Research And Implementation Of Fast Recovery Method For Dual-Channel Fourier Transform Infrared Spectroscopy

This paper mainly focuses on the spectral recovery method of dual channel Fourier transform infrared spectrometer and its implementation.The key problems involved in the study are as follows:the influence of sampling error on the quality of the spectrum,the He-Ne laser interference signal zero-crossing reconstruction method,infrared interference signal reconstruction method and other issues were studied in depth to achieve the spectrometer spectral recovery system,and in the experiment carried out the practical application.Firstly,in order to study the influence of sampling error on the spectrogram,an error model is established,and the theoretical relation between sampling error and spectral ghost line is established mathematically.At the same time,the error model is simulated and the effect of linear interpolation method and cubic spline interpolation method on the zero-crossing of He-Ne laser interference signal is simulated.The correctness of the error model is verified by the above simulation,and the conclusion that the cubic spline interpolation with a He-Ne periodic sampling point can be the best to reduce the sampling error is obtained,the error range is reduced by 93%.Secondly,the effects of different methods on reconstructing the infrared interference signal on the spectral quality were compared.The experimental results show that two interpolation points of the linear interpolation method to reconstruct the infrared interference signal spectrum spectrum obtained by the highest signal to noise ratio increased by an average of 5.7%.On the basis of the above research,a dual channel Fourier transform infrared spectrometer spectral recovery system is implemented.The system uses a beam of He-Ne laser interference signals as a reference,while recovering two beams of polarized infrared interference signals,and then its apodization and fast Fourier transform to obtain two different polarization directions of the spectrum,and then the apodization and the fast Fourier transform are used to obtain two spectrums with different polarization directions.