[opendtv] Re: PAL
- From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 14 Dec 2006 14:52:55 -0500
The great looking pictures in PAL are in large part owing to the care
exercised during production.
The problem PAL was designed to overcome was the problems with piping
composite video over telephone lines. Broadband telephone lines were much
better in the US than in Europe at the time TV was beginning to be broadcast
in color. Remember we were only a decade or two after WWII. A former
laboratory partner of mine at David Sarnoff Research Center, John Ober
Schroeder, developed a device popularly referred to as the "Schroeder
shredder" for the measurement of broadband telephone lines when he worked
for NBC labs. It caused great gnashing of teeth at AT&T.
John was a very good engineer and was self-taught, never having attended
college. We collaborated on some early stereo FM receiver designs for RCA.
This was before I designed the count-down stereo decoder using the
integrated-circuit counter designs of Borys Zuk, who later developed the
decoder into a commercial product while I tripped of to law school.
The extra complication of PAL made frame storage more complex, and it became
a minor hindrance when better telephone lines became available. I recall
Doctor Brown saying in passing that phase-line alternation had been
considered by NTSC early on, but was decided against as being unnecessary.
There may be some of the really aged ORCAs around that know more about this.
I was just a Wunderkind at the time and my section of the Industry Service
Lab was chiefly concerned with radio, rather than TV. Later on I shared the
old TV studio at DSRC with Ray Kell, working on exotic display technologies.
Al
----- Original Message -----
From: "Dale Kelly" <dalekelly@xxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Thursday, December 14, 2006 1:30 PM
Subject: [opendtv] Re: Delay
>
> John W. wrote:
>
> > Well, we DO have a working modulation scheme, which replicates NTSC,
> >which was never an optimal way of transmitting analog video.
> >PAL was subsequently developed and was ALWAYS better than NTSC,
> >using a simple technique that reversed by 180 degrees alternate lines.
> >An elegant improvement over NTSC.
>
> Our eyes clearly do not deceive us; when visiting Europe we do see an
> obviously superior analog television picture. However, PAL is not the
source
> of this superiority. The reality is that PAL actually somewhat degrades
the
> overall image quality and the problem it was designed to resolve (Color TV
> set Hue inconsistencies) was resolved by TV set manufacturers over twenty
> years ago .
>
> The source of this superior "PAL" picture is actually the additional 25%
> bandwidth allocated to that signal and an additional 100 vertical scan
lines
> used per frame. If Europe were today transmitting NTSC with those same
> parameters we would see at least as good a picture as we do with PAL.
>
>
>
>
>
>
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