Patent ID: 6185301
Filing Date: 2001-02-06
Classification: H04B

Abstract:
An echo canceler comprising:a first adaptive filter circuit for receiving a receiving signal, calculating first tap coefficients using a first convergence coefficient, and generating a first pseudo echo signal in accordance with said first tap coefficients and said receiving signal;a first subtracter, connected said first adaptive filter circuit, for receiving a transmitting signal and subtracting said first pseudo echo signal from said transmitting signal to generate a first error signal;a second adaptive filter circuit for receiving said received signal, calculating second tap coefficients using a second convergence coefficient smaller than said first convergence coefficient, and generating a second pseudo echo signal in accordance with said second tap coefficients and said received signal;a second subtracter, connected to said second adaptive filter circuit, for receiving said transmitting signal and subtracting said second pseudo echo signal from said transmitting signal to generate a second error signal;a control circuit, connected to said first and second adaptive filter circuits and said first and second subtractors, for selecting one set of said first tap coefficients and said second tap coefficients in accordance with said received signal, said transmitting signal, and said first and second error signals;a third adaptive filter circuit, connected to said control circuit, for receiving said received signal and said transmitting signal and generating a third pseudo echo signal in accordance with the set of tap coefficients selected by said control circuit and said received signal; anda third subtractor, connected to said third adaptive filter circuit, for subtracting said third pseudo echo signal from said transmitting signal to generate a third error signal.