Research On The Spectrum System Using Linear Array CCD Based On CPLD

Spectrometer is an important analytical instrument for the physical and chemical composition of substances. Traditional spectrometer has several shortcomings such as large volume, expensive price and slow scan speed, so it is used only in the laboratory, whose engineering value is very limited. The high-performance and inexpensive spectrum measurement system has huge needs in the field of automatic measurement, equipment test, security monitoring and control. Therefore, miniaturization, cost reduction and real-time dynamic measurement of spectral measurement system has become the main direction of research.This dissertation firstly studied the shortcomings of the existing spectrometer. On this basis, it designed a spectral information collection system using linear CCD based on CPLD. The software and hardware design used the modular concept. The whole system could be divided into the optical detection module, signal acquisition module, data transmission module and driver control module etc. The optical detection module used a linear CCD sensor, changing optical signal into analog current signal. The signal acquisition module used AD9945 chip as analog-digital converter chip, which was specifically designed for single-channel CCD signal processing. AD9945 have functions such as correlated double sampling, direct reconstruction and 12 high-precision sampling to complete analog current signal acquisition with high-speed. The data transmission module used USB chip CY7C68013 as the data transmission device to realize crew spectral data real-time transmission with high-speed. The driver control module uses CPLD as a core element, which completed the function such as optical signal acquisition, conversion, timing driven, transmission and storage. The system took full account of the high-speed data transmission and noise suppression.At last, this dissertation made a modular debugging for each part of the spectrum information acquisition system. The detailed analysis of our debugging results for each module was made. In addition, this paper conducted a comprehensive experiment of the whole system. The experiment tested the spectral data detected by the system while CCD in non block and in partial block. The experiment showed that the system can accurately capture real-time spectral data.