Random Scanning To The Development Of The Raster Scan Conversion Equipment

This paper discuss the key techniques used in Stroke to Raster Scan Conversion(SRC): The fundamentals of video scan conversion. A practical scan conversion system based on CPLD is proposed, in which CPLD is used to control SRC system flexibly and it realizes stroke to taster scan display system conversion. The SRC-1 Stroke-to-Raster Converter is a general purpose stroke-to-raster converter which converts video in X,Y,Z (stroke) format to SVGA (800*600) raster video in real time. The unit is capable of processing stroke symbology image data to generate an image which can be recorded or displayed on standard video equipment.The unit receives X deflection,Y deflection,Z video intensity (bright-up) from the host system. X deflection and Y deflection are analog differential signal. Z bright-up signal is dignal differential signal. The Z bright-up signal is used as the source of video to be written to the SRC.The input video from the selected source is received by transceivers for RS-485/RS-422. The amplitude of the X deflection and Y deflection signals determine where the sampled input data is placed in the SRC frame buffer. The deflection signals are sampled to 9-bit accuracy to ensure that resolution is preserved.A combination of proprietary analog and digital signal processing/filtering techniques are used to eliminate noise on the input signals, and to prevent aliasing or other potential image artifacts.Multiple frame buffers are used to permit the input and output frame rates to be completely independent. Information from the currently-designed output buffer is passed to a D/A converter and converted to analog format.I complete design and stimulation of the circuits under the environment of MAX+PLUS II and realize the relevant logic circuit design by using the programmable logic device CPLD (Complex Programmable Logic Device) of ALTERTA. The SRC-1 module can be used wherever it is necessary to convert video in X,Y,Z (stroke) format to standard highresolution video format. The results are useful to the video conversion field.