A received signal is output to an echo path and, at the same time, it is divided into a plurality of subbands to generate subband received signals, which are applied to estimated echo paths in the respective subbands to produce echo replicas. The echo having propagated over the echo path is divided...http://www.google.com/patents/US5818945?utm_source=gb-gplus-sharePatent US5818945 - Subband echo cancellation method using projection algorithm
