Noise control composite
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsEugene C. Fischer, Jean A. Montemarano, Vincent J. Castelli, Joseph W. Dickey
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Abstract
A composite for use on submarines and surface craft for controlling self-erated noise when listening with sonar. The composite includes two layers of PVF.sub.2 transducers separated by a layer of phase shifting or absorbing material. The inner transducer senses noise from the ship and subtracts this from the signal from the outer transducer representing noise plus the desired signal. In a second mode the sensed noise is regenerated through the outer transducer 180.degree. out of phase to cancel the noise and allow more accurate detection.
Claims10
A composite material for use in a sonar device comprising:
- a first neoprene accoustic insulator layer placed on a solid substrate;
- a plurality of layers including alternating transducer layers and sound absorbing layers;
- a second neoprene accoustic insulator layer on top of said plurality of layers;
- and
- an antifouling layer including an elastomeric rubber containing an organometallic polymer.
A composite material for use in a shipborad sonar device comprising:
- at least one first transducer layer;
- at least one second transducer layer outside of said first transducer layer;
- at least one layer of anechoic material between said first and second transducer layers for accoustically insulating said first and second transducer layers from each other;
- at least one first lead, each of said first leads being connected to one of said first transducer layers;
- at least one second lead, each of said second leads being connected to one of said second transducer layers;
- and
- a control circuit connected to said first and second leads for receiving signals from said first and second transducer layers and for processing said signals so as to cancel shipboard noise from an output signal.
A sonar device for a ship comprising:
- a plurality of tiles each producing a signal, arranged in an array, wherein each tile is made of a layered composite material including at least two transducer layers separated by a layer of accoustical absorbing material;
- and
- a control circuit for selectively activating some of the tiles in the array to achieve directionality and for canceling self-generated noise from said signal.
Dependencies are inferred from the claim text.