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.

Date of Patent:
Sep. 03, 1996

Filed:

Dec. 16, 1994
Applicant:
Inventors:

Manpei Tamamura, Ohta, JP;

Hiroshi Iidaka, Tokyo, JP;

Eiji Shibata, Oura, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
A61F / ; H03B / ;
U.S. Cl.
CPC ...
381 71 ; 381 94 ;
Abstract

Pulses synchronized with the period of the noise are generated and inputted to the adaptive filter. On the other hand, the tap number of the delay line of the adaptive filter is terminated at a tap number which is equal to the interval of the inputted pulse, whereby the number of times for calculation at the adaptive filter can be substantially reduced. Furthermore, in case where the tap number of the adaptive filter is changed according to the change of the period of the noise sound, the filter coefficient for cutting the high frequency domain is convoluted into the tap value of the adaptive filter, whereby noises caused by the change of the tap number can be eliminated even when the tap number of the adaptive filter is changed.


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