傅里叶变换红外光谱仪量化误差仿真分析

Computer simulation analysis of quantization error of Fourier spectrometer

分析了数模转换器的量化误差对傅里叶变换红外光谱精度的影响。采用积分转离散求和的方法对干涉图进行建模仿真分析。将干涉图信号经过8位、12位、16位以及20位数模转换器转换之后进行快速傅里叶变换,最后解谱光谱数据。同时,也定量比较了不同位数的数模转换器的光谱图相较于原始光谱图的偏离程度,以及在吸收峰位置分析量化误差对光谱图偏移的影响。结果表明,20位数模转换器的平均偏离误差为1.884 97,且该模型可作为由量化误差引起相关误差的修正算法的理论依据。

The influence of quantization error on infrared spectral accuracy of Fourier transform is analyzed.The method of integral to discrete summation is used to model and simulate the interferogram.The interferogram signal is subjected to fast Fourier transform after converted by digital-to-analog converters with 8 bit,12 bit,16 bit,and 20 bit,and the spectrum data is decoded.At the same time,the deviation degree between the spectrum diagram of the digital-to-analog converter with different bits and the original spectrum is quantitatively compared,and the influence of quantitative error for the spectrum migration is analyzed at the position of the absorption peak.The result shows that the average deviation error of the 20 bit digital-to-analog converter is 1.884 97,and the model can be used as the theoretical basis on the correction algorithm of correlation error caused by quantization error.