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:
Jan. 25, 1977
Filed:
Sep. 04, 1975
Applicant:
Inventors:
Takashi Araseki, Tokyo, JA;
Kazuo Ochiai, Tokyo, JA;
Takashi Ogihara, Tokyo, JA;
Shunji Tanaka, Tokyo, JA;
Assignee:
Nippon Electric Company, Ltd., Tokyo, JA;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B / ;
U.S. Cl.
CPC ...
1791702 ; 1791706 ;
Abstract
An echo controller comprises a parallel circuit of an echo suppressor and a self-adaptive echo canceller near an echo path of a long-distance telephone network. The echo controller further comprises a mode switch responsive to levels of a received signal, an unprocessed signal, and an output signal of the echo canceller and operable during absence of double talk for suspending operation of the echo canceller and putting instead the echo suppressor into operation only when characteristics of the echo path and operation of the echo canceller are objectionable.