Abstract: An apparatus and method to control signal phase in a radio device includes a phase rotator configured to control a phase of a local oscillator. A phase error determination module is configured to determine phase error information based on received in-phase (I) and quadrature (Q) (IQ) signal values. A phase correction module is configured to derive from the received IQ signal values a correction signal and apply the correction signal to the phase rotator in a path of the local oscillator.

Abstract: Provided is a noise eliminating device that includes: a signal calculator that calculates a difference signal between a signal of one channel out of a plurality of signals input from a plurality of channels and a signal of another channel; a variable filter unit that processes and outputs the signals of channels; an adaptive filter unit that operates by receiving a composite signal of the difference signal and another signal as an input signal; and a unit that calculates an error signal between an output signal of the adaptive filter unit and a signal having correlation with the another signal being set as a desired signal. Characteristics of the adaptive filter are changed by using the error signal. Further, characteristics of the variable filter are changed in accordance with a change in the characteristics of the adaptive filter.

Abstract: Methods and systems for conditioning wireline communications to remove intersymbol interference are provided that used adaptive equalization. The method and systems include using a digital finite state machine to control two feedback loops that adjust the gain and power of the input signal relative to a supplied reference. The eye height of the input signal is conditioned by a gain feedback loop so that signal equalization can be performed in a known state. The digital finite state machine allows the loops to be flexibly run in sequence or concurrently. The adaptation functions can be shut off when adequate signal equalization has been achieve, thus saving power.

Abstract: A communications receiver includes a noise analyzer to characterize the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions. The noise analyzer may provide a selection signal indicating the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions to be used by the communications receiver. In an exemplary embodiment, the communications receiver selects at least one set of filter coefficients to compensate for the interference and/or distortion impressed onto a transmitted communications signal in the presence of a particular time-varying interference and/or distortion condition.

Abstract: A method for recovering a quadrature amplitude modulated (QAM) signal is disclosed. The method includes receiving a QAM signal at a demultiplexers, where the QAM signal comprises multiple modulation schemes, splitting the QAM signal into k branches, where k is the number of QAM modulation schemes of the signal, passing the branch having the lowest order QAM modulation scheme to a first equalizer for recovering and tracking polarization and compensating polarization mode dispersion (PMD), updating a tap updating algorithm with a recovery value determined by the first equalizer, and recovering and tracking polarization and compensating PMD for all other branches based on the recovery value.

Abstract: Systems, methods, and other embodiments associated with adaptive low-complexity channel estimation are illustrated. In one embodiment an integrated circuit includes a controller configured to control a switch to select between a plurality of processing paths that each perform channel estimation using a different order of operations to process an orthogonal frequency-division multiplexed (OFDM) signal.

Abstract: Methods and systems are provided for coarse phase estimation for highly-spectrally efficient communications. An example method may include, equalizing, in a receiver, a received inter-symbol correlated (ISC) signal to generate an equalized ISC signal. A phase adjustment signal may be generated based on an ISC feedback signal. The ISC feedback signal may be generated using a sequence estimation process and a non-linearity model. A phase of the equalized ISC signal may be adjusted using the generated phase adjustment signal, to generate a phase adjusted partial response signal. The phase adjustment signal may be generated based on a phase difference between the equalized ISC signal and the partial response feedback signal.

Abstract: Described embodiments include a process and apparatus that takes into account the operating voltage and temperature (VT) variations of a SERDES receiver implemented in an integrated circuit (IC) or system-on-chip (SoC). An analog equalizer (AEQ) adaptation loop and a decision feedback equalizer (DFE) adaptation loop are disabled after the loops have converged or stabilized the parameters of the AEQ and DFE. While the AFE and DFE adaptation loops are disabled, certain monitor coefficients related to signals corrected by the AFE and DFE are adapted and metrics derived therefrom are generated. The metrics are compared to threshold values to check if they have sufficiently changed over time to warrant re-enabling of the AFE and DFE adaptation loops.

Abstract: A system and method are provided for tuning a serial link. The method includes receiving, by a receiver circuit, an offset correction pattern transmitted over a serial link and sampling the received offset correction pattern based on an offset correction parameter to generate a sampled signal. A distribution of the sampled signal is computed and the offset correction parameter is set based on the distribution. The system includes a receiver circuit that is coupled to the serial link and an offset correction unit that is coupled to the receiver circuit. The receiver circuit is configured to receive the offset correction pattern and sample the received offset correction pattern based on the offset correction parameter to generate the sampled signal. The offset correction unit is configured to compute the distribution of the sampled signal and set the offset correction parameter based on the distribution.

Abstract: There is described herein a real-time scheme, implementable in software, hardware, or a combination thereof, to detect a resonating frequency of a structure from a sensed signal and dynamically set the center frequency of an adaptive compensator for effective attenuation of the resonating frequency.

Abstract: Systems and methods are provided for processing a signal using simplified channel statistics. In an example implementation, a channel profile for a multipath channel is estimated by detecting, within a given range, a number of channel taps associated with a channel impulse response, and assigning each of those channel taps a uniform amplitude value corresponding to a constant signal strength. A signal may be received through the multipath channel and filtered based on the estimated channel profile.

Abstract: An interference cancellation method performed by a receiver includes: determining a strong interference code channel among all code channels that carry a received signal, and determining a signal that corresponds to the strong interference code channel to be a strong interference signal, wherein the received signal has been matched filtered. The method further includes obtaining a reconstructed strong interference signal based on the determined strong interference signal and using a system matrix, performing the interference cancellation for the received signal using the reconstructed strong interference signal, to obtain the signal without interference. The strong interference signal can be reconstructed using the system matrix, and the interference cancellation can be performed for the received signal using the reconstructed strong interference signal.

Abstract: A communication device for transmitting beamformed signals using implicit channel sounding is described. The communication device includes a processor and instructions stored in memory. The communication device receives one or more sounding signals and computes a channel estimate based on the one or more sounding signals. Frequency offset compensation is applied to the channel estimate by the communication device. The communication device also computes a precoding matrix based on the channel estimate and transmits a beamformed signal using the precoding matrix. Another communication device for receiving beamformed signals using explicit channel sounding is also described. The communication device includes a processor and instructions stored in memory. The communication device receives one or more sounding signals, computes a channel estimate based on the one or more sounding signals and applies amplitude compensation to the channel estimate.

Abstract: A system, method and memory medium for performing blind equalization. A block {un} of the baseband samples is received. A function J of a vector f is minimized to determine a minimizer fMIN. The function J depends on vector f according to J(f)=?(|yn|2??)2. The summation ? corresponds to a sequence {yn} of equalized samples. The sequence {yn} of equalized samples is related to the block {un} according to a convolution relation {yn}={un}*f. Parameter ? is a current modulus value. The current modulus value ? is updated to equal a ratio of a fourth moment of the sequence {yn} to a second moment of the sequence {yn}. The minimization and parameter update operations are repeated for a series of received blocks of baseband samples. The minimizer fMIN from a last of the repetitions is used to determine final equalized samples.

Abstract: There is provided a transmission device. The transmission device includes: an adapter device (11) including: a first surface having a plurality of first terminals (21) thereon; and a second surface opposite to the first surface and having a plurality of second terminals (22) thereon, wherein a pitch between the adjacent second terminals is different from a pitch between the adjacent first terminals, a plurality of signal lines each electrically connecting a corresponding one of the first terminals and a corresponding one of the second terminals; and a signal compensation device (12) connected to the adapter device through the signal lines and configured to compensate for a transmission loss of a signal path between the corresponding first terminal and the corresponding second terminal such that the transmission loss is set to a given value.

Abstract: A method and apparatus in which a Tap-Weight Computer (TWC) calculates a Tap-Weight Vector (TWV). The TWV is coupled to a register in each of a plurality of adaptive filter modules. Each such adaptive filter module includes several adaptive filters that each include a tapped delay line. The input to the tapped delay line of each such adaptive filter is one of a plurality of potential interfering signals. The TWV controls the weighting of the outputs from the taps off the delay line. The weighted outputs from each tapped delay line are then subtracted from a received signal which potentially includes interference from the potential interfering signals. The TWC is multiplexed to each of the plurality of adaptive filters so that each adaptive filter is loaded with a TWV calculated by the TWC to reduce the amount of interference contributed by a particular potential interfering signal coupled to an input to that particular adaptive filter.

Abstract: A decoding device to decode a main signal code obtained by encoding low-frequency components of an original signal and to output a lowband main signal for output of a main signal, includes: a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, decoding auxiliary information code obtained by encoding auxiliary information, the auxiliary information being for generating, from the lowband main signal, a highband main signal corresponding to high-frequency components of the original signal; decoding residual code obtained by encoding low-frequency components of a residual signal indicating error components produced by encoding of the original signal, and thereby output a lowband residual signal; generating a highband residual signal indicating high-frequency components of the residual signal, based on the lowband residual signal output by the residual decoder and the output auxiliary information; generating an output signal.

Abstract: A binaural decoder for an MPEG surround stream, which decodes an MPEG surround stream into a stereo 3D signal, and a decoding method thereof. The method includes dividing a compressed audio stream and head related transfer function (HRTF) data into subbands, selecting predetermined subbands of the HRTF data divided into subbands and filtering the HRTF data to obtain the selected subbands, decoding the audio stream divided into subbands into a stream of multi-channel audio data with respect to subbands according to spatial additional information, and binaural-synthesizing the HRTF data of the selected subbands with the multi-channel audio data of corresponding subbands.

Abstract: Methods and apparatus are described for processing data in a wireless communication network. Iterative estimation techniques are used to enable tracking of time-varying communication channels. A signal is transmitted over a channel in the network, the signal comprising a sequence of symbols carried on a plurality of sub-carriers. Boot-up estimator estimates, in a time domain, parameters of a model of the channel based on the received signal. A domain converter transforms at least one of the estimated parameters from the time domain to provide at least one transformed parameter in a second domain. An equalizer and decoder determine estimates of symbols from the received signal using the at least one transformed parameter, and tracking estimator updates the estimated model parameters during reception of the signal using at least one estimated symbol.

Abstract: A sparse equalizer system is disclosed. One or more multiple tapped delay lines (e.g., equalizers and/or pre-equalizers) are implemented to service one or more respective channels with which a communication device operates to support communications with at least one other communication device. Adaptive selection of which subsets of taps of the one or more multiple tapped delay lines is made to control those particular taps of which contribute to one or more subsequent slicer inputs. Those taps which are not currently operating to contribute to the slicer input may undergo processing, updating, etc. in parallel with or simultaneously with the processing of a signal to generate the outputs to be provided to the one or more subsequent slicers.

Abstract: A method and system for operating a communication circuit during periods of reduced energy consumption are disclosed. Data may be transmitted over a communication link from a first device to a second device in a low-power state. The data may be used by the second device to update coefficients and/or synchronize the receiver of the second device to a transmitter of the first device, thereby enabling a more efficient or rapid transition from the low-power state to an active state. A transmitter of the first device and a receiver of the second device may be activated before transmission of the data and deactivated after transmission of the data. In this manner, a receiver of the second device may be refreshed to enable a more efficient transition from the low-power state to an active state.

Abstract: Power aware equalization in a serial communications link that includes a transmitter and a receiver, including: determining, by a power aware equalization module, a required signal eye width and a required signal eye height for signals received by the receiver; identifying one or more signal equalizers for signals transmitted over the serial communications link; identifying one or more cumulative equalizer settings that equalize signals transmitted over the serial communications link to conform with the required signal eye width and the required signal eye height for signals received by the receiver; determining power consumption values associated with each of the one or more cumulative equalizer settings; and setting the one or more signal equalizers to configuration settings in dependence upon the power consumption values associated with each of the one or more cumulative equalizer settings.

Abstract: Continuous-time linear equalization of received signals on multiple wire channels while maintaining accurate common mode signal values. Multiwire group signaling using vector signaling codes simultaneously transmits encoded values on multiple wires, requiring multiple receive signals to be sampled simultaneously to retrieve the full transmitted code word. By misaligning transitions on multiple wires, skew introduces a transient common mode signal component that is preserved by using frequency-selective common mode feedback at the receiver to obtain accurate sampling results.

Abstract: Disclosed are an apparatus (equalizer module or receiving apparatus) of a high speed interface system and a high speed interface system, in which the resistance value of a termination resistor in a circuit for high speed interface is adjusted to follow that of a termination resistor of a sink circuit unit, thereby implementing efficient equalization and high speed interface, and a command bus (CBUS) is not built in an equalizer integrated circuit (IC), so that it is possible to simplify the configuration of the high speed interface system and improve the performance and efficiency of the high speed interface system.

Abstract: A pre-distortion method. A signal to be transmitted Tx is pre-distorted to compensate for nonlinearities of a transmitter. The pre-distorted signal is filtered by an EBEE filter and a baseband filter. The EBEE filter has a filter characteristic of that cancels the baseband filter response over the range of frequencies from a first corner frequency of the baseband filter to a frequency of N*fB where N is a highest order of distortion component being cancelled and fB is the bandwidth of the original signal to be transmitted. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: The invention relates to a channel estimating method for an FBMC telecommunication system. The disclosed estimating method uses the signal before it is filtered by the analysis filter bank. According to a first embodiment, the preamble is composed of a repetition in time of an elementary pattern of pilot symbols and the channel estimate is made in the stationary part of the preamble. According to a second embodiment, the preamble is composed of a predetermined pattern of pilot symbols distributed in time and in frequency, and the channel estimate may be made on a typical part of the preamble. The channel thus estimated is used to make an equalisation before the analysis filter bank.

Abstract: An apparatus is disclosed to compensate for non-linear effects resulting from the transmitter, the receiver, and/or the communication channel in a communication system. A receiver of the communication system contains an image cancellation module that compensates for images generated during the modulation and/or demodulation process. The image cancellation module includes a fine carrier correction loop to correct for frequency offsets between the transmitter and receiver. The image cancellation module includes a coarse acquisition mode and a decision directed mode. The decision directed mode allows for a larger signal-to-noise ratio for the receiver when compared against the coarse acquisition mode.

Abstract: Method and filter for filtering a signal, in which the signal is applied to a delay line having a plurality of taps. Respective weighting coefficients of a windowing function are applied to outputs from the plurality of taps to thereby generate a plurality of weighted outputs. The method comprises repeatedly selecting, for output, whichever of the weighted outputs has the highest value.

Abstract: A transmitter and/or receiver for performing frequency domain equalization is provided. A transmitter includes a pilot position determination unit for determining positions for inserting pilots in a frequency domain based on frequency spectrums of data, and a pilot insertion unit for inserting the pilots between the frequency spectrums of the data according to the determined positions for inserting the pilots.

Abstract: A system that incorporates the subject disclosure may include, for example, a process that includes adjusting a filter in electrical communication between an input terminal and a demodulator. The filter is applied to an information bearing signal, e.g., to mitigate interference, received at the input terminal, resulting in a filtered signal. An error signal is received, indicative of errors detected within information obtained by demodulation of a modulated carrier of the filtered signal. A modified filter state is determined in response to the error signal and the filter is adjusted according to the modified filter state, e.g., to improve mitigation of the interference. Other embodiments are disclosed.

Abstract: A method for optimizing the performance of an active HDMI cable. An active cable compensator is provided within the HDMI cable itself. The parameters controlling each of the active components (such as parameters setting gain and frequency distribution) within an individual HDMI cable are set through a programming process. The programming is preferably performed with the cable installed between the actual source and actual sink it will be connecting. The HDMI cable includes an internal controller that governs the equalizers and other active functions. A memory is connected to this controller so that settings may be retained even when power is lost.

Abstract: A phase offset compensator for compensating a phase offset is provided. The phase offset includes a first phase sub-offset and a second phase sub-offset. The phase offset compensator includes a feedback loop comprising a first loop filter, the feedback loop being configured to compensate the first phase sub-offset of the phase offset, and a feed forward loop comprising a second loop filter, the feed forward loop being configured to compensate the second phase sub-offset of the phase offset.

Abstract: In general, the present invention provides methods and apparatuses for exploiting the extra degree of freedom provided by the sensing of the CM signal along with the DM signal at the receiver end of a wireline communication system. According to certain aspects, this extra degree of freedom can be used to cancel alien noises at the receiver in both upstream downstream directions. According to further aspects, a CM channel can be potentially used to exploit the diversity created in the CM channel along with the regular DM channel. This acts as the motivation for employing a diversity receiver scheme at the receiver, especially in downstream communications received at a Customer Premises.

Abstract: A frequency domain-equalizing device receives a digitally modulated single-carrier signal and carries out multipath equalization in a frequency domain. This frequency domain-equalizing device includes a frequency domain-conversion module, a transmission path response-estimation module, an equalization module, an interference decision module, a correction module, and a time-domain conversion module. The interference decision module determines whether at least some portion of a signal is interference and the correction module corrects the signal according to the determination of the interference decision module.

Abstract: A receiver applies a calibration method to compensate for skew between input channels. The receiver skew is estimated by observing the coefficients of an adaptive equalizer which adjusts the coefficients based on time-varying properties of the multi-channel input signal. The receiver skew is compensated by programming the phase of the sampling clocks for the different channels. Furthermore, during real-time operation of the receiver, channel diagnostics is performed to automatically estimate differential group delay and/or other channel characteristics based on the equalizer coefficients using a frequency averaging or polarization averaging approach. Framer information can furthermore be utilized to estimate differential group delay that is an integer multiple of the symbol rate. Additionally, a DSP reset may be performed when substantial signal degradation is detected based on the channel diagnostics information.

Abstract: A variable-precision distributed arithmetic (VPDA) multi-input multi-output (MIMO) equalizer is presented to reduce the size and dynamic power of 112 Gbps dual-polarization quadrature phase-shift-keying (DP-QPSK) coherent optical communication receivers. The VPDA MIMO equalizer compensates for channel dispersion as well as various non-idealities of a time-interleaved successive approximation register (SAR) based analog-to-digital converter (ADC) simultaneously by using a least mean square (LMS) algorithm. As a result, area-hungry analog domain calibration circuits are not required. In addition, the VPDA MIMO equalizer achieves 45% dynamic power reduction over conventional finite impulse response (FIR) equalizers by utilizing the minimum required resolution for the equalization of each dispersed symbol.

Abstract: A receiver may process a received signal to generate a processed received signal. The receiver may generate, during a sequence estimation process, an estimate of a phase error of the processed received signal. The receiver may generate an estimate of a value of a transmitted symbol corresponding to the received signal based on the estimated phase error. The generation of the estimate of the phase error may comprise generation of one or more phase candidate vectors. The generation of the estimate may comprise calculation of a metric based on the one or more phase candidate vectors. The calculation of the metric may comprise phase shifting the processed received signal based on the estimated phase error resulting in a phase-corrected received signal. The calculation of the metric may comprise calculating a Euclidean distance based on the phase-corrected received signal and one or more symbol candidate vectors.

Abstract: A method of generating a hypothesis and estimating a CFO includes receiving a signal including a set of radio frames, dividing each received radio frame of the set into a set of received sub-sequences, dividing, each of reference radio frames from a reference signal stored in the receiver into a set of reference sub-sequences, correlating the set of received sub-sequences with the set of reference sub-sequences to obtain a set of correlation values, generating, a first value set and a second value set of hypothesis based on the correlation values, generating a first and a second hypothesis based on the first value and the second value set, and averaging the first and the second hypothesis to obtain an averaged hypothesis, performing a DFT on the averaged hypothesis to obtain a DFT sequence, determining a peak position of the DFT sequence, and estimating the CFO based on the peak position.

Abstract: There is provided a filter network arrangement comprising a filter network; and one or more correction networks, wherein the one or more correction networks is arranged to substantially equalise the passband gain and group delay of the filter network arrangement. Given an appropriate Q for the one or more correction networks, a polynomial for the one or more correction networks can be found that equalises both the passband gain and group delay and the one or more correction networks can be synthesised from the polynomial.

Abstract: Methods, systems, and devices are described for equalizing data from an optical signal. Samples are filtered with at least one filter to compensate for polarization mode dispersion in an optical path. The filtered samples may be used to determine errors based on a difference between a radius of a recovered symbol and a target radius. A parameter may be assigned to one or more of the errors and properties of the at least one filter may be updated based on the assigned parameters. The parameter may be assigned from a small set of parameters based on at least one threshold value. Outputs generated from the filtered samples may also be assigned a parameter from a different set of parameters. The parameter assigned to the output may be used to update the particular set of taps of the at least one filter from which the output was generated.

Abstract: Embodiments of the present invention provide a variable inter symbol interference generator that generates a data signal having a variable amount of inter symbol interference by passing a data signal through (1) a programmable filter having an adjustable frequency response, and through (2) a fixed filter having a fixed frequency response such as a PCB trace, a length of cable, a discrete filter, or the like. By adjusting the parameters and therefore the insertion gain or loss of the programmable filter, a large range of continuously variable and finely-tunable inter symbol interference amounts can be easily generated.

Abstract: A frequency domain chip-level equalizer is disclosed. The equalizer includes an estimation module configured to generate a frequency domain estimate of an auto-correlation function of a received signal; and an equalization module configured to apply frequency domain equalization to the received signal using the frequency domain estimate of the auto-correlation function to generate frequency domain equalized samples of the received signal. The equalizer further includes an Inverse Fast Fourier Transform (IFFT) module configured to generate time domain equalized samples of the received signal from the frequency domain equalized samples.

Abstract: A method of adjusting a post-cursor tap weight in a transmitter FIR filter in a high-speed digital data transmission system. A receiver, over a forward channel, receives a signal from the transmitter and equalizes the received signal using an adaptive analog equalizer coupled to the forward channel and a decision feedback equalizer (DFE) coupled to the analog equalizer. A gain coefficient used to adjust the peaking by the analog equalizer is adapted using an error signal generated by the DFE. The post-cursor tap weight of the transmitter filter is adjusted up or down based on a comparison of the gain coefficient to a set. of limits. The post-cursor tap weight is transmitted to the transmitter over a reverse channel and then equalizers in the receiver readapt. Alternatively, eye opening data and a DFE tap coefficient are used to determine whether the post-cursor tap weight is adjusted up or down.

Abstract: A transmitter's operation is characterized using components having relatively low cost and low complexity. A device includes comparator(s) that compare a transmitter's analog output to predetermined level(s) to generate count(s) associated with analog output range bin(s). Each of the predetermined levels is associated with a corresponding one of the analog output range bins. A transfer function of the transmitter is generated using the comparison count values associated with the analog output range bin(s). A histogram may be generated from the comparison count values associated with the various analog output range bins. An equalizer is implemented to process data that will be transmitted by the transmitter. The equalizer uses equalizer parameter(s) that are selected based on the characterization of the transmitter (e.g., its transfer function, its histogram, etc.). The equalizer may use default or start up parameters until the transmitter's operation is characterized.

Abstract: A receiving apparatus includes a channel estimating unit that performs channel estimation by using a reception signal and obtains a channel estimation value, a demodulation processing unit that performs demodulation processing by using the channel estimation value and the reception signal, a weight calculating unit that calculates weight for decoding for each of channels by using the channel estimation value, and a decoding unit that performs decoding processing by using the weight and a result of the demodulation processing.

Abstract: A frequency domain chip-level equalizer is disclosed. The equalizer includes an estimation module configured to generate a frequency domain estimate of an auto-correlation function of a received signal; and an equalization module configured to apply frequency domain equalization to the received signal using the frequency domain estimate of the auto-correlation function to generate frequency domain equalized samples of the received signal. The equalizer further includes an Inverse Fast Fourier Transform (IFFT) module configured to generate time domain equalized samples of the received signal from the frequency domain equalized samples.

Abstract: The present technique relates to a reception device and a reception method which can improve equalization performance. An equalization processing unit has a time domain equalization unit which equalizes a received signal in a time domain and a frequency domain equalization unit which is provided in parallel to the time domain equalization unit and which equalizes the received signal in a frequency domain, and performs control of switching between the time domain equalization unit and the frequency domain equalization unit. The present technique can be applied to, for example, equalize a signal of data transmitted by way of single carrier transmission or data transmitted by way of multicarrier transmission.

Abstract: A method includes, by a detector, receiving from a low frequency equalizer a data signal and an error signal, matching a tail portion of the data signal to a tail portion of an extended filter-pattern, and, based upon the error signal at a given location of the data signal and upon the imbalance, producing an output signal indicating whether a long-term residual intersymbol interference of the data signal in the error signal has a positive sign or a negative sign. The tail portion of the extended filter-pattern includes an imbalance between a count of each of the possible values and an unfixed sequence. The data signal includes data points with one of at least two possible values.

Abstract: A SerDes receiver comprising: an input for receiving a signal, the signal having a baud rate; an Analog Finite Impulse Response equalizer (AFIR) for equalizing the received signal, the AFIR comprising: a pre-cursor tap having a pre-cursor coefficient; a cursor tap having a cursor coefficient, the cursor coefficient being constrained to a non-negative value; and a post-cursor tap having a post-cursor coefficient; an adaptation block coupled to the AFIR, the adaptation block configured to adjust the pre-cursor coefficient and the post-cursor coefficient based on the received signal, the adaptation block further being configured to constrain the values of the pre-cursor and post-cursor coefficients to be non-positive.

Abstract: An apparatus for encoding data signals includes a transmitter configured to encode and transmit a data signal over a communication channel, the transmitter including a precoder; a signal shaper configured to adjust the data signal by applying an equalization setting to the data signal, the equalization setting including an amplitude and offset and transmit the adjusted data signal to the precoder; and a processing unit. The processing unit is configured to perform: receiving channel coefficients associated with the communication channel; for each of a plurality of amplitude settings and a plurality of offset settings, calculating whether a modulo amplitude level would occur at a receiver using a modulo operation; selecting the equalization setting from the plurality of amplitude settings and the plurality of offset settings based on the calculation; and transmitting a control signal specifying the equalization setting to the signal shaper.