A multi-channel echo canceller comprises a set of subtractors connected respectively in communication channels for respectively receiving a signal from a respective microphone and cancelling an echo contained in it with a cancelling signal, and a set of adaptive filters associated respectively with the...http://www.google.com/patents/US5371789?utm_source=gb-gplus-sharePatent US5371789 - Multi-channel echo cancellation with adaptive filters having selectable coefficient vectors
