Accession Number:

ADA018460

Title:

Near-Field Calibration of Underwater Electroacoustic Transducers.

Descriptive Note:

Technical memo.,

Corporate Author:

PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB

Personal Author(s):

Report Date:

1975-09-16

Pagination or Media Count:

128.0

Abstract:

A near-field acoustic measurement technique which provides the basis for accurately computing the far-field radiation characteristics of underwater sound transducers is developed, implemented and evaluated. The analysis is based on evaluating a form of the Helmholtz integral which utilizes a Greens function with particular boundary conditions for the solution. That is, the Greens function vanishes over the surface of integration, thereby requiring only knowledge of the near-field acoustic pressure for computing the far-field radiation. An experimental program is conducted to provide corroboration of the near-field technique. Design and construction details of the completely automated near-field measurement system, including the near-field acoustic sensors, the pulsed Amplitude-Phase electronic measurement system, and the Digital Scanner System are presented. Appropriate supporting software, in the form of a digital computer program, is provided for performing the data preparation and final far-field computations. Results of conventional far-field acoustic measurements at various frequencies on four different types of test transducers are presented.

Subject Categories:

  • Acoustic Detection and Detectors
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE