A loudspeaking telephone has a differential coupler (3) connecting a two-way two-wire telephone line (4) to separate transmission and reception channels (1 and 2 respectively) including respectively a microphone (5) and a loudspeaker (7). A first transversal filter (10) synthesizes an acoustic echo signal ya which is subtracted from the microphone signal to deliver a substantially echo-free signal to the transmission channel. Likewise a second transversal filter (11) synthesizes an electrical echo signal to deliver a substantially echo-free signal to the reception channel.
申请公布号
US4225754(A)
申请公布日期
1980.09.30
申请号
US19780961176
申请日期
1978.11.16
申请人
COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS CIT-ALCATEL
发明人
BERNARD, SOLANGE;LAJOTTE, DOMINIQUE;MICHELON, FRANCOIS;SOURGENS, JACQUES