Re: [stella] end of frame??

Subject: Re: [stella] end of frame??
From: Chris Wilkson <ecwilkso@xxxxxxx>
Date: Wed, 31 Oct 2001 14:20:36 -0500 (EST)
On Wed, 31 Oct 2001, Erik Mooney wrote:

> 10/31/2001 12:43:49 PM, Chris Wilkson <ecwilkso@xxxxxxx> wrote:

> I've long been curious about the electrical mechanics of this.
> The book Video Demystified, well, didn't.

Yeah, I was pretty disappointed by that book.  It was very good for
people who are doing digital video, but I found it to be *very*
incomplete and hard to use for doing any kind of front end or back
end stuff, i.e. circuitry.

> beam.  But how does a vertical-hold knob figure in?

I don't know offhand.  But one guess would be that it just changes
the slope of the vertical deflection ramp generator in the receiver.
Err...a better way of saying that is that it changes the period of
the ramp.  Probably by changing the trippoint of the ramp.  If anyone
has a tv set with a v-hold knob, see if frobbing the knob affects the
spacing between the scanlines.  (I know the v-height knob does this.)

Another maybe more probable theory (given the v-height knob), is that
it affects the time constant of the v-sync filter in the receiver.
When I have some free time, I think I have a book that will tell me.


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