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http://HireMe.geek.nz/
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 Posted:
Sat Oct 02, 2004 6:02 am Post subject:
Origins of PAL: 1956 radio engeenering airticle from UK mag |
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Origins of PAL: 1956 radio engineering article from UK mag -- phase
alternations (and effects) considered...
I can't remember the exact magazine name, however.
HDTV's origins are easier to trace, but wavlet DTV seems to be nearly absent
from all technical literature.
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John Dyson
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| Posted:
Sun Oct 10, 2004 6:24 am Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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"http://HireMe.geek.nz/" <mikehack@u.washington.edu> wrote in message
news:cjl27h$eh8$1@gnus01.u.washington.edu...
| Quote: | Origins of PAL: 1956 radio engineering article from UK mag -- phase
alternations (and effects) considered...
Actually, phase alternation was considered by the NTSC team, but declined |
because of several technological problems at that time.
John |
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J.Michael Davison
Guest
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| Posted:
Sun Oct 10, 2004 2:20 pm Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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"John Dyson" <dyson@iquest.net> wrote in message
news:cka7e9$2p41$1@news.iquest.net...
| Quote: |
"http://HireMe.geek.nz/" <mikehack@u.washington.edu> wrote in message
news:cjl27h$eh8$1@gnus01.u.washington.edu...
Origins of PAL: 1956 radio engineering article from UK mag -- phase
alternations (and effects) considered...
Actually, phase alternation was considered by the NTSC team, but declined
because of several technological problems at that time.
John
I believe it was the delay-line technology that lagged behind everything. |
Size perhaps ? Remenbering how big the original Philips delay lines were in
early sets. I believe there was a picture of a delay line developed for the
SECAM system that was about 2 feet long in 'Wireless World' in the early
sixties.
Mike Davison |
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Paul Keinanen
Guest
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| Posted:
Sun Oct 10, 2004 3:20 pm Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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On Sun, 10 Oct 2004 11:20:23 +0100, "J.Michael Davison"
<mike@g1sbn.freeserve.co.uk> wrote:
| Quote: |
"John Dyson" <dyson@iquest.net> wrote in message
news:cka7e9$2p41$1@news.iquest.net...
Actually, phase alternation was considered by the NTSC team, but declined
because of several technological problems at that time.
I believe it was the delay-line technology that lagged behind everything.
|
You do not necessary need a delay line to receive PAL. In "Simple PAL"
used previously by some small portable receivers, the averaging was
done visually on the screen between adjacent lines.
When the Japanese TVs appeared on the European market in 1970s, they
"converted the PAL signal to NTSC" before decoding, to avoid some PAL
patent issues, apparently just inserted the PAL switch in front but
did not use the delay line.
So if the delay line was too costly for consumer electronics when NTSC
formalised the standard, the standard could have used phase
alteration, but only expensive second generation receivers would have
included this phase error cancelling a few years later.
Paul |
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Doug McDonald
Guest
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| Posted:
Sun Oct 10, 2004 7:24 pm Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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Paul Keinanen wrote:
| Quote: |
So if the delay line was too costly for consumer electronics when NTSC
formalised the standard, the standard could have used phase
alteration, but only expensive second generation receivers would have
included this phase error cancelling a few years later.
|
That's true, but a better way was used: intrinsically fix the
"problem" that PAL was designed to cover up with a kludge
solution.
The color problem for NTSC was fixed long before color sets
became big sellers. I bought a color TV set for our dorm
when I was in college in 1962, not my money of course.
This was a mid-level Heathkit set. It worked fine. The color
was quite accurate both for local originated material and
network material. You did have to adjust the "tint" control
as parts aged, but once a month or so was quite sufficient.
And, of course, semiconductors solved the problem
permanently and completely by allowing feedback circuits.
Doug McDonald |
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J.Michael Davison
Guest
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| Posted:
Sun Oct 10, 2004 11:47 pm Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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"Paul Keinanen" <keinanen@sci.fi> wrote in message
news:355im09vns1tgu1dufvurtsneeb9a4h75a@4ax.com...
| Quote: | On Sun, 10 Oct 2004 11:20:23 +0100, "J.Michael Davison"
mike@g1sbn.freeserve.co.uk> wrote:
"John Dyson" <dyson@iquest.net> wrote in message
news:cka7e9$2p41$1@news.iquest.net...
Actually, phase alternation was considered by the NTSC team, but
declined
because of several technological problems at that time.
I believe it was the delay-line technology that lagged behind everything.
You do not necessary need a delay line to receive PAL. In "Simple PAL"
used previously by some small portable receivers, the averaging was
done visually on the screen between adjacent lines.
|
True but no simple-PAL TV was ever manufactured in Europe for mass sale. If
I remember a Mullard lecture about the PAL system, the eye can
tolerate/average out a 20degree phase error. DeLuxePAL with a delay line can
correct for a 70degree phase error this being converted to an amplitude
error by the delay line so probably there would be noise apparent in the
chroma signals which is less disturbing visually than purple faces. A
5degree phase error was said to be noticeable in the NTSC system
| Quote: | So if the delay line was too costly for consumer electronics when NTSC
formalised the standard, the standard could have used phase
alteration, but only expensive second generation receivers would have
included this phase error cancelling a few years later.
|
Did I say anything about cost ? It probably did enter into it but glass
delay line technology didn't show its face until that 2feet long glass delay
line was produced for SECAM on which work began in 1956(ref Wikipedia) which
is 3 years after the NTSC system was set in stone.
Mike D. |
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Paul Ratcliffe
Guest
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| Posted:
Mon Oct 11, 2004 2:09 am Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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On Sun, 10 Oct 2004 20:47:48 +0100, J.Michael Davison
<mike@g1sbn.freeserve.co.uk> wrote:
| Quote: | You do not necessary need a delay line to receive PAL. In "Simple PAL"
used previously by some small portable receivers, the averaging was
done visually on the screen between adjacent lines.
True but no simple-PAL TV was ever manufactured in Europe for mass sale. If
I remember a Mullard lecture about the PAL system, the eye can
tolerate/average out a 20degree phase error.
|
You can see phase errors much less than that, which is why all broadcast
grade 1 monitors used to use simple PAL (we struggle to buy them with the
facility these days) - you want to see the phase errors so you can do
something to correct them.
| Quote: | DeLuxePAL with a delay line can
correct for a 70degree phase error this being converted to an amplitude
error by the delay line
|
This is rather misleading. Delay line PAL can cope with any error in
principle. The thing is, the bigger the error, the more SATURATION you
lose, not amplitude. It is a function of the cosine of the phase error,
so at 90 degrees you get black and white. At 70 degrees, you have lost
2/3 of your colour, which is rather noticeable.
| Quote: | so probably there would be noise apparent in the chroma signals
|
No there wouldn't. Visually there is probably less noise on the picture
because there is less noisy chroma signal.
| Quote: | which is less disturbing visually than purple faces. A
5degree phase error was said to be noticeable in the NTSC system
|
Indeed, and it is uncorrectable if it's a differential phase errro, which
is why NTSC is so crap. |
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Sal M. Onella
Guest
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| Posted:
Mon Oct 11, 2004 7:43 am Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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"Paul Ratcliffe" <abuse@orac12.clara34.co56.uk78> wrote in message
news:slrncmjcpl.rn.abuse@news.pr.network...
| Quote: |
Indeed, and it is uncorrectable if it's a differential phase errro, which
is why NTSC is so crap.
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"The pioneers take all the arrows." |
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R. Mark Clayton
Guest
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| Posted:
Mon Oct 11, 2004 7:30 pm Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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"Doug McDonald" <mcdonald@SnPoAM_scs.uiuc.edu> wrote in message
news:ckegbg$llt$1@news.ks.uiuc.edu...
| Quote: | Richard wrote:
Indeed, and it is uncorrectable if it's a differential phase errro,
which
is why NTSC is so crap.
snip
The NTSC system of that day DID require that the equipment with its
myriads of overheated vacuum bottles (and no feedback!) be kept
in tune ACTIVELY ... meaning that somebody had to check it. That was
the only actual problem ... PAL would have allowed sloppiness
to be covered up.
|
No PAL was designed so that such active adjustment was not required.
| Quote: |
But, of course, PAL was simply infeasible as a consumer
technology in 1950-1953 when color TV was developed ...
maybe
and we note, NOT developed by Europeans, who simply
adapted the ideas of the Americans (even, of course, SECAM,
which used a subcarrier and split luma-chroma rather than
actual RGB).
is this chauvinism or arogance? |
true the Europeans threw away their ten year lead by having a silly war, but
the first scheduled broadcast TV started on 1st October 1936 in London using
the Marconi electronic system - still the basis of all analogue broadcasts
today.
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Richard
Guest
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| Posted:
Mon Oct 11, 2004 9:07 pm Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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"Sal M. Onella" <salmonella@food.poisoning.org> wrote in message
news:qjnad.43031$a85.30507@fed1read04...
| Quote: |
"Paul Ratcliffe" <abuse@orac12.clara34.co56.uk78> wrote in message
news:slrncmjcpl.rn.abuse@news.pr.network...
Indeed, and it is uncorrectable if it's a differential phase errro, which
is why NTSC is so crap.
"The pioneers take all the arrows."
On worked on early RCA Color sets in 56 through 59, and some live broadcasts |
out of NYC on NBC such as the Bell Telephone Hour were perfection. Even
early CBS live color broadcasts direct from film of the Wizard of Oz were
absolute perfection. No color shift or phase shift and beautiful color that
would make your mouth water. Early color video tape inserted into live shows
were noisy and lacking in resolution. Sure, my first 17 inch Sony solid
state color set was the first "perfected" NTSC color set I saw, but it
simply could not reproduce color with the beauty and accuracy of those tube
based RCA sets. Changes in color saturation was an issue until some time in
the early 60's, from what I remember. Today NTSC simply does not suffer from
any of the issues PAL was designed to address.
Richard. |
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Doug McDonald
Guest
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| Posted:
Mon Oct 11, 2004 9:36 pm Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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Richard wrote:
| Quote: |
Indeed, and it is uncorrectable if it's a differential phase errro, which
is why NTSC is so crap.
On worked on early RCA Color sets in 56 through 59, and some live broadcasts
out of NYC on NBC such as the Bell Telephone Hour were perfection.
|
I did not own a color set until 1962, but two neighbors did, one of
thm dating from the day (actually, two days BEFORE) our NBC station went
all-color locally in 1954. That one was the station's weatherman,
and his son was in some of my school classes. I personally was there
and "on camera" when the station went color.
Even in 1954 the local programming in color was quite reliable.
The color was, as others have said, gorgeous.
Most live network programming as also OK, most of the time, though
admittedly there was the occasional offset of say 10 degrees.
Early color tape could be awful. Early local color telecines were ALWAYS
awful.
The NTSC system of that day DID require that the equipment with its
myriads of overheated vacuum bottles (and no feedback!) be kept
in tune ACTIVELY ... meaning that somebody had to check it. That was
the only actual problem ... PAL would have allowed sloppiness
to be covered up.
But, of course, PAL was simply infeasible as a consumer
technology in 1950-1953 when color TV was developed ...
and we note, NOT developed by Europeans, who simply
adapted the ideas of the Americans (even, of course, SECAM,
which used a subcarrier and split luma-chroma rather than
actual RGB).
Doug McDonald |
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J.Michael Davison
Guest
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| Posted:
Tue Oct 12, 2004 12:48 am Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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"Doug McDonald" <mcdonald@SnPoAM_scs.uiuc.edu> wrote in message
news:ckegbg$llt$1@news.ks.uiuc.edu...
| Quote: | But, of course, PAL was simply infeasible as a consumer
technology in 1950-1953 when color TV was developed ...
and we note, NOT developed by Europeans, who simply
adapted the ideas of the Americans (even, of course, SECAM,
which used a subcarrier and split luma-chroma rather than
actual RGB).
Eh ! |
ALL monochrome compatible colour TV systems use split luma-chroma with the
chroma carried by a sub-carrier system.
Monochrome compatibility was the cornerstone of NTSC, PAL and SECAM so black
and white TV owners were not denied a TV service. Frame sequential RGB
systems were not deemed to be compatible or practicable for that matter.
Mike Davison. |
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Doug McDonald
Guest
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| Posted:
Tue Oct 12, 2004 1:12 am Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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R. Mark Clayton wrote:
| Quote: |
The NTSC system of that day DID require that the equipment with its
myriads of overheated vacuum bottles (and no feedback!) be kept
in tune ACTIVELY ... meaning that somebody had to check it. That was
the only actual problem ... PAL would have allowed sloppiness
to be covered up.
No PAL was designed so that such active adjustment was not required.
Incorrect!! |
PAL, as a 1950's thing, if it were actually to have been
deployed, would have had the same technical problems
as NTSC, and would have required MORE tweeking to keep
working CORRECTLY. What it was designe to do was COVER UP
mistakes ... and in doing so, it lost saturation.
| Quote: |
But, of course, PAL was simply infeasible as a consumer
technology in 1950-1953 when color TV was developed ...
maybe
and we note, NOT developed by Europeans, who simply
adapted the ideas of the Americans (even, of course, SECAM,
which used a subcarrier and split luma-chroma rather than
actual RGB).
is this chauvinism or arogance?
true the Europeans threw away their ten year lead by having a silly war, but
the first scheduled broadcast TV started on 1st October 1936 in London using
the Marconi electronic system - still the basis of all analogue broadcasts
today.
|
Uh ... perhaps you might take reading comprehension lessons?
I said COLOR TV.
In any case, electronic TV per se was developed in parallel
in Europe and the US. After WWII, of course, the US simply
annihilated Europe in the deployment of TV. Until Europe
got cable and satellite, most people there had FAR fewer stations to
watch than people in the US did. England had only ONE
TV "network" at a time when my hick town in Texas had three networks
and one independant station.
And Europe is STILL seriously backwards ... you have no HDTV,
for example.
Doug McDonald |
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Paul Ratcliffe
Guest
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| Posted:
Tue Oct 12, 2004 3:24 am Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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On Mon, 11 Oct 2004 16:12:02 -0500, Doug McDonald
<mcdonald@SnPoAM_scs.uiuc.edu> wrote:
| Quote: | After WWII, of course, the US simply
annihilated Europe in the deployment of TV. Until Europe
got cable and satellite, most people there had FAR fewer stations to
watch than people in the US did. England had only ONE
TV "network" at a time when my hick town in Texas had three networks
and one independant station.
|
So what? It's not quantity but quality. But that is something you
Americans will never understand, even if you lived to be 1000.
| Quote: | And Europe is STILL seriously backwards ... you have no HDTV,
for example.
|
Our content is much better than yours, but alas it is rapidly heading
towards the same dreadful standards that you enjoy. 5000 channels of
crap. Great, just what I need. |
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Alan
Guest
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| Posted:
Tue Oct 12, 2004 6:20 am Post subject:
Re: Origins of PAL: 1956 radio engeenering airticle from UK |
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In article <slrncmm5h9.31t.abuse@news.pr.network> abuse@orac.clara.co.uk writes:
| Quote: | On Mon, 11 Oct 2004 16:12:02 -0500, Doug McDonald
mcdonald@SnPoAM_scs.uiuc.edu> wrote:
After WWII, of course, the US simply
annihilated Europe in the deployment of TV. Until Europe
got cable and satellite, most people there had FAR fewer stations to
watch than people in the US did. England had only ONE
TV "network" at a time when my hick town in Texas had three networks
and one independant station.
So what? It's not quantity but quality. But that is something you
Americans will never understand, even if you lived to be 1000.
|
Indeed, quality counts. That is why we prefer NTSC, which is a better system
once the base technology is able to deal with its needs.
Indeed, quality counts. With motion (and that is what Television is about,
after all), the quality of NTSC is clearly better, and the U.S. HD standards
are even better.
| Quote: | And Europe is STILL seriously backwards ... you have no HDTV,
for example.
Our content is much better than yours, but alas it is rapidly heading
towards the same dreadful standards that you enjoy. 5000 channels of
crap. Great, just what I need.
|
Indeed. Four years ago in the U.K., I had the amusement of watching
an old episode of Quincy M.E. -- a U.S. program.
Hollywood squares with children in the squares. Wheel of Fortune with
a set that looked put together on a $100 budget.
Didn't look like quality, nor did it look original. But it was fun
to watch.
Alan |
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