EXPERIMENTAL RESULTS WITH INCREASED BANDWIDTH ANALYSIS FILTERS IN OVERSAMPLED, SUBBAND ACOUSTIC ECHO CANCELERS

The motivation for adaptive filtering in subbands stems from two well-known problems in least-mean square full-band adaptive filtering. First, the convergence and tracking can be very slow if the input correlation matrix is ill conditioned, as in the case with speech input. Second, very high order adaptive filters are computationally expensive. One problem with adaptive filtering in subbands is the slow, asymptotic convergence associated with oversampled systems. Increasing the bandwidth of analysis filters relative to the synthesis filters is proposed to reduce the slow asymptotic convergence. This letter will motivate this approach and present experimental results illustrating the benefits of this modification.