Patent ID: 6901141
Filing Date: 2005-05-31
Classification: H04M

Abstract:
1. An echo canceller that eliminates echoes produced in an echo path formed between a loudspeaker that converts receiving signals into voice output and a microphone that converts voice input into sending signals, the echo canceller comprising: an adaptive digital filter, designed to imitate transmission characteristics of the echo path, that generates pseudo echo signals responsive to a part of the receiving signals; a subtracter that subtracts the pseudo echo signals from the sending signals containing echo noise that is input to the microphone from the echo path, to provide an echo canceled sending signal; wherein tap coefficients of said adaptive digital filter are modified responsive to the part of the receiving signals and a part of the echo canceled sending signal; and an attenuator that attenuates the sending signals containing echo noise so that an amplitude level of the echo noise matches an amplitude level of the pseudo echo signals, and that provides the attenuated sending signals to said subtracter as the sending signals for subtraction.