激光合成波长干涉仪零相位检测实验研究

Experimental Study on Zero Phase Detection of Laser Synthetic Wavelength Interferometer

探讨激光合成波长干涉仪零相位检测方法,构建基于DSP芯片TMS320F28335的零相位检测实验装置,选用两个捕捉单元获取两单波长干涉信号的上升沿时刻差,用线性回归拟合方法算出零相位点位置。在恒温恒湿实验室中,分别以7 000、10 000和13 000个拟合点数进行实验,实验结果显示,参考镜过零点位置平均值分别为283 388.8、285 830.9、286 533.2μm,标准偏差分别为0.25、0.43、0.36μm。结果表明:选取7 000个拟合点数进行计算时,标准偏差最小,计算得到的过零点位置最准确。

This paper discusses zero phase detection method of laser synthetic wavelength interferometer; establishes zero phase detection experimental apparatus based on DSP chip TMS320F28335; uses two capture units to obtain the rising edge time difference of two single wavelength interference signals and calculates the position of zero phase point with linear regression fitting method; conducts experiments respectively with 7 000, 10 000 and 13 000 fitting points in the laboratory with constant temperature and humidity. The experimental result shows that mean values of zero crossing point of reference mirror are respectively 283 388. 8, 285 830. 9 and 286 533. 2 μm and standard deviations are respectively 0. 25, 0. 43 and 0. 36μm. The result shows that the standard deviation is the smallest and the zero crossing point obtained through calculation is the most accurate when 7 000 fitting points are used for calculation.