Dynamic threshold updating circuit for a maximum likelihood detector using both positive and negative comparators

摘要

A maximum likelihood detector for a continuous time disk drive read channel includes a dynamic threshold updating circuit for a maximum likelihood detector using both positive and negative comparators for detecting the positive and negative peaks of an input signal; this includes comparing the input signal with at least one present dynamic threshold to produce positive and negative binary gating signals; a control circuit responsive to the binary gating signals, to the input signal, and to the peak detector circuit which identifies qualified input signal peaks; and a threshold update circuit responsive to the identification of qualified input signal peaks, which adjusts the present dynamic threshold by the difference between the input signal and the present dynamic threshold to obtain the next dynamic threshold.