A Distortion Reducing Subband Limiter Implementation for Conference Phones

Distortion, most often caused by the loudspeaker, is a practical problem in acoustic echo cancellation-based conference phones. Typically, this distortion varies significantly with the frequency. This paper presents an implementation of a distortion reducing subband limiter to be used in conjunction with an acoustic echo canceller in a commercial conference phone, yielding improved cancellation performance. Verification of the performance was performed through evaluation of a fix-point real-time implementation.