| 摘要 |
PURPOSE:To print out a gradation density signal by providing a central processing unit for outputting a writing command to a writing control circuit by a command from a print key and reading the gradation density signal in an video memory and a printer. CONSTITUTION:An R.G.B. digital signal of TTL level is written in an video memory 1 in a timing of a clock P as a weight of G=2<2>, R=2<1>, B=2<0>A, writing control circuit 2 controls, by the use of horizontal and vertical synchronizing signals S1, S2 synchronous with the R.G.B., to write the R.G.B signal in a correct address of the video memory 1 as a gradation density signal of 640 picture elements in a horizontal direction and 234 lines in a vertical direction. When the writing to the video memory 1 is completed, a CPU 3 gives an address (a) to the video memory 1, reads a gradation density signal d2, and inputs to a printer 4 as a printing data d3. An R.G.G. primary color signal can be precisely printed out with a variable density of black and white.
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