Static Fourier Transform Spectroscopy Detection And Real-time Processing System Based On FPGA

With the rapid development of spectroscopic techniques, the Fourier transform spectroscopy has been applied more extensively. Through the survey of current state of research both at home and abroad, the author finds out that the Fourier transform spectrometer has high spectrum resolution, high luminous flux, and especially has the unique advantage of weak signal monitoring. However, the deficiencies of slow mechanical scanning and unstable system exist. The static Fourier transform spectroscopy detection and real-time processing system which are all based on FPGA are designed in this dissertation. This design can help to obtain the real-time spectroscopic information such as battlefield laser, atmospheric pollutants gases, poison gas, etc. and to overcome the mechanical scanning and poor real-time software processing in spectrum recovery.According to the Fourier transform spectroscopy theory, the design scheme of the Fourier transform spectroscopy detection and real-time processing system is eastablished in this dissertation. And the principles of the system, the features of the equivalent static interference wedge, and the mathematical treatment of interference fringes, especially the radix-2 Fast Fourier transform algorithm are described in detail. Based on the mastery of Verilog Hardware Designing Language and Field Programmable Gate Array constructure of Xilinx's chip, the ISE10.1 development platform is used to design the system modules, which contain the CMOS optical detector driver circuit, series to parallel conversion circuit, asynchronous read and write RAM, radix-2FFT algorithm module, phase correction, data transmission module and so on. And the functional simulation of each module is completed through the third-party simulation software: Modelsim6.3f. After being successfully debugged, the system program is downloaded into the FPGA chip to process the interferece fringe. And the actual calculated values are concordant with the MATLAB theoretical values. The results show that the design of the data processing system is correct.Finally, the equivalent static interference wedge optical system is set up in the laboratory, and the circuit system consisting of Virtex2-ProFPGA development board and expansion board of CMOS detector is combined with this system to make the laser spectroscopy detecting experiment. At last, the acquisition interference fringe image and the spectrum recovery processing results are displayed by the upper computer.