Telephone set in which an echo signal is effectively cancelled in spite of being provided with a plurality of sound producing units
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Dec 16, 1997
Grant Date -
N/A
app pub date -
Mar 20, 1995
filing date -
Mar 18, 1994
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
In a telephone set having a receiver (42) and a loudspeaker (39), a switch circuit (37) selects supply of a reception speech signal, transmitted from a counterpart section (60), to the receiver or the loudspeaker in response to a selection signal. A first adaptive echo canceller (43a) produces a pseudo echo signal with reference to the reception speech signal. A controller (44) controls operation of the first adaptive echo canceller in response to the selection signal to optimize the pseudo echo signal. A first digital adder (35a) carries out a particular calculation between the pseudo echo signal and a transmission speech signal, relating to the transmission sound supplied to a microphone (46). The adder produces a particular calculation result signal representative of a result of the particular calculation. In accordance with the particular calculation result signal, a transmission is carried out towards the counterpart section.
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