Accession Number : ADD010407

Title :   Optimum Flow Noise Cancelling Hydrophone Module.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Fay,John W

Report Date : 14 Jun 1983

Pagination or Media Count : 6

Abstract : An apparatus for rejection of turbulence induced flow noise for towed hydrophone arrays. Two adjacent hydrophones in the array are spaced less than flow noise coherence distance apart forming a flow noise cancelling module. The inverted acoustic/flow noise signal from the lead hydrophone of the pair is split, one side passing to the final stage of signal processing while the other side, filtered, amplified and inverted, is added to the combined signal from the lag hydrophone which has been filtered and amplified. The acoustic signal components cancel leaving only the lead hydrophone flow noise plus the lag hydrophone flow noise which has been shifted by a factor dependent upon tow vessel speed and hydrophone spacing.

Descriptors :   *Patents, *Hydrophones, *Towed arrays, *Flow noise, *Noise reduction, Sonar sound analyzers, Low pass filters, Signal processing, Amplifiers, Inverter circuits, Acoustic signals, Circuit analysis, Range(Distance), Modular construction, Turbulence, Splitting, Coherence, Parts, Noise, Feedback, Delay, Cancellation

Subject Categories : Electrical and Electronic Equipment
      Acoustic Detection and Detectors
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE