一种整小数结合式激光外差信号处理方法

为解决在纳米级分辨力激光外差干涉测量中,由于倍频计数限制引起的在大量程条件下测量分辨力难以提高的难题,提出一种新颖的基于锁相环倍频和相位解调技术相结合的整数、小数结合计数式检测方法。该方法采用数字电路式对顶、错位脉冲消除预处理法得到外差信号的整数相位,再采用高分辨力的鉴相方法获得小数相位,并实现整数、小数相位的正确结合。实验和分析结果表明:采用该方法的激光外差干涉测量系统,动态测量分辨力达到10 nm,与HP5528在1.2m的测量范围内比对测量结果的差值小于0.09μm,静态测量相位分辨力为0.011°,对应的静态测量分辨力优于0.1 nm。应用提出的测量方法,为大范围高分辨力的动态位移测量提供一种有效的技术途径,同时,提高了激光外差干涉系统的测量分辨力。

Laser heterodyne interferometry signal processing method based on integer-fraction combined phase counting

In order to achieve high measuring resolution in wide measuring range with laser heterodyne interferometry measurement in nanometer level,a novel integer-fraction combined signals processing method is presented.Both traditional phase measuring method for inner-period measurement and frequency multiply counting method based on phase locked loop for integer periods measurement are used.The integer phase is obtained by eliminating opposite pulses and alternate pulses,and the fraction phase is obtained using phase demodulation method of high resolution,then combine them correctly.The experimental comparison and analyses indicate that resolution of distance-measurement 10 nm,the difference less than 0.09 μm in the range of 1.2 m comparing with HP5528,the static phase resolution of 0.011°and the static resolution better than 0.1 nm can be achieved in laser heterodyne interferometry measuring system using the proposed method,and this method is also an effective way in displacement measurement with wide measuring range and high measuring resolution.