傅利叶变换光谱技术中的"折叠假线"研究

根据奈奎斯特(Nyquist)采样定理,解释了傅利叶变换光谱采集过程中由于折叠而出现的假线现象,并且对假线的特点进行了预测,进而总结出实验过程中利用光学滤波器和电子学滤波器来防止假线,同时兼顾信噪比的实验参数设置方法.经实验证实,这套方法是行之有效的.

False Lines due to Folding in Fourier Transform Spectroscopy

The phenomenon of false lines due to folding in Fourier Transform Spectroscopy is explained using by Nyquist sampling theorem The characters of false lines are discussed. The key to avoid false lines is to use suitable filters to remove the signal outside the wanted spectral region. Two kinds of filters, optical and electrpnic filters namely, are compared to serve this purpose. It is found out that both kind of filters should be combined in order to prevent folding as well as secure a good signal to noise ratio. Some experimental parameters setting rules are advanced. The method proved to be successful in our experiments of recording the v= 3 and v=4 highly vibrational spectra of arsine.