Abstract: A method for signal reconstruction, the method may include obtaining, an input digital signal that is a digital representation of an received optical signal, wherein the received optical signal represents a transmitted optical signal that was transmitted by a coherent transmitter and over a channel to a coherent optical receiver; wherein a phase difference between the transmitted optical signal and the received optical signal is unknown; and generating a hybrid estimation, wherein the hybrid estimation represents a magnitude of the transmitted optical signal and a phase of the received optical signal.

Abstract: A method for signal reconstruction, the method may include obtaining, an input digital signal that is a digital representation of an received optical signal, wherein the received optical signal represents a transmitted optical signal that was transmitted by a coherent transmitter and over a channel to a coherent optical receiver; wherein a phase difference between the transmitted optical signal and the received optical signal is unknown; and generating a hybrid estimation, wherein the hybrid estimation represents a magnitude of the transmitted optical signal and a phase of the received optical signal.

Abstract: A rate Detection Apparatus (RDA) includes a power spectral density (PSD) estimator and a rate selector. The PSD estimator is configured to receive samples of a signal, and to estimate a PSD of the signal. The rate selector is configured to identify a transmission rate of the signal responsively to the estimated PSD.

Abstract: A rate Detection Apparatus (RDA) includes a power spectral density (PSD) estimator and a rate selector. The PSD estimator is configured to receive samples of a signal, and to estimate a PSD of the signal. The rate selector is configured to identify a transmission rate of the signal responsively to the estimated PSD.

Abstract: A system for digitally equalizing a data channel with heavily ISI-induced signals received after passing a data communication channel using a combination of a linear equalizer and a nonlinear equalizer, which comprises an ADC, for sampling a received signal and converting it to a digital form; a Linear Equalizer for pre-processing said received signal, said Linear Equalizer is adapted to pre-process a first group consisting of echoes/channel taps of the induced ISI, which are not equalized by said nonlinear equalizer, by eliminating the echoes/channel taps of said first group; pre-process a second group consisting of the combination of the entire echoes/channel taps of the induced ISI, by eliminating the echoes/channel taps of said second group; and a nonlinear equalizer for receiving the signals preprocessed by said Linear Equalizer and for further processing said preprocessed signals and eliminating the echoes/channel taps of the induced ISI to be equalized by said nonlinear equalizer, thereby compensating

Abstract: A method for performing blind channel estimation for an MLSE receiver in a communication channel, according to which Initial Metrics Determination Procedure (IMDP) is performed using joint channel and data estimation in a decision directed mode. This is done by generating a bank of initial metrics that assures convergence, based on initial coarse histograms estimation, representing the channel and selecting a first metrics set M from the predefined bank. Then an iterative decoding procedure is activated during which, a plurality of decision-directed adaptation learning loops are carried out to perform an iterative histograms estimation procedure for finely tuning the channel estimation. Data is decoded during each iteration, based on a previous estimation of the channel during the previous iteration. If convergence is achieved, ISI optimization that maximizes the amount of ISI that is compensated by the MLSE is performed.

Abstract: A method for estimating the phase of a modulated complex optical signal, according to which, the phase of the signal is isolated and the complex amplitude of the signal is digitized by a block of P samples. An adaptive filter minimizes phase-error between the phase of the received symbol and the phase of a sample, rotated by a phase correction factor, by iteratively performing a Block-Wise Phase LMS estimation on the samples using a step size parameter. During each iteration, the resulting correction factor consists of the sum of the estimated errors multiplied by this parameter, and the correction factor of previous iteration, which is updated, until obtaining the final correction factor from the last iteration. The samples constituting the received signal are recovered by adding the most updated correction factor to the phase of each sample and performing a decision regarding the phase of each sample.

Abstract: The present invention is directed to a MIMO equalization system and method, optimized for baud rate clock recovery in coherent symbol-spaced DP-QPSK Metro systems. According to this method, the Mueller & Muller timing function is extended to cope with controlled ISI induced signals, while decoupling between MIMO equalization and clock recovery loops, using a midpoint output of the equalizer for timing estimation, instead of its final output. At least a portion of controlled Inter-Symbol Interference (ISI) is kept intact and the controlled ISI is compensated by an MLSE, right after carrier timing synchronization.

Abstract: System and method for digitally equalizing a data channel having wide channel impulse response for clock recovery of heavily ISI-induced received signals operating at one sample per symbol, according to which the received signal is pre-processed to provide a received signal with modified constellation, which is pre-processed for the decision process of signal with Inter-Symbol Interference by introducing controlled ISI to the received signal. The decision process is performed, based on a higher order vocabulary according to the introduced controlled ISI.

Abstract: System and method for equalizing a high bit rate optical communication channel in a symbol spaced adaptive Multiple-In-Multiple-Out (MIMO) system, where the optical communication channel carries a signal that is sampled at a symbol rate. Accordingly, Anti Aliasing Filtering (which introduces distortions in the form of Deterministic Inter Symbol Interference D-ISI) is applied in a MIMO channel, in order to reduce the aliasing effect associated with symbol rate sampling. The Polarization Mode Dispersions introduced in the optical communication channel are solely compensated by a MIMO Equalizer, which ignores the Deterministic ISI (D-ISI) distortion. Then the Deterministic ISI (D-ISI) distortion is solely compensated by an independent Deterministic Equalizer (DE).

Abstract: A method for estimating the phase of a modulated complex optical signal, according to which, the phase of the signal is isolated and the complex amplitude of the signal is digitized by a block of P samples. An adaptive filter minimizes phase-error between the phase of the received symbol and the phase of a sample, rotated by a phase correction factor, by iteratively performing a Block-Wise Phase LMS estimation on the samples using a step size parameter. During each iteration, the resulting correction factor consists of the sum of the estimated errors multiplied by this parameter, and the correction factor of previous iteration, which is updated, until obtaining the final correction factor from the last iteration. The samples constituting the received signal are recovered by adding the most updated correction factor to the phase of each sample and performing a decision regarding the phase of each sample.

Abstract: The present invention is directed to a MIMO equalization system and method, optimized for baud rate clock recovery in coherent symbol-spaced DP-QPSK Metro systems. According to this method, the Mueller & Muller timing function is extended to cope with controlled ISI induced signals, while decoupling between MIMO equalization and clock recovery loops, using a midpoint output of the equalizer for timing estimation, instead of its final output. At least a portion of controlled Inter-Symbol Interference (ISI) is kept intact and the controlled ISI is compensated by an MLSE, right after carrier timing synchronization.

Abstract: A system for digitally equalizing a data channel with heavily ISI-induced signals received after passing a data communication channel using a combination of a linear equalizer and a nonlinear equalizer, which comprises an ADC, for sampling a received signal and converting it to a digital form; a Linear Equalizer for pre-processing said received signal, said Linear Equalizer is adapted to pre-process a first group consisting of echoes/channel taps of the induced ISI, which are not equalized by said nonlinear equalizer, by eliminating the echoes/channel taps of said first group; pre-process a second group consisting of the combination of the entire echoes/channel taps of the induced ISI, by eliminating the echoes/channel taps of said second group; and a nonlinear equalizer for receiving the signals preprocessed by said Linear Equalizer and for further processing said preprocessed signals and eliminating the echoes/channel taps of the induced ISI to be equalized by said nonlinear equalizer, thereby compensating

Abstract: System and method for digitally equalizing a data channel having wide channel impulse response for clock recovery of heavily ISI-induced received signals operating at one sample per symbol, according to which the received signal is pre-processed to provide a received signal with modified constellation, which is pre-processed for the decision process of signal with Inter-Symbol Interference by introducing controlled ISI to the received signal. The decision process is performed, based on a higher order vocabulary according to the introduced controlled ISI.

Abstract: System and method for equalizing a high bit rate optical communication channel in a symbol spaced adaptive Multiple-In-Multiple-Out (MIMO) system, where the optical communication channel carries a signal that is sampled at a symbol rate. Accordingly, Anti Aliasing Filtering (which introduces distortions in the form of Deterministic Inter Symbol Interference D-ISI) is applied in a MIMO channel, in order to reduce the aliasing effect associated with symbol rate sampling. The Polarization Mode Dispersions introduced in the optical communication channel are solely compensated by a MIMO Equalizer, which ignores the Deterministic ISI (D-ISI) distortion. Then the Deterministic ISI (D-ISI) distortion is solely compensated by an independent Deterministic Equalizer (DE).

Abstract: A method for performing blind channel estimation for an MLSE receiver in a communication channel, according to which Initial Metrics Determination Procedure (IMDP) is performed using joint channel and data estimation in a decision directed mode. This is done by generating a bank of initial metrics that assures convergence, based on initial coarse histograms estimation, representing the channel and selecting a first metrics set M from the predefined bank. Then an iterative decoding procedure is activated during which, a plurality of decision-directed adaptation learning loops are carried out to perform an iterative histograms estimation procedure for finely tuning the channel estimation. Data is decoded during each iteration, based on a previous estimation of the channel during the previous iteration. If convergence is achieved, ISI optimization that maximizes the amount of ISI that is compensated by the MLSE is performed.