Design Of Data Acquisition System For Handheld Raman Spectrometer

For its unique molecular spectral characteristics,Raman spectroscopy is often used in many fields,such as medical treatment,environmental protection,security,quality inspection.With the development of laser technology and manufacturing technology,Raman spectroscopy technology is becoming more and more mature,and the spectrometers based on the technology are becoming more and more diversified.In order to meet the requirements of outdoor real-time detection,high temperature,high pressure and other special environments,the handheld Raman spectrometer came into being.However,the existing hand-held Raman spectrometer has many shortcomings such as weak effective signal,narrow application range and expensive product price,which affects the practical experience.Therefore,this paper aims to develop a low-cost and excellent performance high-throughput hand-held Raman spectrometer,and mainly studies and designs its data acquisition system.In this paper,the development status of hand-held Raman spectrometer at home and abroad is introduced in detail,and the principle of Raman scattering and the working principle of CCD are studied.On this basis,the structure of the optical path involved is improved to be suitable for the hand-held Raman spectrometer developed in this paper.Then the circuit of the data acquisition system is designed reasonably,including laser module,micro spectrometer module,power module.According to the actual design requirements,FPGA is chosen as the control chip of the underlying hardware,and UART communication protocol is used as the data transmission protocol,which ensures the stable conversion,cache and transmission of data.Finally,in order to overcome the signal interference caused by the system hardware and external environment,a variety of algorithms are designed to optimize the signal,such as filtering,smoothing and baseline correction.At the same time,the data matching algorithm is added to make the matching results of the samples to be tested more credible.After debugging and experiments of each functional module and algorithm,the output power of the laser is stable and adjustable,and the algorithm is effective and feasible.The resolution of the prototype is 1.5nm,and the SNR is 312:1.The qualitative test results of anhydrous ethanol,ethyl acetate,methanol,cinnabar and phenobarbital can be obtained within 6s with a matching degree of 90% with the standard library,which shows that the prototype can meet the measurement needs of a few samples at present,and can be optimized continuously in the future.