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isw

In article ,
wrote:

"If you're talking about PAL, which came later, quite good arguments can
be made that it's not better at all; just that its weaknesses are in
different places."

Well for one they eliminated the phase control. On US sets it was called the
tint or hue control and it shifted the phase of either the chroma subcarrier
or the oscillator. Their little scheme cancelled out the errors, which were
mainly caused by poor frequency response which would shift the phase of the
burst or even make the PLL in the TV have a phase error because part of the
burst is cut off. However it happened, you sometimes needed to adjust the
tint in the old days.

The Phase Alternation dropped the lowest interlace rate from NTSC's ~15
Hz to ~6.25 Hz, which is really visible and was responsible for PAL's
well known "high brightness flicker".

Also, PAL was more lines. I think it was 50 Hz which would mean they needed a
longer persistence phosphor. Also the horizontal rate was faster. They had
quite a bit more resolution bt at the cost of frame rate.

Higher spatial resolution, lower temporal resolution. Probably a wash.

But that can be dealt with, you know movies in the theaters only used to be
24 frames per second right ?

Actually, 48 FPS as projected -- each frame was shown twice.

Well people did not really have a problem with
that. They only reason it is a problem with a CRT is because the picture is
drawn in a series of lines and that makes it more visible.

It's actually just because it's a much lower rep rate. See my comment on
PAL's interlace problem. A longer persistance phosphor would have helped
the flicker problem, but would have caused motion blur.

Isaac