Decreasing Pulse Duration at Receiver Output under Emitter Excitation with Complex Waveforms

Resumo

The pulsed operation mode of an emission–reception system consisting of two immersion piezoelectric transducers separated by a liquid (glycerine) layer has been studied. Identical piezoceramic plates were used as active elements in the emitter and receiver. The rear sides of the plates were loaded on air. The emitting transducer was excited by composite-waveform electric signals consisting of two sine-wave half-periods with different amplitudes (with their sign taken into account). The length of each half-period corresponded to the half-period of emitting plate vibration at the antiresonance frequency. The first half-period was the exciting one, with the second, supplied at the appropriate moment, being the compensating one. The amplitudes of the compensating half-periods were precalculated based on a mathematical algorithm developed by the authors in their previous works. It has been shown that applying composite-waveform signals allows one to considerably reduce the duration of a signal at the receiver output as compared with the case where the emitter is excited by an electric pulse in the form of one half-period of vibration at the antiresonance frequency. Experimental data are in fair agreement with computation results.