Data Control System Concerning Fourier Transform Spectormeter Based On DSP

Fourier transform spectrometer with a high-pass optical capability, multi-channeldetection, high-resolution, wide spectral measurement, has become an important toolof the pro-gaze for spectral analysis. Spectrometer measurement needs to control thestage, also acquire and process the interference pattern on real-time, therefore itrequires high-performance data acquisition system. This paper designs a Fouriertransform spectrometer data control and real-time processing system. It uses thehigh-speed DSP as the central processor, in order to solve the restrictions on the use ofthe serial port and PCI, it uses the hot-swappable USB interface to implement datatransfer between device and the host.The main operation of this system is: the interferograms of two sources producedby interferometer are converted into electrical signals through photoelectric detectioncircuit. After folding the beam, the reference signal enters the zero-crossingcomparator circuit, at the hopping edge of the circuit triggers and generates thesample position pulse for measured signal. The DSP data acquisition system acquiresand processes the detection signal. After complementing of an acquisition, the data isread into the computer via the USB interface, and uses the virtual instrumenttechnology to display the signal interference pattern in the PC, also acquires thespectrum after Fourier transform, analyses the spectrum in terms of time domain andfrequency domain.This paper describes the entire system from two parts: hardware circuits andsoftware design. The hardware part includes a power supply circuit, a digital I/Oisolation circuit, A/D conversion circuit, CPLD logic timing control circuit, DSPperipheral circuit, USB interface circuit. The software part mainly designs the DSPsignal processing, USB firmware and PC software.Using the Labwindows (CVI)platform to realize the PC design, the main functions are connecting a USB device, DSP reset, DSP program download, controling the movement of the translation stage,data collection and display, saving the data, facilitating later with data analysis andprocessing.The system uses a USB2.0interface, making the system easy to use, fastertransfer speed, better able to adapt to the complex environment, it can complete thedata collection task very well.