Wideband beam pattern

Abstract

Transducer directivity is important in the basic acoustic surveying methods of echo counting and integration. In quantifying the directivity, the beam pattern is often computed assuming ideal single-frequency operation. The validity of this for typical pulsed signals and receivers is examined. A wideband beam pattern is defined and computed for several different combinations of transducer geometry, transmit pulse duration, and receiver frequency response function. For each, the directivity index and equivalent beam angle are computed and compared with the respective single-frequency estimates.