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:
Dec. 06, 2011
Filed:
Oct. 23, 2007
Takashi Ishiguro, Saitama, JP;
Koichi Kihara, Chiba, JP;
Yuzuru Masuya, Kanagawa, JP;
Junji Arai, Gunma, JP;
Takashi Ishiguro, Saitama, JP;
Koichi Kihara, Chiba, JP;
Yuzuru Masuya, Kanagawa, JP;
Junji Arai, Gunma, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
An echo canceler has an adaptive filter that generates an echo replica signal from a far-end signal. The filter coefficients of the adaptive filter are updated according to a residual error signal, which is obtained by subtracting the echo replica signal from a near-end signal to cancel echo. A background noise estimator estimates the near-end background noise power level from the residual error signal. A step size calculator uses the estimated near-end background noise power in determining the step size of the adaptive updating of the filter coefficients. When the estimated near-end background noise level is high, a small step size is used, which improves echo cancellation under these conditions. When the estimated near-end background noise level is low, a larger step size is used to permit rapid convergence of the filter coefficients.