Near-Field Calibration of Underwater Electroacoustic Transducers

Download or read book Near-Field Calibration of Underwater Electroacoustic Transducers written by Robert D. Marciniak and published by . This book was released on 1975 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.