基于激光干涉仪的微弱声信号检测方法研究

发布时间：2018-12-20 14:15

【摘要】：拾振器和水听器是声信号探测领域的主要工具。但其灵敏度较低,不能有效探测到微弱低频的声信号。但是利用现代的激光测量技术,例如激光干涉仪,就可以检测低频微弱声信号。本文对激光干涉测量技术进行了相关理论推导和实验验证。首先,本文简明扼要地介绍了几种激光测量技术的原理,以及国内外不同类型的激光测量设备,同时列举了其各自的特点和参数。其次,本文研究了几种光学计算方法,特别是用来计算干涉现象的琼斯矩阵法。在此基础上利用琼斯矩阵对偏振型干涉仪进行了理论推导。同时对激光干涉仪的调制解调算法进行了研究,对PGC算法中的有关参数进行了讨论和研究。再次,根据实际情况,设计制作了一套干涉测量系统,并对光学器件的材料和相关参数进行研究。根据设计指标要求,对压电陶瓷PZT及其放大电路和光电探测器的参数和性能进行了研究,并且设计了后续的采集传输以及后处理系统。最后,对激光干涉仪的主要光学元件的性能进行测试。利用加速度计和纳米位移台对干涉仪进行校验,验证其测量精度和频率准确性。最后分析了测量结果中的噪声情况,并找出测量过程中的干扰源。提出了后续改进设想。本文研究了激光干涉仪理论计算方法、信号调制解调方法,整套测量设备的设计方法。构建了一整套激光干涉测量系统,经测试可以在实验室,水池以及外场进行低频声信号探测。干涉仪能够探测到低频弱声声信号,分辨率和动态范围达到设计要求,整套系统工作稳定。
[Abstract]:Vibration pickups and hydrophones are the main tools in the field of acoustic signal detection. But its sensitivity is low, it can not detect weak low frequency sound signal effectively. But using modern laser measurement techniques, such as laser interferometers, low-frequency weak acoustic signals can be detected. The related theoretical derivation and experimental verification of laser interferometry technology are presented in this paper. Firstly, the principle of several laser measuring techniques and different kinds of laser measuring equipments at home and abroad are briefly introduced in this paper, and their respective characteristics and parameters are also listed. Secondly, several optical methods are studied, especially the Jones matrix method, which is used to calculate the interference phenomena. On this basis, the polarization interferometer is derived theoretically by Jones matrix. At the same time, the modulation and demodulation algorithm of laser interferometer is studied, and the related parameters in PGC algorithm are discussed and studied. Thirdly, according to the actual situation, a set of interferometric measurement system is designed, and the materials and related parameters of optical devices are studied. According to the design requirements, the parameters and performance of piezoelectric ceramic PZT and its amplifying circuit and photodetector are studied, and the subsequent acquisition, transmission and post-processing system are designed. Finally, the performance of the main optical components of the laser interferometer is tested. The interferometer is calibrated with accelerometer and nanometer displacement table to verify the accuracy of measurement and frequency. Finally, the noise in the measurement results is analyzed, and the interference sources in the measurement process are found out. The idea of further improvement is put forward. In this paper, the theoretical calculation method, signal modulation and demodulation method of laser interferometer and the design method of the whole measuring equipment are studied. A set of laser interferometry system is constructed, which can detect low frequency acoustic signal in laboratory, pool and field. The interferometer can detect low frequency weak sound signal, the resolution and dynamic range meet the design requirements, and the whole system works stably.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH744.3;TN911.23

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