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. 10, 1995
Filed:
Dec. 22, 1993
Noise Cancellation Technologies, Inc., Linthicum, MD (US);
Abstract
An electronic muffling device is disclosed for suppressing the noise emitted by an outlet of an exhaust pipe of an engine. The device comprises a housing having an outlet and a plurality of audio transducers. The transducers supply anti-noise to cancel detected unwanted noise. A microphone appropriately positioned to detect residual noise is coupled to a cancellation signal generator, which controls the anti-noise generated by the transducers. Anti-noise and unwanted engine noise propagate through a front volume within the housing so that exhaust gases are transmitted through the housing, but engine noise is canceled before leaving the housing. Exhaust gas may be transmitted into the housing, or may be passed through the housing without leaving the exhaust pipe. In either embodiment, engine noise enters the front volume and is canceled.