hi, I am designing a VGA to NTSC/PAL converter card for my home computer. For the conversion part i used the VGA chip AD724.I wire the circuit in the datasheet itself. i used the srystal for NTSC output. But i didn't get any picture on TV screen. There was only a white screen with one small black line on the middle of the screen. Anybody have experiance with this AD724 chip. Pls help me to get the correct output on TV screen.
You realize that the AD724 is simply an encoder, right? It makes a composite signal from RGB but the line/frame rates must be NTSC. Wouldn't it be easier to simply buy an ATI (or others) video card with composite out? I bought one last year at Fry's for $50. GG
Seems pretty unlikely that you can do a project like this without an oscolloscope to view your waveforms.
For starters, TV frame rates are rarely compatible with their computer counterparts. That's big problem #1 !
That's a guess as to your problem since you don't provide enough information to deduce any more.
Graham
snipped-for-privacy@gmail.com expuso:
You must set your PC card to output the correct frame rate. Look for drivers that will do this or try the PowerStrip program, that depending on your card model will let you set up any frame rate. You'll have to play with all the timing settings or look at groups.google.com for NTSC values that other people has worked out.
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