The effects of non-stationary signal characteristics on the performance of adaptive audio restoration systems

The degrading effects of nonstationary and abruptly changing signal characteristics on the performance of a particular class of restoration systems, namely those which use two sources of information, are discussed. The system considered is the adaptive noise suppression system. In this system abrupt changes in signal statistics result in transient degradations in the form of excessive suppression of some signal frequency components and or inadequate suppression of noise frequency components. Abrupt changes are detected using an appropriate distance between two autoregressive models of the signal. After detection of an abrupt change the adaptation gain is increased and/or the filter parameters are reinitialized in order to minimize the degradation