一、引 言 激光干涉法是测量振动的有效方法,它具有精度高、空间分辨率高、与被测物体不接触等优点,故在振动测量上的应用日趋广泛.激光干涉法一般分为外差法及零差法两大类,外差法可测瞬态振动,且能辨别振动位相,但设备较复杂.零差法所需设备简单. 零差法的光电信号,对于大振 I. INTRODUCTION Laser interferometry is an effective method to measure vibration. It has the advantages of high precision, high spatial resolution and no contact with the measured object, so it is widely used in vibration measurement. Laser interferometry is generally divided into heterodyne Law and homodyne two categories, heterodyne method can be measured transient vibration, and can distinguish the vibration phase, but the device is more complex. Zero error method required equipment is simple. Zero-difference method of optical signals, for the vibration