Yes, there are more differences between NTSC and PAL than simply the frequencies. The most obvious ones are that the color subcarrier is at a different frequency (3.58MHz/NTSC, 4.43MHz/PAL)... that's why you'll get B&W picture if you connect a PAL TV to an NTSC S-vid. The horizontal scan frequencies are 15.734kHz vs 15.625kHz... most likely close enough to lock onto for the luma with sync. The 50/60Hz is another matter, but from what I understand lots of PAL TV's are at least pseudo-capable of viewing NTSC video, so the vertical scanning might be able to lock onto a 60Hz refresh even if it was designed for 50/100.The AD724 supports PAL encoding as well as NTSC, so it should be
But there is something different that goes beyond the frequency, AFAIK. If I connect a PAL TV to an NTSC S-vid, I would get a B/W picture. Or was that with composite (cinch)? Or is that AD724 switchable between PAL nad NTSC?
Now, for the chroma on the s-vid, everything is *way* off. 3.58 is much different from 4.43 no matter how you slice it. So, it'll not get much color info from it.
To answer your question easier, though... YES the AD724 has a PAL mode. Feed it a correct PAL color subcarrier frequency, change one pin, feed it PAL RGBHV frequencies, and it goes. I haven't done it, mind you, but it should work fine.
Correct. I haven't noticed artifacts with what I'm doing, but I suspect that the chip does some filtering. I haven't looked at the datasheet in awhile.That's right. But not all TVs have RGB-capable scart connectors.
On the other hand, if you would do VGA->SCART with RGB, you would have basically this, right?
http://www.sput.nl/hardware/tv-x.html
Someone else here wrote, that RGB is *too* sharp for MPEG2 video, meaning that you see the artifacts then.
-Cory
************************************************************************* * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * *************************************************************************
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