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:
Jun. 17, 2003
Filed:
Oct. 14, 1999
Zhao Li, Austin, TX (US);
John E. Lane, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An echo canceller ( ) for a full-duplex communication system ( ) such as a speakerphone determines a gain factor to be used in sub-band adapter coefficient updates by using both time domain and sub-band signals to determine the state of the system ( ). In one embodiment a gain factor controller ( ) uses the sampled time domain signal to determine if the system ( ) is in the silence state, and if not uses the sub-band signals to determine whether the system ( ) is in the talk, double-talk, or listen state. The gain factor controller ( ) selectively changes the gain factor and selectively performs coefficient updating based on the state. In another embodiment the gain factor controller ( ) determines the state and selectively updates coefficients using state information developed on a band-by-band basis.