Broadband calibration method for sensitivity free field of hydrophone based on pink noise

Abstract

The present invention discloses a broadband calibration method for sensitivity free field of a hydrophone based on pink noise. The calibration method relates to the field of free-field underwater acoustic measurement and is mainly used for broadband measurement of hydrophone free field sensitivity. According to the method of the invention, a signal source is controlled to transmit a broadband pinknoise signal; a transmitted current signal and a received voltage signal are subjected to synchronous treatment such as interception and zero padding and FFT transformation; finally a transfer function in the frequency domain is obtained. By analyzing the direct wave and reflected wave of a tank, the transfer function is subjected to moving average with a rectangular window; the reverberation influence of the reflected wave of the tank is eliminated; a broadband transfer function of the free field between a transmitting transducer and the hydrophone is obtained; and the broadband measurementfor hydroacoustic parameters such as hydrophone sensitivity is realized. The method can be used for broadband calibration of the hydrophone in an anechoic tank, a reverberant tank, an outfield lake and sea.

Description

Technical field [0001] The invention belongs to the technical field of underwater acoustic measurement, and specifically relates to a pink noise-based hydrophone sensitivity free-field wideband calibration method. Background technique [0002] With the development of hydroacoustic technology, hydroacoustic measurement plays an important role in ensuring the performance indicators and normal use of hydroacoustic equipment. The free field is the sound field closest to the actual working environment of hydroacoustic equipment such as transducers and hydrophones. Therefore, the study of free field calibration plays an important role in ensuring the development and practical application of hydroacoustic transducers and hydrophones. [0003] For a long time, the pulse acoustic technology has been the most commonly used technical method in the measurement of underwater electroacoustic parameters. This method can separate the direct signal and the reflected signal in time by emitting a sin...

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Problems solved by technology

[0003] For a long time, pulse acoustic technology has been the most commonly used technical method in the measurement of underwater electroacoustic parameters. This method can separate the direct signal and the reflected signal in time by transmitting a single-frequency pulse signal with a limited period, so as to reduce the boundary of the pool. However, this method still has certain limitations: (1) Impulse acoustic technology mainly transmits a certain period of filling wave short pulse signal, and uses the time delay of the direct sound and the reflected sound to combine the direct sound in the time domain The wave and the reflected wave are separated, but as the measurement frequency decreases, the wavelength of the sound wave becomes longer, making the duration of the pulse wave of a certain period longer in the time domain, and the reflected sound will be superimposed on the direct sound, resulting in the inability to measure in time (2) As the measurement frequency decreases, the sound absorption effect of the sound-absorbing wedge in the anechoic pool becomes worse, and the reflected wave in the anechoic pool has a greater impact on the measurement; (3) Impulse acoustic technology can usually only complete single-frequency measurement, while underwater acoustic equipment such as transducers and hydrophones usually work in noise signals or continuous signals in actual measurement, and their broadband frequency response needs to be known. Therefore, the current impulsive acoustic technology cannot meet the wideband measurement of transducers and hydrophones

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