聚焦参量阵原频声场抑制方法的研究  

Research on primary frequency sound field suppression methods of focused parametric array

作　　者：夏靖杰 冯海泓[1] 黄敏燕[1] 洪峰[1] XIA Jingjie;FENG Haihong;HUANG Minyan;HONG Feng(Shanghai Acoustic Laboratory,Chinese Academy of Sciences,Shanghai 201815,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院声学研究所东海研究站,上海201815 [2]中国科学院大学,北京100190

出　　处：《声学技术》2022年第1期28-34,共7页Technical Acoustics

基　　金：国家重点研发计划项目(2016YFC0302000);国家自然科学基金青年科学基金项(61801471);国家大洋专项项目(DY135-C1-108)资助项目。

摘　　要：在近距离海底底质原位探测中,使用多阵元聚焦技术能弥补参量阵中差频信号能量较低的不足,但也会使得声焦点处的原频信号能量过高,导致接收系统信号波形限幅,引起波形失真,此外在声场测量时也容易造成传感器损坏。基于KZK(Khokhlov-Zabolotskaya-Kuznetsov)方程和Berktay包络自解调理论,以声焦点位于阵元差频声场远场、各阵元产生非线性效应的过程相对独立的双阵元聚焦参量阵为例,提出了一种在不破坏差频声场特性的前提下,改变发射信号形式以抑制原频声场的方法。结果表明:与发射相同载波相位的幅度调制信号相比,当两个阵元发射信号的载波相位相反时,声轴上的原频信号能量得到了明显抑制,实测声焦点处的原频声压级下降了13.2 dB,而差频声场未发生明显变化,从而验证了抑制方法的可行性。In the offshore seafloor in-situ detection,the use of multi-array focused technology can compensate for the inherent deficiency of the acoustic parametric array to produce a strong difference frequency energy,but the high energy of the primary frequency signal at the acoustic focal point can lead to amplitude clipping in the receiving system,which causes waveform distortion.Transducers are also susceptible to damage during sound field measurements.In this paper,a dual-element focused parametric array with its acoustic focus located in the far difference-frequency sound field is taken as a research object.Based on KZK(Khokhlov-Zabolotskaya-Kuznetsov)equation and Berktay’s envelope self demodulation theory,the way to suppress the primary frequency sound field by changing the transmitting signal without affecting the difference frequency sound field is proposed.The results show that,in contrast to the case where two arrays emit amplitude modulated signals in the same phase,when the two emitting signals are in opposite phases,the primary frequency sound pressure level(SPL)decreases along the acoustic axis with a 13.2 dB reduction at the acoustic focal point,while the difference frequency sound field remains unchanged.

关 键 词：聚焦参量阵 原频声场抑制 Berktay包络自解调理论 KZK方程参量阵 

分 类 号：TB566[交通运输工程—水声工程]