AN ADAPTIVE DUAL FILTER ECHO CANCELLATION METHOD

摘要

In a dual filter echo cancellation method a new quality measure (qa, qp) provides the basis for a new filter selection and transfer method. The quality measure represents the performance of a filter in the adaptive echo canceller. According to the method, a correlation measure between an echo containing signal and an echo estimation signal produced by said filter is estimated. A power measure of a residual signal, formed by the difference between said echo estimation signal and said echo containing signal, is estimated. The quality measure is calculated by dividing said estimated correlation measure by said estimated power measure. An adaptive and programmable filter is used in the echo cancellation and the quality measures for them both are calculated and compared. The best of the two filters, as determined by the quality measure, is used for modelling the echo path (570, 580) and its filter coefficients are copied to the other filter.