Radiating Wideband Sonar Pulses with Resonant Sandwich Transducers by Designing the Driving Voltage Waveform

Abstract

A technique to radiate short length, high resolution, pulses with conventional piezoelectric transducers is described. It consists on designing the driving voltage waveform so that the radiated pulse has a zero-phase cosine-magnitude spectrum compatible with the natural frequency response of the transducer. According to Berkhout [1], zero-phase cosine-magnitude pulses have the minimum length, maximum resolution, within a prescribed frequency band. When applied to a 9 kHz sandwich transducer, this technique decreases the pulse length from 1 ms to 0.13 ms, increases the bandwidth from 1.4 kHz to 11.25 kHz, and lowers the Q factor from 6.2 to 1.23, at the cost of 33% of amplitude loss.