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:
Feb. 21, 1995
Filed:
Nov. 01, 1993
Frederic G Pla, Schenectady, NY (US);
Harindra Rajivah, Clifton Park, NY (US);
Anthony A Renshaw, Albany, NY (US);
Robert A Hedeen, Clifton Park, NY (US);
General Electric Company, Schenectady, NY (US);
Abstract
A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency is tuned by adjusting the size of a frame which encloses the noise radiating element. One or more expandable elements are disposed in the frame to produce expansion and contraction of the frame. The elements are actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the elements and causes the frame to expand or contract.