研究了半导体激光自混合干涉测振仪的调制与解调技术。设计了基于电流调制和DSP解调的半导体激光自混合干涉测量系统,实现对振动物体的非接触式测量。分析了激光自混合干涉测振仪的理论模型,并用Matlab进行了仿真和误差分析。研究了系统的调制解调技术及基于DSP的数据采集与处理系统。该系统体积小、成本低、易于准直。提出的测振仪能够测量振动频率在5 kHz内的物体振动频率、振幅及振动波形,振动幅度测量精度可达0.325 μm。

The modulation and demodulation technology of semiconductor laser self-mixing interference vibrometer is researched. With triangular wave modulation and DSP demodulation technology of self-mixing interference,a new type vibrometer is designed to achieve non-contact vibration measurement of a target. The theoretical model of the laser self-mixing interference vibrometer is analyzed and simulation and measurement error analysis are done using matlab. The modulation and demodulation technology of the vibrometer system and DSP-based data acquisition and processing system are researched. The vibrometer is small-sized,low-cost and easy to collimate,and can measure the object whose vibration frequency range arrives 5 kHz,and the vibration scope measuring accuracy may achieve 0.325 μm. The instrument can measure the vibration frequency and amplitude data of the vibration object and restore the vibration wave.