Russell N Thomas

US Patent:

56621361, Sep 2, 1997

Filed:

Sep 11, 1995

Appl. No.:

8/498489

Inventors:

Tadeusz M. Drzewiecki - Rockville MD
John B. Niemczuk - Kensington MD
Christopher R. Fuller - Norfolk VA
Russell H. Thomas - Hampton VA
Ricardo A. Burdisso - Blacksburg VA

Assignee:

Defense Research Technologies, Inc. - Rockville MD
Virginia Tech Intellectual Properties, Inc. - Blacksburg VA

International Classification:

F15C 104
F15C 112

US Classification:

137 14

Abstract:

Reduction or cancellation of acoustic noise is achieved by providing an amplified, oppositely phased version of the noise by means of an acousto-fluidic amplifier. The amplified acoustic output noise is delivered through an impedance matching horn in destructively interfering relation with the original noise. Depending on the acoustic noise source and its spatial distribution, the acousto-fluidic amplifier may be a single stage amplifier or multiple stages connected in parallel and/or cascade, with output horns spatially distributed to have the maximum cancellation effect. Sensed noise, prior to fluidic amplification, may be processed in a manner to effect feedback or feedforward control of the amplified acoustic output signals.

Author:

Russell J. Thomas

ISBN #:

0198559437

Author:

Russell J. Thomas

ISBN #:

0198559445