Abstract: A timing recovery apparatus for signal reception in a data transmission system comprises an equalizer to equalize a received signal and a phase detector connected after the timing recovery equalizer that generates a clock tone from absolute values of the received signal after equalization.

Abstract: A timing recovery apparatus for signal reception in a data transmission system comprises an equalizer to equalize a received signal and a phase detector connected after the timing recovery equalizer that generates a clock tone from absolute values of the received signal after equalization.

Abstract: An optical communication system that comprises a transmitter adapted to generate a signal by modulating a transmission data as low power consumption symbols of an amplitude modulation format and a monitoring data (MD) as high power consumption symbols of the amplitude modulation format, the MD comprising at least one transmitter parameter and/or at least one receiver parameter of communicating the transmission data. A binary logarithm of a total number of the low power consumption symbols and the high power consumption symbols is a non-integer.

Abstract: The present invention relates to a multi-channel IM-DD optical transceiver comprising at least one transmitter and a receiver, and a method for equalizing input samples at an adjusted sampling phase using a quality parameter linearly proportional to a BER. The data transmission and reception use a single master channel and slave channels, which have a baud rate equal to or lower than the baud rate of the master channel. A reliable and identical clocking of all the channels is obtained through either the receiver clock of the master channel when they are received from a single transmitter or a reference clock whose frequency is higher than the highest clock frequency amongst all the channels when they are received from a combination of transmitters. An enhanced timing recovery circuit is also provided to select optimized finite impulse response filters, calculate filter coefficients and generate the receiver clock of the master channel.

Abstract: A binary encoder includes an input configured to receive a binary signal, an encoding processor configured to compute a plurality of different variations of the binary signal, combine each of the different variations with a different redundancy sequence to create a plurality of optional output binary sequences, and select one of the optional output binary sequences according to a binary digit prevalence, and an output configured to output the selected binary sequence. A decoder configured to identify a redundancy sequence of a received binary signal to select a transformation function according to the redundancy sequence and to convert the binary signal according to the transformation function.

Abstract: An optical communication system includes a transmission side system for multi-level pulse amplitude modulation (PAM) and a corresponding receiver side system, where the transmission side comprises a laser source providing an optical beam, a signal source of electrical signals to be modulated onto the optical beam, and a modulator coupled to the laser source and the signal source to modulate the electrical signals onto the optical beam using amplitude modulation and at least four signal levels, wherein the at least four signal levels are non-uniformly distributed. The receiver side includes a corresponding equalizer which is implemented as a filter of the form f1y+f2y2+f0, where y is the incoming signal and the parameters f0, f1 and f2 are obtained using an adaptive filter.

Abstract: A target constellation diagram determining method, a data sending method, and an apparatus are provided in accordance with the disclosure. The target constellation diagram determining method in accordance with the disclosure may include receiving, by a receiving device, training data that is generated and sent by a sending device based on each constellation point in an alternative constellation diagram. A detection region of each constellation point can then be determined based on a position of the training data in the alternative constellation diagram. A cumulative distance corresponding to the alternative constellation diagram can be obtained based on a distance between the detection regions of the constellation points.

Abstract: An optical communication system that comprises a transmitter adapted to generate a signal by modulating a transmission data as low power consumption symbols of an amplitude modulation format and a monitoring data (MD) as high power consumption symbols of the amplitude modulation format, the MD comprising at least one transmitter parameter and/or at least one receiver parameter of communicating the transmission data. A binary logarithm of a total number of the low power consumption symbols and the high power consumption symbols is a non-integer.

Abstract: An optical communication system includes a transmission side system for multi-level pulse amplitude modulation (PAM) and a corresponding receiver side system, where the transmission side comprises a laser source providing an optical beam, a signal source of electrical signals to be modulated onto the optical beam, and a modulator coupled to the laser source and the signal source to modulate the electrical signals onto the optical beam using amplitude modulation and at least four signal levels, wherein the at least four signal levels are non-uniformly distributed. The receiver side includes a corresponding equalizer which is implemented as a filter of the form f1y+f2y2+f0, where y is the incoming signal and the parameters f0, f1 and f2 are obtained using an adaptive filter.

Abstract: A binary encoder includes an input configured to receive a binary signal, an encoding processor configured to compute a plurality of different variations of the binary signal, combine each of the different variations with a different redundancy sequence to create a plurality of optional output binary sequences, and select one of the optional output binary sequences according to a binary digit prevalence, and an output configured to output the selected binary sequence. A decoder configured to identify a redundancy sequence of a received binary signal to select a transformation function according to the redundancy sequence and to convert the binary signal according to the transformation function.

Abstract: A target constellation diagram determining method, a data sending method, and an apparatus are provided in accordance with the disclosure. The target constellation diagram determining method in accordance with the disclosure may include receiving, by a receiving device, training data that is generated and sent by a sending device based on each constellation point in an alternative constellation diagram. A detection region of each constellation point can then be determined based on a position of the training data in the alternative constellation diagram. A cumulative distance corresponding to the alternative constellation diagram can be obtained based on a distance between the detection regions of the constellation points.

Abstract: The present invention relates to a multi-channel IM-DD optical transceiver comprising at least one transmitter and a receiver, and a method for equalizing input samples at an adjusted sampling phase using a quality parameter linearly proportional to a BER. The data transmission and reception use a single master channel and slave channels, which have a baud rate equal to or lower than the baud rate of the master channel. A reliable and identical clocking of all the channels is obtained through either the receiver clock of the master channel when they are received from a single transmitter or a reference clock whose frequency is higher than the highest clock frequency amongst all the channels when they are received from a combination of transmitters. An enhanced timing recovery circuit is also provided to select optimized finite impulse response filters, calculate filter coefficients and generate the receiver clock of the master channel.

Abstract: The present invention relates to an interleaving and de-interleaving method, an interleaver and a de-interleaver. The interleaving method includes: receiving N×M frames of data, and sequentially storing, with each frame as a unit, the N×M frames of data in storage space indicated by N×M addresses of a first storage unit; transferring the data stored in the storage space indicated by an ((X?1)×M+Y+1)th address of the first storage unit to the storage space indicated by a (Y×N+X)th address of a second storage unit; and according to an address sequence, outputting the data stored in the space indicated by the N×M addresses of the second storage unit frame by frame. The interleaving and de-interleaving solutions of the present invention have low implementation complexity, and high capacity of correcting a burst bit error.

Abstract: The invention relates to an apparatus for characterizing a chromatic dispersion of an optical receive signal, the apparatus comprising a delay means for delaying the optical receive signal by a predetermined time delay to obtain a delayed signal, the delayed signal being delayed with respect to the optical receive signal, a phase detecting means for determining a first value indicating a phase delay of the optical receive signal, and for determining a second value indicating a phase delay of the delayed signal, and a processor for determining a chromatic dispersion indicator upon the basis of the first value and the second value, the chromatic dispersion indicator characterizing the chromatic dispersion.

Abstract: The invention relates to an apparatus for characterizing a chromatic dispersion of an optical receive signal, the apparatus comprising a delay means for delaying the optical receive signal by a predetermined time delay to obtain a delayed signal, the delayed signal being delayed with respect to the optical receive signal, a phase detecting means for determining a first value indicating a phase delay of the optical receive signal, and for determining a second value indicating a phase delay of the delayed signal, and a processor for determining a chromatic dispersion indicator upon the basis of the first value and the second value, the chromatic dispersion indicator characterizing the chromatic dispersion.

Abstract: The invention relates to a method for evaluating a performance of a forward error correction code used for coding a sequence of known transmit data symbols, the method comprising: receiving a sequence of receive data symbols responsive to a transmission of the known sequence of transmit data symbols over a communications channel, wherein the known sequence of transmit data symbols is transmitted over the communications channel without being coded by the forward error correction code; providing a sequence of extended parity bits based on the known transmit data symbols and based on a parity check matrix of the forward error correction code; and providing the performance of the forward error correction code based on the sequence of extended parity check bits.

Abstract: A chromatic dispersion estimator for estimating a chromatic dispersion in an input signal block comprises a transformer for transforming the input signal block into a transformed signal block in frequency domain, a chromatic dispersion compensator for compensating a certain chromatic dispersion in the transformed signal block to obtain a compensated transformed signal block, an inverse transformer for inversely transforming the compensated transformed signal block into time domain to obtain an output signal, an adaptive filter for filtering the output signal to obtain a filtered signal, and a determiner for determining upon the basis of the filtered signal whether the certain chromatic dispersion corresponds to the chromatic dispersion in the input signal block.

Abstract: A skew estimator for estimating a skew between a first signal of a first data path and a second signal of a second data path in a coherent receiver is provided. The skew estimator comprises a phase detector and an integrator. The phase detector is configured to detect a phase of the first signal or the second signal to obtain a phase signal. Further, the integrator is configured to integrate the obtained phase signal to provide an estimated skew.

Abstract: A signal processing apparatus configured to correct a distortion introduced by a signal processing path into a processed signal comprising a transformer that transforms the processed signal into a transformed signal in frequency domain, a processor that determines a first correction function and a second correction function upon the basis of a transfer function of the signal processing path, a first multiplier that multiplies values of the transformed signal with coefficients of the first correction function to obtain a first corrected signal, a signal reverser that reverses an order of values in a copy of the transformed signal to obtain a reversed transformed signal, a second multiplier that multiplies values of the reversed transformed signal with coefficients of the second correction function to obtain a second corrected signal, and an adder that adds the first corrected signal and the second corrected signal to obtain a corrected output signal.

Abstract: Phase detection methods are provided. According to a first embodiment, a signal is sampled in order to obtain an amplitude sample. Then an absolute value of the difference of the amplitude sample minus an average of amplitude samples is calculated. According to a second embodiment, the signal is sampled at a first and second phase. This results in first and second amplitude samples which are compared to a first and second plurality of thresholds, respectively, in order to assign first and second weighting values to each first and second amplitude sample, respectively, depending on to which range between two adjacent thresholds the first and second amplitude sample belong. Then the sum or difference of said first and second weighting values is calculated.