1978-11-16
1980-09-30
Wolff, John H.
179 1HF, H04M 160
Patent
active
042257549
ABSTRACT:
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.
REFERENCES:
patent: 4007341 (1977-02-01), Sourgens et al.
patent: 4024357 (1977-05-01), Sourgens et al.
patent: 4057696 (1977-11-01), Gitlin et al.
Bernard Solange
Lajotte Dominique
Michelon Francois
Sourgens Jacques
Compagnie Industrielle des Telecommunications Cit-Alcatel
Popek Joseph A.
Wolff John H.
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