Patent ID: 8811464

Claim:
An apparatus for tuning an equalizer, the apparatus comprising: a tuning logic configured to adaptively determine settings for the equalizer to undo effects of a backplane channel on a signal carried by the backplane channel, wherein the equalizer includes a three-tap filter with a main tap f 0 a precursor tap f −1 and a postcursor tap f 1 , the tuning logic comprising: a symmetric search logic configured to repeatedly and symmetrically vary values of the main tap f 0 the precursor tap f −1 and the postcursor tap f 1 to determine a desired boost setting for the three-tap filter, wherein the symmetric search logic is configured to determine a signal to noise ratio (SNR) for a signal carried on the backplane channel for each iteration of symmetrically varying the values, and wherein the symmetric search logic is configured to symmetrically vary the values over multiple iterations to symmetrically search over a plurality of values for the three-tap filter, and an asymmetric search logic configured to repeatedly and asymmetrically vary values of the precursor tap f −1 and the postcursor tap f 1 to determine a desired phase response for the three-tap filter, wherein the asymmetric search logic is configured to determine a signal to noise ratio (SNR) for the signal carried on the backplane channel for each iteration of asymmetrically varying the values, and wherein the asymmetric search logic is configured to asymmetrically vary the values over multiple iterations to asymmetrically search over the plurality of values for the three-tap filter.