| 摘要 |
<p>PURPOSE: To obtain efficiency by lowering the cost of a display memory which stores graphic data to be displayed on a video monitor and video data to be displayed in a window on a monitor in digital form and varying the processing speed of video information and graphic information. CONSTITUTION: The video data are transferred from the display memory 52 to a shift register 58 at a different speed from a pixel clock, and transferred at a pixel clock speed from there. The video data are stored in luminance form and chrominance form and converted by a color space conversion part 70 into three bytes representing the primary colors. The number of video pixels can be expanded by interpolation. The shift register 58 synchronizes with the increase and does not send data until the expansion of previous data is completed. Video window logic passes graphic pixels outside the window and video pixels in the window, passed from the shift register 58 through the color space converter 70 and an interpolator 72, at a graphic clock speed through a multiplexer 74. The data passed through the multiplexer 74 are latched at the graphic clock speed and converted into an analog signal, which is displayed as a color image on the video monitor 81.</p> |
