The Design Of Miniature Spectrometer Based On Linear CCD

Since Newton has divided sunlight into seven-color ray. The spectroscopic technology has developed greatly. Spectrometer is optical instrument used in spectroscopic analysis to identify materials, which is applied in almost all fields of science, such as medicine, chemistry, geology, physics and astronomy, etc.In recent years, with the development of the modem techniques, miniature spectrometer has become a research focus worldwide. Compared to traditional large scale spectrometer, miniature spectrometer has many advantages such as compactness, light-weighting, convenience and low price; at the same time, it is more convenient to use it as photoelectric interface to joint fiber optic probe. Thus, it is the trend of the spectrometer.First, this paper proceeds depth theoretical analysis on the construction, principle and basic characters of the dispersive spectrometer. On the basis of theoretical analysis and comparison, we choose the symmetrical Czerny-Turner optical path system. Then, the application technique of CCD has been studied. An miniature spectrometer based on high speed linear CCD sensor has been designed. According to the requirement of spectral measuring application, we choose 3648 pixels TCD1305P as detector to collect the spectral signal. CCD output signal converted to digital signal by AD9200 after amplified in adjusting circuits. We achieved the real-time transport of the spectral data based on USB interface chip CH372, and the USB provide miniature spectrometer with power supply so the system requires only a USB cable, and can use it immediately after the connection cable is connected to the computer.FPGA is the core of this system, which drive the CCD,AD9200 and control USB data transport as well as the whole system. We designed the hardware circuits and PCB with Protel DXP, and then completed the realization of each logic module which programmed in Verilog Hardware Description Language. The design is optimized on simulation testing to achieve the best reliability using EDA tools such as Modelsim, Quartusâ…¡and Synplify. On the other hand, this design takes full account of the electromagnetic compatibility of the CCD device, minimizing the noise interference by the system to ensure stability and reliability of the CCD.