Experimental Data on Dynamic Changes of Radio Pulses When They are Emitted by Piezoceramic Electromechanical Transducers

Abstract

The article discusses the issue of distortion of acoustic signals emitted by piezoelectric transducers in relation to electrical excitation signals. It has been shown experimentally that in acoustic locating systems, exciting electrical pulse signals differ significantly from the acoustic pulses emitted by them. The study was carried out on a cylindrical piezoceramic transducer. The reason for these differences is the presence of piezoceramic electromechanical transducers in radar systems. Their resonant oscillatory systems are formed by two circuits, electrical and mechanical, interconnected by an ideal electromechanical transformer. The physical properties of these contours differ significantly in their purposes and properties. The electrical circuit of the converter is involved only in the conversion of energy, and its mechanical circuit is involved both in the conversion of energy and in its formation in the environment. The main difference in the properties of the circuits is the significant inertia of the mechanical circuit as a mechanical resonant oscillatory system and the inertia of the medium loading it when sound is emitted. This explains the occurrence of transient processes during the formation of acoustic pulses and their absence during the formation of electrical pulses. The distortions of acoustic pulses caused by transient processes have been experimentally established. They consist of a smooth rise of the leading edge of the acoustic pulse and the decay of its rear front, as well as the appearance at the beginning and at the end of short, sharp "bursts" of acoustic pressure amplitudes. It is shown that the magnitude and nature of the manifestation of dynamic distortions of acoustic pulses depend on the ratio of frequencies of harmonic filling of electrical pulses and the frequency of mechanical resonance of a piezoceramic electromechanical transducer. Filling frequencies of 3.5, 7 and 10 kHz were investigated, which correspond to frequencies below the mechanical resonance of the transducer, the resonance frequency, and frequencies above the mechanical resonance. It is concluded that it is necessary to assess the resolution of acoustic locating devices based on their acoustic pulses of radiation and reception.