论文部分内容阅读
在利用干涉仪和光栅进行长度测量的仪器中,干涉条纹的对比度、频率和信噪比等因素,将直接影响到光电转换后信号的对比度、幅度和信噪比。其中,以干涉条纹的对比度和干涉条纹数(在接收视场中)对转换后信号的对比度影响最大,若不注意两者的配合,则会带来光电转换的非线性失真。干涉条纹的对比度K为:K=(I_(max)-I_(min)/I_(max)+I_(min)) (1)
In the interferometer and grating length measurement instruments, interference fringes contrast, frequency and signal to noise ratio and other factors, will directly affect the photoelectric conversion signal contrast, amplitude and signal to noise ratio. Among them, the interference fringes contrast and the number of interference fringes (in the receiving field of view) have the greatest influence on the contrast of the converted signal, and if the two are not matched, the nonlinear distortion of the photoelectric conversion will be brought. The contrast K of the interference fringes is: K = (I max - I min / I max + I min min) (1)