一种时域解调激光干涉仪调制信号的方法

针对某低频水平振动校准设备的激光干涉仪,利用NI公司的多功能采集卡,采集激光干涉仪的调制信号及与其同相位的电容式位移传感器的输出信号.根据激光干涉仪调制原理,提出一种时域解调调制信号的方法.根据调制信号条纹的时域特性和它被限幅的实际特点,利用labview软件实现了信号的解调,并将电容位移传感器信号作为参考信号,还原解调后信号的相位,从而得到振动台高精度的振动波形.实验证明,此方法对连续振动信号的解调效果良好,具有较好的重复性和稳定性,精度可达到激光干涉仪发射激光波长的四分之一.

Demodulate modulation signal of laser interferometer in time domain

In this paper, aimed to a laser interferometer of a low frequency vibration calibrated device, its modulated signal and the capacitance displacement transducer signal are collected together through multifunction I/O board. Based on the modulation theory of laser interferometer and the time domain characteristics of modulated signal stripe, a new demodulate method in time domain is proposed. The phase of demodulated signal is corrected by analyzing the displacement transducer signal. By demodulating lots of experimental datum, this method is commendably effective to demodulate consecutive signal, and has preferably repetition and stability. The precision reaches quarter of the laser wavelength.