Method for measuring difference-frequency wave space distribution characteristics in parameter sound field

Abstract

The invention provides a method for measuring difference-frequency wave space distribution characteristics in a parameter sound field. Firstly, the parameter sound field is composed of two lines of high-frequency sound waves f1 and f2, an active area of the parameter sound field is measured, the parameter sound field is uniformly divided into n measuring grids, a difference-frequency wave amplitude value is measured on any one grid point A, then a low-frequency sound wave f3 is independently emitted, and the amplitude value of the sound wave at the point A is equal to the difference-frequency wave amplitude value; finally, the three lines of sound waves f1, f2 and f3 are emitted simultaneously, a power spectrum is obtained, and the phase position of a difference-frequency wave at the point can be obtained according to the f1 initial phase position corresponding to the minimum value of the power spectrum; the steps are repeated to measure the difference-frequency wave amplitude of other points and phase position information. According to the method, the distribution characteristics of the difference-frequency wave amplitude and the phase positions in the parameter sound field are described simultaneously, the problem that a difference-frequency wave phase position changing rule in the underwater parameter sound field is difficult to describe in an existing experimental method and an engineering technology is resolved, and a basis is laid for analyzing the characteristic of the sound parameter field.

Description

technical field [0001] The invention relates to an experimental method for measuring the spatial distribution characteristics of difference frequency waves in a parametric sound field by using three-wave acoustic interaction in the field of nonlinear acoustics. Background technique [0002] When two columns of large-amplitude sound waves propagate in the medium, sound waves of other frequencies will be generated, including double frequency, sum frequency and difference frequency, etc. Among them, the difference frequency wave is the most widely used. As we all know, the acoustic parametric array is one of the important applications in the field of nonlinear acoustics. Ultrasound imaging, etc. It refers to the use of acoustic wave interaction to generate difference frequency waves to obtain low-frequency beams under the condition of small array size. Due to sharp directivity and wide frequency bandwidth, it can improve spatial resolution, anti-reverberation and obtain higher...

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Problems solved by technology

However, the above literature only gives the method of calculating the amplitude of the difference frequency wave, and does not involve the method of extracting the phase of the difference frequency wave

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