Equivalent size and acoustic center of measuring hydrophone

Abstract

The problem that arises during the amplitude-phase calibration of hydrophones by the reciprocity method and consists in the violation of the consistency of the hydrophone characteristics specified by the manufacturer is considered. Violation of the indicated consistency of characteristics is due to the need to determine the phase-frequency characteristic when calibrating the hydrophone. The manufacturer sets the dimensions of the receiving part of the hydrophone and the position of the acoustic center according to the drawing of the receiving part and, thereby, replaces the acoustic parameters with geometric ones. To restore the consistency of the characteristics, it is proposed to determine the position of the acoustic center and the equivalent size of the receiving part of the hydrophone from the results of acoustic measurements. It is shown that the displacement of the acoustic center of a hydrophone relative to its geometric center is a characteristic phenomenon, while the geometric and acoustically measured dimensions of the active element may differ. To ensure the unity of acoustic measurements, it is proposed to introduce the concept of an equivalent radius and to clarify the concept of the acoustic center of a hydrophone, as well as to standardize the methods of their experimental determination. The results obtained will be useful in monitoring the phase responses of elements of hydroacoustic antennas for various purposes, ensuring the identity of the phase-frequency characteristics of the vector receivers measuring channels, in solving problems related to restoring the shape of an acoustic signal from the recorded output receiver voltage, for various applications, including marine ecology, medical ultrasound, etc.