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:
Mar. 13, 1979
Filed:
Nov. 18, 1977
Shintaro Oshima, Musashino, JP;
Akira Sato, Tokyo, JP;
Abstract
An echo cancelling system, in which a pseudo-echo is provided by producing an impulse response of an echo path, reversed in phase and then applied to a subtractor of the echo path to cancel an echo. A low level reference signal, such as random noise or an artificial random signal, is continuously applied to the echo path and successively delayed by a sampling period to obtain a plurality of delayed reference signals, which are multplied by the output of the subtactor to obtain a plurality of multiplied outputs. The multiplied outputs are integrated by integrators and then amplified by high gain amplifiers to be employed for producing the psuedo-echo. As a result of such construction of the adaptive control loop, the convergence time for cancellation is effectively improved.