N. Tangsangiumvisai, J. A. Chambers, and A. G. Constantinides
Higher-order time-varying allpass filters for signal decorrelation in stereophonic acoustic echo cancellation
IEE Electronics Letters, vol. 35, no. 1, pp. 88-90, 1999.

Abstract

A new technique is presented for the purpose of decorrelating the input signals in stereophonic acoustic echo cancellation (SAEC) by means of time-varying allpass filters. The controllable and almost linear phase response of higher-order allpass filters is exploited in this context and a particular type of time variation is used to vary the parameters of such filters. Simulation results are presented based on real stereophonic signals and supported by subjective listening tests.