弹光调制傅里叶变换光谱相位校正及DSP实现  

Photo-Elastic Modulation Fourier Transform Spectrum Phase Correction and DSP Implementation

作　　者：李珊[1] 陈媛媛[1] 王志斌[1] 张敏娟[1] 景宁[1] 

机构地区：[1]中北大学,山西省光电信息与仪器工程技术研究中心,山西太原030051

出　　处：《光谱学与光谱分析》2017年第2期374-378,共5页Spectroscopy and Spectral Analysis

基　　金：国家国际科技合作专项项目(2013DFR10150);国家自然科学基金仪器专项(61127015);国家自然科学基金青年科学基金项目(61505180,61605176);山西省青年科技研究基金项目(2015021084,2014021012,2013021028-1)资助

摘　　要：弹光调制傅里叶变换光谱仪(PEM-FTS)具有调制速度快、信息量大的特点,但采样位置偏差会导致干涉图存在相位误差,影响复原光谱的准确性。因此,必需采用一种运算速度高的相位校正方案。以300K黑体为辐射源,通过弹光调制干涉具产生干涉数据,并在TMS320C6713DSP芯片上,采用Mertz法对弹光调制干涉图进行相位校正。首先提取出一幅完整周期的双边干涉图,经过切趾处理后,以零光程差点为中心计算小双边干涉图的相位误差,再通过插值补零得到整幅干涉图的相位误差,求出整体干涉图的频谱并进行相位修正。采用二范数定义校正后反演光谱的精度,以计算定时器周期寄存器值的方法设置DSP定时器,以统计代码的运行时间,并通过观察链接命令文件.cmd中程序与数据的分配存储情况,来对比分析Mertz法与模平方法的校正结果。实验结果表明,在DSP上实现相位校正时,Mertz法相位校正方案具有运算速度快、占用存储空间少、误差较小等特点,并且Mertz相位校正法的运算时间较模平方法快20倍,适用于对PEM-FTS干涉图进行高速准确的相位校正。Photo-elastic modulation Fourier transform spectrum（PEM-FTS）has the characteristics of fast modulation speed and large amount of information.However,because of the sampling position error and other reasons,there exists phase difference in the output interference data,which affects the accuracy of the reconstructed spectrum.Therefore,aphase correction scheme with high computing speed must be adopted.The 300 Kinfrared blackbody was used as the radiant source in the experiment,and interference data were generated by the photo-elastic modulation interferometer.Mertz method is used to correct the phase of photo-elastic modulation interference data on the TMS320C6713DSP（digital signal processor）chip.First a complete double interference data is extracted befroe the apodization processing to calculate the phase error of small double interference data,which takes the zero optical path as the center.Then a whole interference figure error phase is acquired with interpolating zero and the spectrum of the complete interference data and correcting phase are obtained at last.With two-norm to define the accuracy of corrected spectrum,and using the method of calculating timer period register to count code running time,and observing program and data memory space in the file of command.The correction results of Mertz method and modulus square method were analysed comparatively.Experimental results show that Mertz method has advantages of fast speed,occupying less storage space and less correction error when implement phase correction on the DSP.And the operation time of Mertz phase correction method is20 times faster than that of modulus square method.Consequently,it is suitable for high speed and accurate phase correction of PEM-FTS interference data.

关 键 词：弹光调制 相位校正 DSP Mertz法 模平方法 

分 类 号：TN911.74[电子电信—通信与信息系统]