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:
Apr. 20, 1999
Filed:
May. 24, 1996
William Chunhung Yip, Scottsdale, AZ (US);
Thomas Nall, Crystal Lake, IL (US);
Thomas Gerard Callaghan, Phoenix, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A two-wire line and a four-wire line telephone system interface with each other through a hybrid (12). After a connection between the two and four-wire line systems is made, an echo canceler (10) provides training signals to the hybrid on the transmit path an generates echo cancellation signals on the receive path. An adaptive filter (16) is employed to provide the proper echo cancellation signals, while a controller (22) provides filter coefficients based on an error signal. The training signals include the convolution of an impulse function with a sin(x)/x function. Once the filter coefficients are determined for the particular call, the transmit path of the four-wire line system is switched in and voice data between the two systems my commence.