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:
Aug. 29, 1989
Filed:
Nov. 16, 1987
Daniel S Hoefkens, Antwerp, BE;
Joannes H Spaenjers, Kalmthout, BE;
Eduard C Boeykens, Hingene, BE;
Henri A Verhille, Borgerhout, BE;
Gustaaf A Geernaert, Antwerpen, BE;
Alcatel N.V., Amsterdam, NL;
Abstract
An echo canceller determines the optimum value of the required digital filter coefficient from values obtained by measuring a plurality of samples of the echo signal and by measuring, for each of a predetermined number of such samples, the replica signal sample factors which, when multiplied by the filter coefficients and summed, cancel the echo signal sample. The echo signal samples as well as the factors used to determine the replica signal samples are both measured in a way that reflects the actual environment in which the echo canceller is used. To measure each of the factors of the replica signal sample corresponding to an echo signal sample, an input signal is applied to the receive path, the filter coefficient corresponding to the factor is set to a non-zero value and the other filter coefficients to zero, and the resultant replica signal sample is then measured. It is not necessary for the echo signal and replica signal measurement to be made concurrently, or from the same location.