Accession Number : ADD018100

Title :   Towed Array Strain-Sensing Noise Canceller.

Descriptive Note : Patent, Filed 9 Sep 81, patented 2 Jul 96,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Hansen, Robert J ; Ni, Chen C ; Fitzpatrick, Hugh M

Report Date : Jul 1996

Pagination or Media Count : 5

Abstract : 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.

Descriptors :   *HYDROPHONES, *UNDERWATER ACOUSTICS, *PATENTS, FIBER OPTICS, OUTPUT, WATER, TOWED ARRAYS, STRAIN(MECHANICS), OPTICAL INTERFEROMETERS, SIGNALS, ACOUSTIC ARRAYS, WALLS, NOISE, RESPIRATION, WAVES, CURRENTS, HOUSING(DWELLINGS), PHASE SHIFT, RADIAL STRESS, HOSES

Subject Categories : Acoustics
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE