A method of initializing a filter in an echo canceller as used in a telephone system that includes hybrid transformers for connecting unidirectional lines to bidirectional lines and vice versa. Said method includes the steps of successively transmitting sequences of real and imaginary components of a...http://www.google.de/patents/US4593161?utm_source=gb-gplus-sharePatent US4593161 - Method of initializing a filter in an echo canceller and communication system using said method
