Patent ID: 6215818
Filing Date: 2001-04-10
Classification: H04L

Abstract:
A method of convergence monitoring in an adaptive decision feedback equalizer having a quadrature amplitude modulation (QAM) slicer receiving as input a complex input signal, comprising the steps of:(a) calculating an average output error of the equalizer by calculating a difference of the complex input signal having an in-phase component and a quadrature component before and after the QAM slicer, adding an absolute value of the in-phase component of the input signal to an absolute value of the quadrature component of the input signal to obtain a sum of the error components, and integrating the sum of the error components over a prescribed time;(b) estimating a signal-to-noise ratio (SNR) based on the average output error; and(c) comparing the estimated SNR to an SNR threshold, wherein the equalizer is not properly converged when the estimated SNR is lower than the SNR threshold.