波前功率谱密度(PSD)测量滤波器的设计

Design of Band-pass Filters for the Power Spectral Density Analysis

在采用波前功率谱密度评价大口径光学元件时,由于测得的原始数据受到测量系统引入的各种噪音和外界干扰的作用,会使检测准确度下降·对比引入带通滤波技术,对原始数据的有效滤波,减小带外的噪音分量和频谱混叠现象的影响·分别设计了无限脉冲响应带通滤波器和有限脉冲响应带通滤波器,通过模拟分析比较了两者的性能,得出在波前波前功率谱密度用于评价大口径光学元件的面形质量时,采用有限脉冲响应滤波器可以得到更高的测量准确度·

The detection accuracy will be reduced due to the disturbance of noise and outside to original data. it is necessary to apply the band pass filter in the wavefront power spectral density（PSD） analysis to handle this problem. The effective filter can reduce the effect of outside band noise and avoid frequency aliasing. The infinited impulse response band-pass filter（IIR） and the finited impulse response band-pass filter（FIR） were designed in this experiment. Characters of the two filters were compared by simulating analyse. And the result indicates that the better evaluation would be obtained if the FIR filter is used in the wavefront PSD which is used in testing large aperture components.