DEVICE FOR ENHANCING THE CONVERGENCE OF AN ECHO CANCER OF A DIGITAL SPEECH SIGNAL.

摘要

The device comprises a digital computer (1) receiving on a plurality of input ports the transmitted peak envelope signals SEC1(n), SEC2(n), received peak envelope signals SRC(n) and peak envelope signals EC(n) restored by the echo canceller (2) and supplies to the self-adapting filter (FA) thereof the leakage CF(n) and control K(n) coefficient signals. Peak envelope detector circuits (3, 4, 6, 7) provide the said peak envelope signals. Filter coefficients (FA) are adjusted according to the law: ai(n+1) = ai(n) + K(n) . E(n). SE(n-2) +/- CF(n). The control coefficient K(n) ensures optimum convergence of filter (FA) according to a single or double voice communication distinction criterion corresponding to the absence or presence of simultaneity of transmitted or received SE(n) and SR(n) voice signals. Application to the transmission, in telephony, of digital or analog voice signals.