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. 05, 1995
Filed:
Apr. 28, 1994
Fuji Jukogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A primary source is synthesized with a filter coefficient of a first adaptive filter into a canceling signal. The canceling signal is converted into a canceling sound and the canceling sound is generated from a speaker. A result of interference of the canceling sound with a noise sound is detected by a microphone as an error signal. The error signal is subjected to a sum of convolution products with the filter coefficient of the first adaptive filter in a LMS calculation circuit and the filter coefficient is updated therein. On the other hand, the error signal is subjected to a sum of convolution products with the canceling signal in another LMS calculation circuit and a filter coefficient of a second adaptive filter is updated. The updated filter coefficient of the second adaptive filter is sent to a compensation coefficient synthesizing circuit and therein the compensation coefficient is corrected by the filter coefficient. The corrected compensation coefficient updates the filter coefficient of the first adaptive filter. As a result, the first adaptive filter is automatically adjusted so as to reflect actual transmission characteristics in the passenger compartment, whereby a noise reduction with a stable performance is always obtained under any conditions of the passenger compartment.