Signal Enhancement of Specularly Scattered Underwater Sound.

Abstract

The aim of this work is to show that the fluctuations of sound caused by surface specular scattering are to some extent predictable. Thus the energy associated with these signals, normally discarded, can be utilized. The wind driven surface of a model ocean was used to study the simultaneous amplitude fluctuations of 31 specularly scattered harmonic components from 5 kHz - 160 kHz. The temporal variations of the scattered components show maxima and minima whose anticorrelation depends on the sound frequency ratio. Significant signal enhancement can be obtained through timely frequency switching between a base frequency and its second harmonic. This gain is found to depend on the effective surface roughness, the duration of the experiment, and the switching threshold.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1977
Accession Number
ADA050277

Entities

People

  • Robert Bishop Shields Jr

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Waves
  • Acoustics
  • Acquisition
  • Angle Of Incidence
  • Chemistry
  • Computer Programs
  • Computers
  • Data Acquisition
  • Databases
  • Frequency
  • Geometry
  • Research Facilities
  • Scattering
  • Statistical Analysis
  • Surface Roughness
  • Underwater Sound
  • United States

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Electrical Engineering
  • Thin Film Deposition Science.