Accordingly embodiments herein disclose a quarter rate speculative DFE. The quarter rate speculative DFE includes a plurality of sampler circuits connected to an input terminal. The plurality of sampler circuits are configured to sample an input signal into a plurality of data samples in parallel. A plurality of quarter rate look ahead circuit connected to the plurality of sampler circuits. The plurality of quarter rate look ahead circuit is configured to simultaneously perform an align operation and a look ahead operation on the plurality of data samples based on the different clock phases to obtain a plurality of latched outputs. A plurality of multiplexers connected to the plurality of quarter rate look ahead circuit. The plurality of multiplexers is configured to generate two speculative data streams by multiplexing respective correction coefficients of each of the plurality of latched outputs.

A sequence detection device includes a decision-feedback equalizer (DFE), a combining circuit, a decision circuit, and a sequence detection circuit. The DFE processes a symbol decision signal to generate a first equalized signal. The combining circuit combines a data signal and the first equalized signal to generate a sample signal. The decision circuit performs hard decision upon the sample signal to generate the symbol decision signal. The sequence detection circuit performs sequence detection upon the data signal to generate and output a symbol sequence. Regarding the sequence detection, the sequence detection circuit selects branches for branch metric calculation according to at least the symbol decision signal.

According to one embodiment, a semiconductor integrated circuit includes first and second power supply lines, first and second nodes, and first and second circuits. The first circuit is configured to supply a first current to the second power supply line, from the first node or the second node. The second circuit is configured to supply a second current from the first power supply line to the first node based on a magnitude of the first current, and to supply a third current from the first power supply line to the second node based on the magnitude of the first current.

Systems and methods for implementation of modified decision feedback equalization. In one embodiment, a method, includes sweeping a reference voltage signal across a set of voltages to find a center point of an eye diagram, determining whether an asymmetry is present in the eye diagram relative to the center point of the eye diagram, and when an asymmetry is determined to be present, generating a control signal to select a mode of decision feedback equalization to be applied to an input data bit.

Provided is a reception device and a communication system. The reception device includes a compensation circuit connected to a transmission line that is connected to each of a plurality of transmission devices. The compensation circuit compensates a plurality of data signals received from the plurality of transmission devices, respectively, in time division. The reception device further includes an adjustment circuit that adjusts operation of the compensation circuit based on a plurality of training signals received from the plurality of transmission devices.

Embodiments are disclosed for facilitating an end-to-end link channel with one or more lookup tables for equalization. An example system includes a first transceiver and a second transceiver. The first transceiver includes a clock data recovery (CDR) circuit configured to receive communication data from a switch and to manage a lookup table associated with equalization of the communication data. The first transceiver also includes a first driver circuit communicatively coupled to the CDR circuit and configured to generate an electrical signal associated with the communication data. The second transceiver includes a second driver circuit, communicatively coupled to the first transceiver, that is configured to receive the electrical signal from the first transceiver and to modulate a laser source based on the electrical signal to generate an optical signal via the laser source.

Embodiments of the disclosure include signal processing methods to reduce crosstalk between signal lines of a channel bus using feed forward equalizers (FFEs) configured smear pulse response energy transmitted on signal lines of the channel to reduce pulse edge rates. The coefficients for the FFE may be based on crosstalk interference characteristics. Smearing or spreading pulse response energy across a longer time period using a FFE increases inter-symbol interference (ISI). To counter increased inter-symbol interference caused by smearing pulse response energy, receivers configured to recover symbol data transmitted on the channel bus may each include respective decision-feedback equalizers (DFEs) that are configured to filter ISI from transmitted symbols based on previous symbol decisions of the channel. The combination of the FFE configured to smear pulse responses and the DFE to filter ISI may improve data eye quality for recovery of transmitted data on a channel bus when crosstalk dominates noise.

A memory device including a receiving circuit is provided. The receiving circuit of the memory device includes a first path receiving a received signal and outputting the received signal directly as a first corrected signal in a current clock signal, a second path holding or tracking the received signal and outputting a second corrected signal in the current clock signal, wherein the second corrected signal is held in a previous clock signal, a summing circuit summing the first corrected signal and the second corrected signal and outputting a summed received signal, and a decision feedback equalizer comparing the summed received signal with a reference signal to decide equalized data and outputting the equalized data in the current clock signal.

Embodiments are disclosed for facilitating an end-to-end link channel with one or more lookup tables for equalization. An example system includes a first transceiver and a second transceiver. The first transceiver includes a clock data recovery (CDR) circuit configured to receive communication data from a switch and to manage a lookup table associated with equalization of the communication data. The first transceiver also includes a first driver circuit communicatively coupled to the CDR circuit and configured to generate an electrical signal associated with the communication data. The second transceiver includes a second driver circuit, communicatively coupled to the first transceiver, that is configured to receive the electrical signal from the first transceiver and to modulate a laser source based on the electrical signal to generate an optical signal via the laser source.

An equalizing circuit includes a first current summer that receives a data signal and a first plurality of feedback signals, a first multiplexer that selects a first sampling clock signal from a plurality of clock signals using a signal that indicates a mode of operation of the equalizing circuit, and a first slicer that samples the output of the first current summer in accordance with timing provided by the first sampling clock signal. The equalizing circuit can have a second current summer that receives the data signal and a second plurality of feedback signals, a second multiplexer that selects a second sampling clock signal from the plurality of clock signals using the signal that indicates the mode of operation of the equalizing circuit, and a second slicer that samples the output of the second current summer according to timing provided by the second sampling clock signal.