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:
Oct. 05, 1993
Filed:
Jun. 28, 1991
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An adaptive type active noise cancellation apparatus comprises a first sensor for detecting a noise generated by a noise source and outputting a detection signal, a filter having a predetermined filter coefficient and filtering the output signal from the first sensor by using the predetermined filter coefficient and outputting a filtered signal, a speaker for receiving the filtered signal and generating a sound corresponding to the filtered signal, an active noise cancellation control system for actively canceling a noise at a control target point by using the sound generated by the speaker, a second sensor, arranged at the control target point, for detecting a sound at the control target point and outputting a detection signal, and an adaptive control system for receiving the output signals from the first and second sensors and adaptively updating the filter coefficient in accordance with a change in state of a system to which the active noise cancellation control system is applied. The adaptive control system includes a switch for stopping the active noise cancellation control system in adaptive processing, and a correction system for correcting the output signal from the first sensor or the second sensor by using a transfer function corresponding to a delay in a spatial system between the speaker and the second sensor and a delay required for calculation processing.