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:
May. 17, 1994
Filed:
Jun. 15, 1992
Applicant:
Inventor:
Hideo Sano, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B / ;
U.S. Cl.
CPC ...
375103 ; 375102 ; 370 321 ; 379410 ;
Abstract
In order to reduce the complexity of an adaptive digital filter used to cancel delayed network echoes, a delay circuit is arranged in series therewith and arranged to compensate for the delay inherent with a speech codec. In the case of a variable delay circuit, the degree by which the echo is delayed is detected in the adaptive digital filter and used to modify the delay time. A gain control arrangement can be provided and used to reduce the gain of the received signal when the near-end party is talking and the adaptive capacity of the adaptive digital filter is exceeded.