Implementation and evaluation of an acoustic echo canceller using duo-filter control system

The developed acoustic echo canceller uses an exponentially weighted step-size projection algorithm and a duo-filter control system to achieve fast convergence and high speech quality. The duo-filter control system has an adaptive filter and a fixed filter, and uses variable-loss insertion. Evaluation of this system with multi-channel A/D and D/A converters showed that (1) the convergence speed is under 1.5 seconds for speech input when the adaptive filter length is 125 ms, (2) the residual echo level is nearly as low as the ambient noise level (average: under −20 dB; maximum: under −35 dB), and (3) near-end speech is sent with no disturbance during double talk.