tony sayer wrote:

In article , William
Sommerwerck scribeth thus
That may be a different story because PAL TV sets never had them. NTSC
sets needed them because the phase of the color carrier wandered and
often shifted to the green, while PAL sets reset the phase each line
and
therefore were always "correct".

NTSC does not, and never had, an inherent problem with phase stability.

I cant conclude anything, but I know 2 things:
1. NTSC is widely known as Never The Same Color twice
2. The PAL system includes measures to counter phase shift causing
colour issues, so I can only conclude that the system engineers
thought this was a problem with NTSC.

I don't have the time to discuss this at length, but NTSC's unfortunate
reverse-acronym was the result of poor studio standards, and is not inherent
in the system. PAL incorporated phase alternation to partly compensate for
transmission problems (non-linear group delay) in Europe.


Wasn't something done to either the NTSC transmission spec or the sets
that largely alleviated that .. sometime after the original system
started?..


VIR was introduced decades ago. It inserted reference signals into
the vertical interval, near the start of each field of video. That
allowed automatic adjustment of the equipment, and eliminated the video
gain, black level, chroma gain, and phase controls that each operator
could adjust, to 'their' preference. NTSC wasn't the problem, it was
that everyone along the signal path could play with it. A system that
had VIR from the cameras to the transmitter had no problems. Of course,
that doesn't stop opinionated people from bashing a system they don't
understand.


--
You can't have a sense of humor, if you have no sense!