Design Of Data Acquisition System For Micro Spectrometer

Spectral dimension information is one of the intrinsic properties of substances,and spectral detection technology can precisely detect the intrinsic properties,so it has been widely used in scientific research and development,material analysis,health care,anti-terrorist security,water quality monitoring and other fields.Spectrometer is an effective tool for spectral measurement.However,the traditional spectrometer has a series of disadvantages,which cannot meet the needs of online real-time measurement and other special application scenarios.Therefore,the micro-spectrometer has become one of the hot spots in the current scientific research.At present,the domestic and foreign micro-spectrometer and its related industries are in the stage of rapid development,the market prospects are huge.In this paper,the spectral sampling requirements are analyzed in advance,and then researched and selected the appropriate optical device and electronic device.Finally,a spectral data acquisition system with excellent performance is designed.The acquisition system mainly includes optical structure module,hardware driver circuit module and upper computer analysis software module.This paper focuses on the hardware circuit module and upper computer software module.The hardware circuit module includes three parts: sensor driver,signal processing and cache,and signal transmission and communication.In this module,the appropriate FPGA chip and CCD sensor are selected according to the actual measurement requirements,and the design,simulation and development of each chip and its peripheral drive circuit are completed.The three communication ports of USB,UART and SPI are developed to improve the diversity of data transmission,expand the application scope of this spectrum acquisition system,and lay a solid practical foundation for the research and development of handheld Raman spectrometer and other related devices.In the upper computer software module,it not only realizes the real-time display and storage of spectral data,but also adds the spectral data preprocessing functions such as average smooth noise reduction,nonlinear correction and wavelength calibration,which to some extent makes up for the inherent defects of the underlying hardware.Through a large number of experimental measurements and verifications,the technical parameters of the micro-spectral acquisition system are comprehensively evaluated.The experimental results show that the maximum signal transmission speed of USB port can reach 36MB/S,and the data packet loss rate and bit error rate are very low.In the aspect of algorithm optimization,the nonlinear correction effect is remarkable,and the nonlinear degree of the system is less than 0.5% after correction.The wavelength calibration function is normal,and the error after calibration is only 0.33 nm.The SNR of the whole machine is better than 300:1,the spectral resolution at the edge wavelength is 1.54 nm,and the spectral resolution near the center wavelength is as high as 1.27 nm,which fully meets the requirements of different application fields.