The disclosed embodiments provide a system that implements a low-aperture-delay sampler. The system includes a sampler input, which receives an input signal, and a clock input, which receives a clock signal. The system also includes: a first sampling channel, which samples the input signal when the clock signal is low and is associated with a previous clock phase; and a second sampling channel, which samples the input signal when a rising edge is received in the clock signal, wherein the rising edge is associated with a present clock phase. The system additionally includes a combining mechanism, which combines outputs of the first and second sampling channels to produce a sampler output with a significantly reduced aperture delay.

The disclosed embodiments provide a system that implements a low-aperture-delay sampler. The system includes a sampler input, which receives an input signal, and a clock input, which receives a clock signal. The system also includes: a first sampling channel, which samples the input signal when the clock signal is low and is associated with a previous clock phase; and a second sampling channel, which samples the input signal when a rising edge is received in the clock signal, wherein the rising edge is associated with a present clock phase. The system additionally includes a combining mechanism, which combines outputs of the first and second sampling channels to produce a sampler output with a significantly reduced aperture delay.

Methods and systems are described for sampling a data signal using a data sampler operating in a data signal processing path having a decision threshold associated with a decision feedback equalization (DFE) correction factor, measuring an eye opening of the data signal by adjusting a decision threshold of a spare sampler operating outside of the data signal processing path to determine a center-of-eye value for the decision threshold of the spare sampler, initializing the decision threshold of the spare sampler based on the center-of-eye value and the DFE correction factor, generating respective sets of phase-error signals for the spare sampler and the data sampler responsive to a detection of a predetermined data pattern, and updating the decision threshold of the data sampler based on an accumulation of differences in phase-error signals of the respective sets of phase-error signals.

A system for receiving signals transmitted via serial links includes an analog-to-digital converter configured to sample the first analog signal at a first rate, and generate a first digital input signal having a second data rate. The system also includes a decimator coupled to an output of the equalizer and configured to downsample the first equalized signal to a decimated signal having the first data rate. The system further includes a fast equalization module for determining output data corresponding to the communications signal. The fast equalization module includes a filter to access an output of the equalizer, a second slicer module to access an output of the filter and produce a data output corresponding to the communications signal, a lookup table to provide filtering coefficients to the filter, and a coefficient improvement module to improve the coefficients based on an error signal from the filter.

An adaptive equalization circuit includes: a first filter configure to perform filtering on an input signal based on a tap coefficient; an applying circuit configured to apply, to the signal, noise outside a band of the signal; and a controller configured to set, for the first filter, the tap coefficient that compensates for transmission line characteristics of the signal, based on the signal to which the noise is applied by the applying circuit.

Methods and systems are described for sampling a data signal using a data sampler operating in a data signal processing path having a decision threshold associated with a decision feedback equalization (DFE) correction factor, measuring an eye opening of the data signal by adjusting a decision threshold of a spare sampler operating outside of the data signal processing path to determine a center-of-eye value for the decision threshold of the spare sampler, initializing the decision threshold of the spare sampler based on the center-of-eye value and the DFE correction factor, generating respective sets of phase-error signals for the spare sampler and the data sampler responsive to a detection of a predetermined data pattern, and updating the decision threshold of the data sampler based on an accumulation of differences in phase-error signals of the respective sets of phase-error signals.

Methods and systems are described for sampling a data signal using a data sampler operating in a data signal processing path having a decision threshold associated with a decision feedback equalization (DFE) correction factor, measuring an eye opening of the data signal by adjusting a decision threshold of a spare sampler operating outside of the data signal processing path to determine a center-of-eye value for the decision threshold of the spare sampler, initializing the decision threshold of the spare sampler based on the center-of-eye value and the DFE correction factor, generating respective sets of phase-error signals for the spare sampler and the data sampler responsive to a detection of a predetermined data pattern, and updating the decision threshold of the data sampler based on an accumulation of differences in phase-error signals of the respective sets of phase-error signals.

A system for receiving signals transmitted via serial links includes an analog-to-digital converter configured to sample the first analog signal at a first rate, and generate a first digital input signal having a second data rate. The system also includes a decimator coupled to an output of the equalizer and configured to downsample the first equalized signal to a decimated signal having the first data rate. The system further includes a fast equalization module for determining output data corresponding to the communications signal. The fast equalization module includes a filter to access an output of the equalizer, a second slicer module to access an output of the filter and produce a data output corresponding to the communications signal, a lookup table to provide filtering coefficients to the filter, and a coefficient improvement module to improve the coefficients based on an error signal from the filter.

An adaptive equalization circuit includes: a first filter configure to perform filtering on an input signal based on a tap coefficient; an applying circuit configured to apply, to the signal, noise outside a band of the signal; and a controller configured to set, for the first filter, the tap coefficient that compensates for transmission line characteristics of the signal, based on the signal to which the noise is applied by the applying circuit.

Methods and systems are described for sampling a data signal using a data sampler operating in a data signal processing path having a decision threshold associated with a decision feedback equalization (DFE) correction factor, measuring an eye opening of the data signal by adjusting a decision threshold of a spare sampler operating outside of the data signal processing path to determine a center-of-eye value for the decision threshold of the spare sampler, initializing the decision threshold of the spare sampler based on the center-of-eye value and the DFE correction factor, generating respective sets of phase-error signals for the spare sampler and the data sampler responsive to a detection of a predetermined data pattern, and updating the decision threshold of the data sampler based on an accumulation of differences in phase-error signals of the respective sets of phase-error signals.