A speakerphone which employs non-linear amplifiers to compress transmit and receive signals, and level detectors to determine levels of the compressed transmit and receive signals. Compressed transmit and receive signal levels are compared against one another by a comparator with hysteresis, ...http://www.google.fr/patents/US5692042?utm_source=gb-gplus-shareBrevet US5692042 - Speakerphone controlled by a comparator with hysteresis
Speakerphone controlled by a comparator with hysteresis
