| 摘要 |
A coloured display for a computer is derived using a first set of digital words representing locations in a pixel matrix for the pattern to be displayed and a second set of digital words representing foreground and background colours for the pattern on the basis of a conventional character display whereby to reduce the amount of storage required for the colour information while permitting high resolution graphics. Circuits are provided for converting digital R, G, B signals into analogue Y, U, V signals and each of these circuits comprises a control transistor in whose collector circuit is connected the base of an output transistor and in whose emitter circuit are connected parallel switches and resistances which switches are controlled by signals derived from the digital R, G, B signals whereby to alter the base bias of the output transistor. |
