Coupled adaptive filters for acoustic echo control and noise reduction

Presents new adaptive algorithms for acoustic echo control and noise reduction which employ one, two, or possibly more microphone signals. The new algorithms accommodate high echo attenuation and lead to implementations with reduced complexity. These algorithms combine a conventional FIR echo canceller with a second NLMS-adapted FIR filter which attenuates residual echoes. The paper presents a one-microphone system with improved echo attenuation and a two-microphone system which attenuates acoustic echoes as well as ambient noise and near end speech reverberation. The algorithms can be interpreted as a frequency selective generalization of the well known voice controlled switch. The paper explains the algorithms and presents experimental results in real acoustic environments