Optimization of an acoustic echo canceller combined with adaptive gain control

This contribution deals with the application of hands-free algorithms in wide-band telephone systems with limited computing resources. The basis is the combination of an acoustic echo canceller and an adaptive gain control method. The paper describes how the effect of the echo canceller can be optimized without increasing the computational expense. This is achieved by extending the length of the adaptive filter at the cost of a reduced affected frequency range. The study shows to which extent one can concentrate on the low frequency portion of the acoustic echoes in a wide-band application, if a suitable additional gain control method is available. The optimization is accomplished using a simple room model. Real-time measurements were carried out using an implementation of the complete hands-free system on a single DSP