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:
Sep. 16, 1997
Filed:
Jan. 25, 1995
Tadashi Ohashi, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A coefficient updating method stops updating filter coefficients for a plurality of adaptive filters when a convergence condition is achieved. Active noise control within a system simulates an original noise signal with a simulated noise signal which is equal and opposite to the original noise signal. To detect feedback in such a system, a reference signal or 'white noise' is generated by a speaker, transmitted through the system and received by a microphone. Coefficients of multiple filters such as an anti-feedback filter, a C filter, and a noise control filter are then updated to minimize adverse parameters such as original noise and feedback. Coefficient updating of the adaptive filters is stopped when a minimum average value is reached.