Method and circuit arrangement for detecting speech in a telephone terminal from a remote speaker

U.S. Patent Number: 5818928

Abstract: In communication networks with transmission devices using analog circuitry, because of unadapted 4-wire/2-wire junctions, some of the speech of a local speaker is reflected back to the local speaker as a line echo. This line echo is neutralized by echo compensators. However, updating of the filter coefficients of the echo compensators cannot be allowed to occur unless speech of the far-end speaker is absent. Thus, recalculation of the filter coefficients must be precluded at other times. Various possibilities for detecting the speech of a local speaker are well known. According to the invention, detection of the speech of a far-end speaker is fed back to obtain an attenuation measurement of the transmission path; this received speech simulates a reduction in attenuation. From the difference between the long-time average (Aa(k+1)) and the short-time average (A(k+1)) of the attenuation, it is learned very quickly, by comparison with a threshold (THRe), whether speech is present or not. The method is also applicable in order to discontinue automatic voice output on the local end by means of duplex voice communication.

Inventors: Rozinaj; Gregor (Stuttgart, DE), Fesseler; Peter (Stuttgart, DE)

Assignee: Alcatel N.V. (Rijswijk, NL)

Application Number: 08/724,795

Issued: 1998-10-06

Expired: 2006-10-06

Classes: 379/406.07 ; 379/444; 381/66; 704/228

Field of search: 704/215,226,227,228,233,234,248,253 379/406,410,414,444,411 381/66

Click the image above to view patent images at uspto.gov within a frame.

Click here for the fulltext page on uspto.gov within a frame.