The Data Acquisition System For Multispectral Flat-field Portable Near-infrared Spectrometer

With the Near-infrared technology development in industry, agriculture, militar-y, scientific and research, spectral analysis technique has been a big development.Near-infrared spectroscopy is the most rapidly developing spectroscopic techniques.In the near infrared spectrometer, the performances of the photoelectric sensors havea great impact on the performance of the instrument. The development of sensors alsocontributed to the development of near infrared spectrometer, has played agreat role in the development of spectroscopy.Based on the issues that need, combined with practical application, hephotoelectric sensor was selected for TCD1208AP.This paper introduces the workingprinciple of the charge-coupled device, analysis TCD1208AP’s device characteris-tics and driven manner. The drive timing of the sensor was analyzed. This designuses the Altera Company EPM7128AETC100-10to driven timing. The chip microc-ells, I/O pins and other resources available, leave room for future functionality ex-pansion. In the design of the driver circuit before, the first to use theQuartus II software timing generator program has been designed. The design usesa top-down engineering design thinking, top-level files using a schematic way, theunderlying file using VHDL design, the design is complete after a waveform sim-ulation. In the hardware design of the drive circuit, the EPM7128-AETC100-10out-put signal is converted after74HC04level, the drive capacity increased pulsesignal output t o the TCD1208AP drive CCD charge storage, transfer and detection.In TCD1208AP signal output, the rail to rail op amp AD8042is used to designdifferential amplifier. Get the final output signal of the photoelectric conversionmodule of the linear CCD sensor.CPLD and VHDL to complete the drive timing ofthe CCD.Driver to simulate the design in the Quartus II.The correct transfer of the CCD signal to generate the control signals of the A/D and FIFO read signal,completion of adjustable integration time programming.VC++6.0is used to write the DLL of the CCD data acquisition.MATLAB andVC++6.0mixed, CCD-based acquisition system DLL and a diode array basedacquisition system DLL call connection, call DLL functions to achieve the goal ofdata acquisition and waveform display. Using MATLAB to designed the upperacquisition software, and processing the Acquisition data, achieve the goal of700~2500nm data collection.The spectral is range of the CCD at700~1200nm.Some models of the diodearray spectral is range up to1200~2500nm. Data is required in the near-infraredbands can be collected using the multispectral data acquisition system. In this paper, atwo-band flat-field spectrometer for the collection, use of two-band sensor datacollection, and data collected by two instruments, respectively, for wavelengthcalibration, data processing, to get the waveform of700~2500nm.After preliminary testing, the instrument has reached the design requirements, butthere are still several issues to be further studied, the following mainpoints: multi-speed integration time adjustable integration time adjustment; interfacetransfer rate; also need to the sample detection experiments; multi-band signalprocessing methods should be further improved.