You've sort of answered your own question, with a slight error. If you
have colors 1-15, there are only 14 gaps between them. So a properly
adjusted machine with d=24 degrees gives a total of 336 degrees...no overlap.
Now the answer to the delay question. If you have a choice between
a signal (color 1) and a delayed form of itself (color 15), the second
one will be delayed, no? :)
Seriously, a picture might help. Below, I've drawn a few periods of
a sinewave. Each period corresponds to one pixel on screen. I've
assumed that the delay for color 15 is 360 degrees, so that it lines
up with color 1. For colors 2 and 3, you can see the delay building up.
For color 15, the delay is an entire pixel displaced.
- - - -
/ \ / \ / \ / \
/ \ / \ / \ / \ color 1
\ / \ / \ / \ /
\ / \ / \ / \ /
- - - -
- - - -
/ \ / \ / \ / \
/ \ / \ / \ / \ color 2
\ / \ / \ / \ /
\ / \ / \ / \ /
- - - -
- - - -
/ \ / \ / \ / \
/ \ / \ / \ / \ color 3
\ / \ / \ / \ /
\ / \ / \ / \ /
- - - -
(...colors 4-14......)
- - - -
/ \ / \ / \ / \
1 pixel / \ / \ / \ / \ color 15
<-------> \ / \ / \ / \ /
delay \ / \ / \ / \ /
- - - -
- - - -
/ \ / \ / \ / \
/ \ / \ / \ / \ 1 pixel color 1
\ / \ / \ / \ / <------->
\ / \ / \ / \ / delay
- - - -
This is clearly visible on a real display. It's what causes the artifacts
at vertical edges. No big deal, but it's important to keep in mind when
putting similar colors next to each other.
-Chris
On Thu, 14 Jul 2005, Eric Ball wrote:
> From: "Chris Wilkson"
>
> > It is possible to make the delay too large, so that the phase delay
> > for color 15 is equal to or more than 360 degrees. When the delay
> > equals 360 degrees, the effect is that color 15 = color 1 = gold.
> > But there will be a 1 pixel delay to the right for color 15. If the
> > phase is > 360 then color 15 could be equal to color 2, 3, etc...
>
> Umm, why would there be a delay? Inside the TIA the colors are simply taps
> along a delay line which the colorburst signal travels down. This is a
> continuous process so at any instant color 1 = phase p, color 2 = phase p +
> d, color 3 = phase p + 2d, etc. So if d = 24 degrees then the phase of
> color 1 and color 15 will match.
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://stella.biglist.com
