Patent ID: 7230783
Filing Date: 2007-06-12
Classification: G11B

Abstract:
1. Apparatus to mitigate distortion of read signals from at least one magneto-resistive read head, said read signals provided to a read channel having at least one analog to digital converter to convert analog read signals to digital and at least one digital equalizer having an input and an output, said apparatus comprising: digital peak measurement apparatus configured to sense said output of said at least one digital equalizer, and provide average positive peak values and average negative peak values of said digital equalizer output; and control apparatus configured to respond to said provided average positive peak values and average negative peak values, to iteratively determine asymmetry of said average positive peak values and average negative peak values and estimate a cancellation slope of said asymmetry and a convergence cancellation term relationship; from said asymmetry and estimated cancellation slope, to iteratively estimate said convergence cancellation term; and to feedback said convergence cancellation term to modify said digital read signals from said at least one analog to digital converter for said input of said at least one digital equalizer.