Victor Sirius/9000 Monitor

Tony Duell ard at p850ug1.demon.co.uk
Sat Jul 7 15:41:21 CDT 2007


> 
> > A separate note in my diagrams says : 'VSync 75Hz,
> > HSync 16.1KHz'
> 
>  How is this possible? This would mean 214.67 lines of
> resolution (including overscan?). Am I goofy or

I wouldn't take those frequencies to be _exact_. It's quite possible it's 
214.5 lines or something.

> something? I had thought the V/S output 400 lines of
> resolution. Is it interlaced or sumthin? These

I think it has to be interlaced. That would then be about right for a 
400-line interlaced image. The video timing is contorlled by a 6845, 
which is quite capable of interlaced scanning, of course.

If it wasn;t interlaced, to get the same vertical resolution, either the 
vertical frequency would haev to be halved (which I don't believe for an 
instant -- did _any_ machine have a vertical sync frequency less than 
50Hz?) or the horizontal would haev to be doubled. From waht I remember 
of the hoprixontal output stage, I think that's unlikely too.

-tony




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