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:
Jun. 05, 1995
Filed:
Sep. 29, 1992
William G Culbreath, Henderson, NV (US);
Eric W Hendricks, San Diego, CA (US);
Robert J Hansen, State College, PA (US);
Abstract
An method and apparatus for active noise cancellation in a conduit carrying a liquid, employing a detector hydrophone, an acoustic canceler downstream of the detector hydrophone, an error hydrophone, and an adaptive filter. The outputs of the detector hydrophone, acoustic canceler, and error hydrophone are directed into the adaptive filter, which uses them to select the form of acoustic signal which the canceler directs into the liquid to cancel the noise. One embodiment of the invention employs two such cancellation circuits, and an additional adaptive filter which globally optimizes the cancellation of both circuits.