| This paper uses Lab VIEW development tool to construct a composite video signal generating and processing system based on the NI PXI system platform.The system can generate the corresponding video file from the frame by frame picture and transform the video file to analog video signal via the arbitrary waveform generator card on the PXI system. Then the analog signal can be output to the color TV to display.Analysis and implemention of the system in this paper are started from a profound understanding of the various parts of the composite video signal (baseband video signal) first, analyzing the role and significance of the information contained in the composite video signal in detail, including image information and other synchronous auxiliary information. Then, on the basis of understanding the signal composition, standard format video file is generated used my own algorithm and the relevant problems are explored deeply. The solutions of these problems in the system are proposed, for example, how to build the color burst signal and the image signal of each line. After that, this paper reserches how to apply the relevant hardware of NI PXI system to output the analog signal generated by video file to the color TV, and introduces two operating modes of the arbitrary wave generator card, trigger mode and stream mode, describing their workflows detaily. At last, this paper explores the performance achieved in the system briefly, for example, the best play rate in the two mode and how the adjustment of the corresponding attribute affects the video playing performance in each mode.At the end of this paper, futher work of the system is put forward and the sytem is expected to be improved to a general signal generating and processing system with more precise algorithms and a better performance. |
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