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Spectrum examination is widely used in scientific research and production. With the development of scientific research
and production, the trend of spectrum examination is from indoor to outdoor in situ examination and on-line monitor. So
the spectrometer is required to be more minimal. A new type of portable micro fiber spectrometer, using CCD, blaze
grating, and two spherical mirror, a small dispersing system based on crossing Czerny-Turner structure, is designed
based on this kind of requirement. By analyzing optical system structure, the relation among parameters of these
components has been found out in order to fix basic parameters for miniaturized spectrometer; its working wavelength is
200-910nm. The entire spectrum is detected by a CCD for one time, the selection of CCD is product of Toshiba
Corporation, linear charge coupled device (L.CCD) TCD1304AP, then received light signal is converted to an electrical
signal. The system's hardware circuit includes CPLD, MCU, the CCD driving timing circuit, signal conditioning circuits,
high-speed A/D sampling and transform timing circuit. A new kind of driving and sampling system which is high
integrated for multi-channel has been designed by using CPLD (complex programmable logical device) and MCU. In
this system, many function modules can be generated by logic cells inside of the CPLD chip, such as the driving pulse of
CCD, the driving timing of high-speed A/D sampling converter and storage system and so on. In the end, the A/D results
can be transmitted to computer by MCU for storage, processing and analysis. The CPLD is programmed in VHDL and
compiled, synthesized, simulated and burned with the helping of the environment of Quartus II. The design of portable
micro fiber spectrometer has the feature of wide spectrum range and high resolving power, so the system is especially
suitable in the application of portable filed examination.
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