Accession Number : ADD017767

Title :   Active Acoustic Impedance Modification Arrangement for Controlling Sound Interaction.

Descriptive Note : Patent, Filed 1 Jul 91, patented 19 Sep 95,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Corsaro, Robert D

Report Date : 19 Sep 1995

Pagination or Media Count : 8

Abstract : An active impedance modification device or arrangement enables the interaction of sound with a structural surface to be controlled, e.g., so that, reflections from that surface (which can be the hull of a submarine) are substantially reduced or eliminated. The device comprises a coating comprising an inner driver transducer layer in contact with the structural surface an outer receiver transducer layer which receives the sound, in combination with a variable gain, variable phase shift amplifier connected between the interface of the outer layer with the sound carrying medium (e.g., water) and the interface between the second layer and the structural surface. Reflections are reduced by setting the gain and phase shift of the amplifier to simulate the input impedance of the sound carrying medium.

Descriptors :   *PATENTS, *ACOUSTIC COUNTERMEASURES, *ANTISONAR COATINGS, SETTING(ADJUSTING), LAYERS, MODIFICATION, STRUCTURAL PROPERTIES, REDUCTION, GAIN, TRANSDUCERS, SONAR RECEIVERS, AMPLIFIERS, ACOUSTIC IMPEDANCE, PHASE SHIFT

Subject Categories : Acoustic Countermeasures

Distribution Statement : APPROVED FOR PUBLIC RELEASE