Patent ID: 8837573
Filing Date: 2014-09-16
Classification: H03G,H04L

Abstract:
1. An interface circuit for compensating for gain changes of an N-level pulse amplitude modulation (PAM-N) modulated signal, N being an integer, comprising: a number of N−1 comparators for comparing the PAM-N modulated signal to N−1 configurable thresholds, wherein the PAM-N modulated signal was also equalized and the N−1 configurable thresholds are N−1 different voltage levels; a compensation comparator for tracking gain changes in the input PAM-N modulated signal by comparing the input PAM-N modulated signal to a compensation threshold; and a compensation circuit for changing at least one of the N−1 configurable thresholds of the N−1 comparators based on an output of the compensation comparator, thereby offsetting a crossing point of at least one comparator of the N−1 comparators respective of the at least one of the N−1 configurable thresholds to compensate for gain changes in the input PAM-N modulated signal, wherein the compensation circuit further comprises: