FPGA-based Fourier transform infrared spectrometer moving mirror scanning control module

Abstract

The invention relates to an FPGA-based Fourier transform infrared spectrometer moving mirror scanning control module, which comprises a laser detector and a signal shaping circuit, a frequency-voltageconversion circuit, a subtractor, an analog PID circuit, an electronic switch II, a control line II, the FPGA, a D / A conversion circuit, a starting force circuit, an electronic switch I, a directioncontrollable circuit, a control line I, a control line III, an optocoupler circuit, a power amplifier circuit and a voice coil motor. Through adjustment on a potentiometer in the frequency-voltage conversion circuit, the scanning speed of the moving mirror can be slightly adjusted, and thus, the speed requirements of technical indicators can be met. The FPGA itself has multiple other functions inthe circuit design, plus control on the moving mirror, the FPGA is made full use of, the burden of a main control CPU is reduced, the waste of resources and the competition among the functions of theCPU are solved, and the system can run more reliably and efficiently. Due to dual application of the frequency-voltage conversion circuit and the analog PID circuit, scanning of the moving mirror is more stable, reliable and uniform.

Description

technical field [0001] The invention belongs to the technical field of spectrum analysis instruments, and relates to a moving mirror scanning control module inside a Fourier transform infrared spectrometer. Background technique [0002] The core of the Fourier transform infrared spectrometer is the interferometer. At present, the interferometer mostly adopts the traditional Michelson interferometer or its deformation. The interior of the interferometer mainly includes a beam splitter, a moving mirror and a fixed mirror. The laser beam and the infrared beam are respectively formed inside the interferometer. Interference, the movement of the moving mirror causes the change of the optical path difference of the coherent beam, which in turn causes the change of the interference signal detected by the detector. The uniformity, stability and fine-tuning of the moving mirror speed directly affect the interferometer. technical performance indicators. [0003] At present, most of th...

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Problems solved by technology

[0003] At present, most of the new Michelson interferometers use a CPU chip plus a grating encoder plus an analog PID controller, or a digital PID controller with a CPU as a control chip as a driving module for moving mirror scanning to drive a voice coil DC motor. It is a waste of resources to use the CPU chip to control the module. If the CPU is also used for other control and data processing, it will cause competition between functions and cause instrument instability.

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