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:
Jul. 02, 1991
Filed:
Sep. 29, 1989
Katsuyoshi Nagayasu, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A noise cancellor includes a first sensor for detecting a noise generated from a driving device and converting the noise to electric signals. A signal processor receives the electric signals and forms control signals by multiplying the electric signals by a predetermined factor series. In response to the control signals, a speaker produces sound which interferes with the noise so as to cancel the noise at an object point. A second sensor detects sound at the object point and converts them to electric signals which are inputted to the signal processor. The signal processor switches the control mode, in accordance with a predetermined condition, to an adaptive active control wherein the factor series is changed in response to the electric signal applied from the second sensor or an active control wherein the factor series is fixed.