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. 23, 1995
Filed:
Apr. 16, 1992
Siemens Telecomunicazioni S.p.A., Milan, IT;
Abstract
A procedure and device are described for cancellation of the echo produced in telephone connections with electrical time-variant characteristics such as for example those affected by phase roll. The echo canceller obtained in accordance with the procedure which is the object of this invention produces an estimate of the echo signal by means of appropriate digital filtering of the signal originated by the far-end talker. The estimated echo is then subtracted from the actual echo. Filtering is activated by an IIR digital filter whose adaptive coefficients are updated by use of an adaptive algorithm based on decimation of the square error. The high convergence speed of said algorithm in the calculation of the coefficient correction step allows a correct estimate of the echo even in case of connections affected by phase roll.