressive Fourier Transform is used to incrementally determine the power level at each successive code-phase at a given frequency, thereby substantially reducing the time required to search for transmissions at each discrete code-phase.

Abstract: The invention includes a method for transmitting and detecting high speed Ultra Wideband pulses across a wireless interface. The transmitter includes a serializer and pulse generator. The receiver comprises a fixed delay line, multiplier, local serializer (with a sequence matching the transmitter), digital delay lines, low noise amplifier and logic fan-out buffer along with an array of D flip-flop pairs. Each flip-flop pair is enabled, at fixed time increments, to detect signals at a precise time; the timing is controlled by the pseudo-random sequence generated by the local serializer. A local tunable oscillator is controlled by detecting the phase change of the incoming signal and applying compensation to maintain the phase alignment and clock synchronization of the receiver to the clock reference of the transmitter. The invention uses a pair of pulses with a fixed delay and then relies on mixing the two to provide better noise immunity.

Abstract: There is provided a radio receiver including: a first matched filter, a second matched filter, a first frame synchronization determining unit and a first phase determining unit. The first matched filter performs matching processing on the basis of N first tap coefficients and sign information of a received digital signal to obtain first output data. The second matched filter performs matching processing on the basis of M (M is a natural number smaller than the N) second tap coefficients, the sign information and amplitude information of the received digital to obtain second output data. The first frame synchronization determining unit determines a first frame synchronization timing of the received digital signal on the basis of the first output data. The first phase determining unit determines a first phase amount of the received digital signal on the basis of the second output data and the first frame synchronization timing.

Abstract: A configurable all-digital coherent demodulator system for spread spectrum digital communications is disclosed herein. The demodulator system includes an extended and long code demodulator (ELCD) coupled to a traffic channel demodulator (TCD) and a parameter estimator (PE). The demodulator also includes a pilot assisted correction device (PACD) that is coupled to the PE and the TCD. The ELCD provides a code-demodulated signal to the TCD and the PE. In turn, the TCD provides a demodulated output data signal to the PE. The PACD corrects the phase error of the demodulated output data based on an error estimate that is fed forward from the PE. Accumulation operations in the ELCD, TCD, and PE are all programmable. Similarly, a phase delay in the PACD is also programmable to provide synchronization with the error estimate from the PE.

Abstract: A method for performing delay locked looping upon a received signal which reduces the asymmetry of auto-correlation function resulting from sampling is provided. The received signal is a spread spectrum code signal, and the method includes: generating a plurality of replica spread spectrum code signals according to an estimated code phase delay and phase spacing, the replica spread spectrum code signals having phases respectively different from the phase of the received signal; calculating a spread spectrum code error statistics signal according to the replica spread spectrum code signals and the received signal; and adjusting the estimated code phase delay according to the spread spectrum code error statistics signal and a phase difference between a sampled point of at least one replica spread spectrum code signal and a corresponding signal transition point.

Abstract: In a communication system adapted to MIMO transmission, a receiver may include a filter to filter signals received from a transmitter through the receiver antennas and having a weight matrix thereof updated by an adaptive algorithm with respect to each substream message symbol from the transmitter, and a code generator to feed back a part of the weight matrix updated by the filter, as an updated STF code, to the transmitter. The transmitter may make the transmission using the updated STF code which is optimized for a current channel state.

Abstract: The present invention includes a method of determining a phase estimate for an input signal having pilot symbols. The method includes receiving a plurality of pilot symbols, and then multiplying two or more pilot symbol slots by corresponding correlator coefficients to correct a phase estimate of the input signal.