The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 16, 1997
Filed:
Mar. 20, 1995
Toshio Yoshida, Tokyo, JP;
Michitaka Sisido, Tokyo, JP;
NEC Corporation, Tokyo, JP;
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.