Circuit and method of double talk detection for use in handsfree telephony terminals

摘要: The invention provides an audio subsystem for use in a telephone terminal operable handsfree mode and comprises receive path including transducer generating signals from received signal transmit converting to electrical transmission far-end user. An acoustic echo canceller is communicatively coupled between the includes subtractor circuit connected serially with transducer. responsive control controlling circuit. means detecting near-end talking condition first measuring level of total energy out-of-telephony-band components comparing represented by output measurement predetermined threshold. If measured exceeds threshold, activity deemed exist. There also provided second on it threshold whereby if latter exceeded, determined Thus, both exceed their respective double talk situation