Research On High-speed Sampling System Of Fourier Transform Infrared Spectrometer

Fourier transform near-infrared spectroscopy is one of the most important techniques in today's analytical test.Among optical analysis methods,near-infrared spectroscopy is a very important analysis method based on the molecular absorption of infrared radiation and the main advantage is that each compound has infrared absorption,which can be measured in very wide range.Currently,this method is mainly applied in material structure analysis,reaction mechanism research,material qualitative and quantitative analysis and in other fields.Due to the use of near-infrared spectroscopy which is very stable,reliable and effective,the technology is frequently used in drugs analysis and other special areas.In order to ensure the safety and effectiveness of the analysis,non-difference sampling of infrared spectral information has long been paid great attention by scholars.This thesis mainly introduces the design of spectral information acquisition system based on Michelson interferometer.In this paper,the development of FTIR spectrometer and acquisition circuit is briefly introduced.The main part introduces the principle of FTIR spectrometer,the hardware design and software design part of high speed sampling system.Hardware design contains conditioning circuit design and acquisition circuit design.The conditioning section includes the design of the segment gain of the interference signal,the signal amplification and the filter design.The design of acquisition part mainly uses ?-?ADC to determine the system has 12-bit sampling accuracy and 65 Msps conversion speed.The Xilinx-s6 series of FPGAs(Field Programmable Logic Gate Arrays)are used to sample the master core and its peripheral memory and Communication configuration.The acquisition part successfully reaches the goal of high speed real-time acquisition and storage of the interference light data,possessing the capacity of stable data processing.The software part is mainly based on the multi-channel design used in the hardware design and the Michelson interference signal of the near-infrared light is collected by the three-channel acquisition and the spectral data obtained after AD conversion.Under the MVDR criterion,the statistical optimal weight vector is obtained by linear constraint(LCMV).The optimal weight vector is analyzed and compared with the signal-to-noise ratio before and after the linear constraint.In the conclusion part,this paper analyzes a group of measured spectral data collected in different cases and the results show that the scheme of multi-channel high-speed interference data acquisition system is designed to meet the requirements of real-time andhigh-precision.