Based on the principle of grating pair modulation, a method of self-adaptive filtering in the light of incremental optical electrical encoder subdivision based on the models establishment of physical optics and geometrical optics is described. It also analyzed the reason why the photoelectric signals output for Moiré fringe are uncertain,remaining the original baseband signals by self-adaptive filtering high frequency signals. The result of self-adaptive filtering is equivalent to a narrowband band pass filter whose center frequency is original baseband and the pass band will change accordingly the original baseband with random variation. Experiments showed that application of this self-adaptive filtering technology can filter all the high frequency in the main count signal except original baseband so that the output waveform of Moirfe fringe photoelectric signals are close to the standard sine wave and the signal distortion is reduced by a factor of 8.%利用光栅副调制原理,在建立了光栅副调制几何光学模型与物理光学模型的基础上,提出了一种针对增量式编码器细分的自适应滤波方法.分析莫尔条纹光电信号输出波形不确定的原因,通过自适应滤波方法将高频信号滤除保留基频信号.自适应滤波效果等价于—个中心频率为基频的窄带带通滤波器,当基频随机变化时其通带也会随之改变.实验证明采用这种自适应滤波技术可以较好地滤除计数信号中除基频外所有高频分量,使莫尔条纹光电信号输出波形趋近于标准正弦波,将信号失真量减小了约7/8.
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