Wideband Pulse Generation for Underwater Applications Using Parametric Array

TL;DR

This paper demonstrates the design and testing of a parametric array transducer capable of generating short, high-frequency underwater acoustic pulses suitable for coded transmission, with potential applications in underwater communication and sensing.

Contribution

It introduces a novel underwater parametric array transducer that produces short, high-frequency pulses with high phase sensitivity and excellent burst definition.

Findings

Successful generation of very short bursts as short as half-cycle

High phase sensitivity enabling coded transmission

Excellent burst definition with normalized cross-correlation of 0.92

Abstract

We investigated wideband pulse generation for underwater acoustic applications using a parametric array. We fabricated a transducer consisting of a 3 mm thick 75 mm-by-75 mm square-shaped PZT ceramic plate, which is matched to water media at the radiating face and terminated by a very low impedance at the back. All measurements were made in a large test tank. We transmitted square-root amplitude modulated pulses centered around 855 kHz primary frequency. We showed that phase-sensitive generation of in-phase and out-of-phase bursts suitable for coded transmission using a parametric array is possible. We generated very short duration bursts, as short as half-cycle, at a 10-80 kHz difference frequency range. The definition of the bursts is excellent, e.g., with a normalized cross-correlation of 0.92 with an ideal 2-cycle square burst, for both in-phase and out-of-phase pulses.