Digital System for the Measurement of Directivity Index

摘要

An experimental system has been devised for measuring the directivity index of an underwater sound transducer in about 10 minutes, which represents a substantial improvement over the conventional measurement time of at least one hour. This system is designed to measure sound intensity over equal areas of a spherical surface at a fixed radius from the transducer and to calculate directivity index by means of a minicomputer. A seven-element semicircular array of receiving hydrophones provides data for every 10 degrees of azimuth angle. Results of system measurements on several USRD transducers that were within the design limits of the array compared favorably with those obtained by conventional methods and by theoretical predictions. (Author)