| 摘要 |
PURPOSE:To enable graphic display by a memory of small capacity as well as the shortening of a processing time by exercising a random scan in a vertical blanking interval. CONSTITUTION:Once vertical synchronizing signal 102 is outputted from control circuit 12, selectors 16 and 18 are chaned over to the random scan side. During the execution of a raster scan, data 103 of an instruction from electronic computer 13 is stored in memory 14 and the data is outputted to graphic generating circuit 15 by control circuit 12 during the period of vertical synchronizing signal 102. Then, radom scan dta 107 and 108 of the instruction processed by graphic generting circuit 15 are outputted to selectors 16 and 18 and superposed upon a raster scan pattern to display a random scan pattern. During the period of vertical synchronizing signal 102, the dandom scan is carried into effect and at the other time, the raster scan is carried out. |
