Design Of Control System For Multi-Channel Optical Fiber Spectrometer Based On FPGA

Spectrometer is a physical optical equipment that uses optical principles such as dispersion,absorption and scattering of light to obtain the spectrum related to the analyzed substance,so as to analyze the structure and composition of the substance.It has been widely used in many fields.Because of the restriction between wavelength measurement range and wavelength resolution of single-channel optical fiber spectrometer,and with the increasing requirements of the performance of spectrometers in the scientific field,multi-channel spectrometer has become a research hotspot in various countries.The control system of the spectrometer is the core part of the multi-channel optical spectrometer.In this paper,designs and manufacture a control system for the acquisition,processing and transmission of multichannel spectral data,and briefly introduces the optical system of the multi-channel spectrometer,and combined with the upper computer software to test the multi-channel control system.In the process of system design,the overall scheme of the system is designed firstly.In the hardware part,the system is divided into several modules,including FPGA control module,CCD photoelectric conversion module,A/D conversion module,USB communication module,RS232 communication module,power module and storage module.The hardware circuit diagram and chip selection of each module is designed respectively.According to the system design requirements,the CCD device selects linear array TCD1304 DG device,each channel corresponds to a CCD device.A/D conversion chip selects AD9826 of special image processor.USB2.0 interface as the serial port of spectral data transmission and control system communication with upper computer.In order to improve the processing speed of spectrometer and realize synchronous acquisition of multiple channels,FPGA is selected as the control chip.In the software part,based on Verilog HDL hardware description language,the general functional state diagram of the system is introduced firstly.That is,the spectrometer control system realizes the collection,processing,storage and transmission of spectral data under the control of the upper computer commands.The design of CCD and AD acquisition and control timing sequence,the storage and reading of spectral data and the logic of USB communication are mainly introduced.After the design of the hardware and software of the control system is completed,a prototype of the spectrometer is built with the optical system,and the prototype is tested with the software of the upper computer.The system meets the expected design requirements and can realize the synchronous acquisition of spectral data between multiple channels.It has important practical significance in the research of multi-channel optical fiber spectrometer.Finally,the main work of designing multi-channel optical fiber spectrometer in this paper is summarized,and the next research direction is proposed for some existing problems.