Research On Gain Control System Of Photoelectric Detection Based On FPGA

With the development of science technology and production,photoelectric detection technology with its advantages of high sensitivity,ultra-fast response speed,extremely low noise and relatively low development cost,makes the detection and processing of photoelectric information become a very important research content.The development of photoelectric technology is increasingly valued at home and abroad,and has formed a modern high-tech optoelectronic industry.In the actual detection process,we often encounter optical signals with different intensities,and their signal intensities may vary greatly with time,which puts forward that our detection system should have high sensitivity,fast response speed,and high precision gain change ability,so that the signal acquisition can be better presented.This paper fully investigates the current existing principles and applications of photoelectric detection.Aiming at the practical problems and needs of plasma signal detection of magnetically constrained tokamak device,combined with the research on the gain adjustment method of the photoelectric detection system,the way of adjusting the gain of the photomultiplier module is selected,and a photoelectric detection gain control system based on FPGA is designed.The system is controlled by upper computer software and realized by lower computer hardware.The lower computer hardware program is written in Verilog HDL to output the control voltage of the upper computer to realize the remote control of the gain of the photoelectric detection system.Firstly,the single-board system design of the gain control system is introduced in detail.The single-board hardware implementation includes main device selection and system circuit design.The single-board software design introduces the design of each sub-module in detail from two parts: FPGA program and user software design.In the laboratory and the 2019 EAST autumn plasma discharge experiment D ? radiation diagnosis,the functional test and field performance test of the single board system were carried out respectively.The experimental results show that the system can adjust the gain of the multi-channel photoelectric detection system stably and accurately,which can provide help for the detection of plasma signals with different amplitude and large magnitude differences.Based on the single board system,the multi-channel and multi board system is developed.The design of the multi board system mainly introduces the communicationprinciple and the program realization in detail,and uses the chip integrated signaltap II software to verify the program operation.