Re: How to calculate the proper modeline? (DCF?
*-Jan Krupa <krupa@alpha.sggw.waw.pl>
|
| I am reading "XFree86 Video Timings HOWTO" and I would like to
| compute DCF/HSF but I do not know what DCF (dot clock frequency)
| is ? I mean I do not know where it comes from?
It's the number of pixels that the video card will send to the
monitor each second. Both the card and monitor must be able to
handle the DCF.
If you keep the resolution fixed and increase the dotclock the
monitor will refresh the image more often. If you keep the
refresh rate fixed and increase the dotclock, the resolution
will be greater.
| Synchronization :Horizontal: 30KHz-70KHz (Automatically)
| :Vertical: 50Hz-160Hz (Automatically)
|
| Video Bandwidth : 100MHz at-3db
This is the biggest dotclock that the monitor can handle without
much problem. It's not a fixed number, meaning that if you are
desperate, you can push it a little (but don't blame me if anything
goes wrong).
| So I think I can put HSF = 70000 and VSF = 160 but what about
| DCF ? Is DCF = 100 proper? How can I get it ?
|
| So shown below the Maximum allowed dot-clock: 250.000 MHz
| Is it connected to DCF ?
Yup, but you have to choose the minimum of the card and the monitor.
Conclusion: maximum DCF = 100.
--
Eschew obfuscation (go on; look them both up)
(Brian White)
olet@ifi.uio.no [-: .elOle. :-] olet@debian.org
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