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:
May. 02, 1989
Filed:
Aug. 09, 1985
Gilbert M Ferrieu, Bievres, FR;
Abstract
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.F.sub.n), a circuit (22) for forming at the sampling rate 1/T the difference signal (d.sub.n) 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).