Accession Number : ADA018460

Title :   Near-Field Calibration of Underwater Electroacoustic Transducers.

Descriptive Note : Technical memo.,


Personal Author(s) : Marciniak,Robert D.

Report Date : 16 SEP 1975

Pagination or Media Count : 128

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 Green's function with particular boundary conditions for the solution. That is, the Green's 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.

Descriptors :   *Electroacoustic transducers, *Acoustics, Near field, Calibration, Acoustic measurement, Underwater sound, Sound transmission, Underwater sound equipment, Theses, Far field

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE