Research For Acquisition And Spectrum Recovery Algorithm Of Photoelastic Modulator Nonuniform Interference Data Based On DSP

Fourier Transform Infrared Spectrometer(FTIR) is widely used in the Infrared remotesensing, nuclear magnetic resonance (NMR), space exploration, and many other fields due toits unique fast scanning speed, high sensitivity, wide spectrum range, good shock resistanceand a lot of advantages. The photoelastic modulator interferometer is the key part of the FTIRspectrum analyzer. It is a new type of static scan system, and it overcomes the early manydrawbacks of Fourier transform spectrometer.The paper bases on the analysis of the difference between FTIR and ordinaryspectrometer, and then with the requirements of the project, the relevant situation andtechnology all over the world, it studies interference data difficult to be achieved by phasesampling in the photoelastic modulator because of the characteristic of the refractive indexwith sinusoidal modulation, and then studies the non-phase (or time interval sampling)spectral inversion algorithm, namely nonuniform fast Fourier transform algorithm(NUFFT).Finally the spectrum data is real-time processed and spectrum information is recovered usingadvanced DSP+FPGA technology with NUFFT algorithm on the hardware DSP.Finally, the tests are carried on the basis of the theory verification and laboratoryconditions, different wavelength lasers(632.8nm、652.6nm、671.1nm) is used in order to getspectrum, and then the spectrum information is recovered. The experiment results show thatnonuniform fast Fourier transform algorithm can completely recover the spectruminformation for the interference data of monochromatic light and polychromatic light, therecovery accuracy and recovery rate meet the requirements of the project.