Towed Array Strain-Sensing Noise Canceller.
Patent, Filed 9 Sep 81, patented 2 Jul 96,
DEPARTMENT OF THE NAVY WASHINGTON DC
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Method and apparatus are disclosed for reducing breathing- wave induced noise in a liquid-tilled elongate hose housing a hydrophone array. The arrangement involves sensing radial strain induced in the hose wall by the breathing waves created as the hose is drawn longitudinally through water and subtracting a multiple of the sensed value thereof from the array hydrophone output. Arrangements for measuring the breathing-wave-induced wall strains include 1 relative phase shifts in light passing through the sensing arm of an optical fiber interferometer, and 2 signal currents generated from piezolectric polymer both of which are disposed inside the hose wall surrounding a hydrophone.
- Marine Engineering