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. 09, 1996
Filed:
Dec. 28, 1993
Susumu Saruta, Hirakata, JP;
Yasuyuki Sekiguchi, Takatsuki, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An active noise attenuating device applied to a draft duct of an air condition system including a microphone disposed in a propagation path of noise for detecting the noise, a loud speaker disposed in the noise propagation path, a control circuit for producing a control signal on the basis of the detection signal from the microphone, the control signal being supplied to the loud speaker so that the speaker produces an interference sound having the same amplitude as of the noise detected by the microphone and a phase opposite to the noise, at a control point in the noise propagation path, and a high pass filter for damping or cutting off a frequency component contained in the control signal and belonging to a low frequency range in which the loud speaker is unable to reproduce the interference sound.