ECHO CANCELLER USING DELTA MODULATION

37 An echo canceller designed to cancel an echo signal ¢g(t)! generated in a send path (7) by a signal ¢f/(t)! applied to a receive path (1) contains a subtractor (9) whose positive terminal receives a signal derived from the echo signal and whose negative terminal receives the output signal from a...

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Bibliographic Details
Main Author FERRIEU, GILBERT M.M
Format Patent
LanguageEnglish
French
Published 04.04.1989
Edition4
Subjects
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
TRANSMISSION
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Summary:37 An echo canceller designed to cancel an echo signal ¢g(t)! generated in a send path (7) by a signal ¢f/(t)! applied to a receive path (1) contains a subtractor (9) whose positive terminal receives a signal derived from the echo signal and whose negative terminal receives the output signal from a transversal filter (10) provided with means (12) for adjusting the filter coefficients in such a way that the component due to the echo signal is cancelled at the output of the subtractor (9). This echo canceller comprises a delta encoder (14) for encoding at a sampling rate 1/T the signal f(t) entering the receive path (1) and for supplying at the input of the transversal filter (10) a delta-encoded signal (.DELTA.Fn), a circuit (22) for forming at the sampling rate 1/T the difference signal (dn) between two consecutive samples of the signal entering the send path (7) and for applying this signal to the positive terminal of the subtractor (9), and finally an integrator (13) connected to the output of the subtractor (9) and supplying the output signal of the send path (7).
Bibliography:Application Number: CA19850488720