A postfilter for echo and noise reduction avoiding the problem of musical tones

In this paper we address the problem of acoustic echo cancellation and noise reduction for narrow and wide band telephone applications. We combine a conventional echo canceller with a postfilter implemented in the frequency domain and derive an algorithm for the simultaneous attenuation of residual echo and noise. The main goals are a low level natural sounding background noise without artifacts such as musical tones, and an inaudible residual echo. This is achieved by considering the masking properties of the human auditory system. Simulation results verify that these goals are reached, while the distortion of the near end speech is comparable to conventional algorithms. Audio demonstrations are available via Internet from http://www.ind.rwth-aachen.de.