Dynamic impulse response model for nonlinear acoustic system and its application to acoustic echo canceller

We proposed a dynamic impulse response model for a nonlinear acoustic system and a nonlinear acoustic echo canceller based on this model. In an acoustic system with small loudspeakers and low-quality enclosures, acoustic signal paths between loudspeakers and microphones often include nonlinearity. Such paths cannot be represented with a conventional linear system. We investigated the impulse responses with various input signal levels and find that the responses differed with regularity in accordance with the level of the input signal. Thus, we propose a dynamic impulse response model based on this fact. In this model, the system response varies in accordance with the input signal levels and the nonlinearity can be approximated with a set of linear filters. We applied this model to an acoustic echo canceller, and experimental evaluations using a small acoustic system show that the echo cancellation performance of the proposed method is improved relative to that of the conventional method by 4 dB on average and 10 dB at maximum.