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:
Feb. 03, 2004
Filed:
Nov. 24, 2000
Heping Ding, Ottawa, CA;
Nortel Networks Limited, St. Laurent, CA;
Abstract
An adaptive filter having a hybrid structure and capable of operating in a tri-mode regime is disclosed. The tri-mode adaptive filter includes three sub-filters which operate in a fast convergence mode, a slow convergence mode, and a freezing mode respectively. The adaptive filter further comprises a quality detector which measures non-convergence and a near-end signal of the tri-mode filter and generates a feedback signal which is sent to a switching means. In response to the feedback signal, the switching means provides switching between the sub-filters so that one of the sub-filters operates at a time, providing adaptive filtering in accordance with its corresponding filtering method. In the embodiment of the invention the sub-filters operating in fast, slow and freezing mode are represented by Conjugate Gradient Fast Affine Projection (CGFAP) adaptive filter, Normalized Least Mean Square (NLMS) adaptive filter and Freezing adaptive filter respectively, wherein the Freezing filter operates with constant adaptive filter coefficients, i.e. without updating the filter coefficients, thereby providing convolution without adaptation. Corresponding method of adaptive filtering is also provided.