Systems and methods are described for transmitting data over physical channels to provide a high bandwidth, low latency interface between a transmitting device and a receiving device operating at high speed with low power utilization. Communication is performed using group signaling over sets of four wires using a vector signaling code, where each wire of a set carries a low-swing signal that may take on one of four signal values. Topologies and designs of wire sets are disclosed with preferred characteristics for group signaling communications.

An example method for clock and data recovery (CDR) includes generating, in a set of slicers of a receiver, in addition to a data signal and a first error signal, at least one additional error signal. The method further includes receiving, at a frequency detector (FD) of a CDR unit of the receiver, the data signal, the first error signal, and the at least one additional error signal, and processing them to generate a FD output. The method still further includes multiplying the FD output by a user-defined FD gain, and adding the FD output, as multiplied by the FD gain, in a frequency path of the CDR unit.

Embodiments are related to systems and methods for data processing, and more particularly to systems and methods for enhancing margin in a serial data transfer.

A decision feedback equalizer includes a positive signal line, a negative signal line, a sense amplifier, a feedback driver, a load unit, a differential driver, and a charge pump. The differential driver maintains a difference between the first voltage of the positive signal line and the second voltage of the negative signal line at a last time point of the normal period to be equal to or greater than the reference voltage by adjusting strength of the positive input current corresponding to a positive input signal and strength of the negative input current corresponding to a negative input signal based on a temperature signal. The charge pump provides a positive offset voltage and a negative offset voltage to the positive signal line and the negative signal line, respectively. The positive offset voltage and the negative offset voltage are used to maintain an average voltage of the first voltage and the second voltage at the last time point of the normal period at a first value.

A semiconductor integrated circuit according to an embodiment includes an A/D converter, first and second equalizer circuits, and first and second controllers. The first equalizer circuit includes a first tap. The first and second equalizer circuits receive a signal based on a digital signal, and output first and second signals, respectively. The first controller adjusts a phase of a clock signal based on the first signal. The second controller an operation of adjusting a control parameter including a tap coefficient. In the operation, the second controller adjusts a tap coefficient of each of taps of the second equalizer circuit, and adjusts a tap coefficient of the first tap based on an adjustment result of each tap coefficient of the second equalizer circuit.

A distortion compensation system includes a first communication node including a first reception unit including an equalizer configured by a first digital filter unit and a first transmission unit including an emphasis circuit configured by a second digital filter unit, and a second communication node including a second transmission unit transmitting a training pattern before receiving normal data from the first communication node. The equalizer converges a filter constant of the first digital filter unit so that an error of the received training pattern is converged. The first transmission unit performs a distortion compensation using the converged filter constant of the first digital filter unit as at least a part of a filter constant of the second digital filter unit of the emphasis circuit, and then transmits the data.

A memory module includes a plurality of semiconductor memory devices associated with a same module board. The plurality of semiconductor memory devices configured to simultaneously perform a training operation, the plurality of semiconductor memory devices including a reception interface circuit configured to perform the training operation to search for selected equalization coefficients of an equalizer based on a training pattern from a memory controller, and transmit a training information signal to the memory controller in a training mode in response to a training command from the memory controller, the training information signal including the selected equalization coefficients.

A transmitting circuit includes: a multiplexer configured to output a third digital signal obtained by alternately synthesizing a first digital signal of a predetermined cycle length and a predetermined data rate with a second digital signal of the predetermined cycle length and the predetermined data rate; a first selector configured to output the first digital signal in a first state and output the third digital signal in a second state that is different from the first state; a second selector configured to output the second digital signal in the first state and output the third digital signal in the second state; a first driver circuit configured to output a signal corresponding to a signal output from the first selector; and a second driver circuit configured to output a signal corresponding to a signal output from the second selector.

Data symbols in an input signal are detected with a slicer of a DFE of a transceiver device. An output of a feedback filter of the DFE is generated, during a particular clock cycle, based on a first set of one or more data symbols detected during first one or more previous clock cycles and a second set of one or more data symbols detected during second one or more previous clock cycles. The second set is separated from the first set by a third set of one or more data symbols detected during third one or more clock cycles that occur after the first one or more clock cycles and before the second one or more clock cycles, where the output is generated without use of the third set of symbols. The output is subtracted from the input signal to generate an equalized input to the slicer.

An example method for clock and data recovery (CDR) includes generating, in a set of slicers of a receiver, in addition to a data signal and a first error signal, at least one additional error signal. The method further includes receiving, at a frequency detector (FD) of a CDR unit of the receiver, the data signal, the first error signal, and the at least one additional error signal, and processing them to generate a FD output. The method still further includes multiplying the FD output by a user-defined FD gain, and adding the FD output, as multiplied by the FD gain, in a frequency path of the CDR unit.