NON-CONSTANT ECHO RETURN LOSS FOR TELEPHONE TERMINAL WITH HANDSFREE

摘要

A telephone terminal having handsfreefunctionality is provided with an audio system whichcontrols echo return loss while permitting virtualfull-duplex operation. The system, which has a variolosserin both the transmit and receive path and an acoustic echocanceller, also has a complementary variolosser whichintroduces additional echo return loss only when requiredand as a function of the state of the system.