Abstract: Methods and systems are described for generating, using a voltage-controlled oscillator (VCO), a plurality of phases of a local clock signal, generating a phase-error signal using a phase comparator receive a phase of the local clock signal and a reference clock signal, and configured to output the phase-error signal, generating a frequency-lock assist (FLA) signal using a FLA circuit receiving one or more phases of the local clock signal and the reference clock signal, the FLA signal indicative of a magnitude of a frequency error between the reference clock signal and the local clock signal, and generating a VCO control signal using an error accumulator circuit receiving the phase-error signal and the FLA signal, and responsively providing the VCO control signal to the VCO to lock the local clock signal to the reference clock signal.
Abstract: An apparatus including a first circuit and a second circuit. The first circuit may be configured to determine values for a predefined metric for a plurality of tap positions within a range covered by a decision feedback equalizer (DFE). The values for a number of taps may be determined in parallel. The second circuit may be configured to set one or more floating taps of the DFE to tap positions based upon the values of the predefined metric. The floating taps in the decision feedback equalizer may be selected adaptively.
Type:
Grant
Filed:
July 13, 2010
Date of Patent:
May 14, 2013
Assignee:
LSI Corporation
Inventors:
Wing Faat Liu, Freeman Y. Zhong, Lizhi Zhong, Eric Zhang