Help me, Please . I have problem senior project about VGA

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I do z80 microcomputer. I am make Interface VGA Card connect to VGA monitor. I use 6845 CRT Controller generate dot and HSYNC , VSYNC (resolution 80 X 24). I new design color 3 bit color have Red, Green, Blue, White, Black, Cyan, Margenta, Yellow. Finally output have 5 Signal that R, G, B, VSYNC, HSYNC . But RGB is Digital TTL that is 0V and +5V. nowaday VGA Connector of PC Monitor is analog 0.7Vp-p and 75 Ohm. I don't know Circuit or IC use to Convert or drive RGB 0.7Vp-p 75 Ohm.
please tell me about information. Thank you for read.