Testable echo cancelling method and device

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United States of America Patent

PATENT NO 5008923
SERIAL NO

07509797

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Abstract

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A communications system adaptive echo canceller integrally contains a test far-end talker signal generator, an echo signal generator for generating an echo signal with a simulated echo path, a residual echo detector for detecting a residual echo based on the output of a subtracter, and a switching unit for switching an input and output signal of the echo canceller into an echo canceller test mode. Further, it provides a bypassing unit for, in a test mode, separating a call/talk connected to the echo cancellers from the echo cancellers and forming a bypass path between trunk circuits and a transmission circuit. The bypassing unit results in being able to realize a test for the echo canceller while a talk is alive.

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Patent Owner(s)

Patent OwnerAddress
HITACHI LTD A CORP OF JAPAN6 KANDA SURUGADAI 4-CHOME CHIYODA-KU TOKYO

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Kitamura, Youichi Yokohama, JP 3 32
Tajimi, Michiko Yokohama, JP 1 30

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