Why is video inverted for transmission?

[Gene E. Bloch]

Randy Yates wrote:

...


Pro: before. Gnosis: knowing. Literally, "knowing before". Practically,
prediction. You need a better dictionary, but the context in which the word
showed up here would have given me no hint either.

Jerry

It would have been in Randy Yates's dictionary if it had been spelled
"prognostication". Perhaps that is what Randy meant, in his subtle way

 

[Randy Yates]

It would have been in Randy Yates's dictionary if it had been spelled
"prognostication". Perhaps that is what Randy meant, in his subtle way

I did find prognostication, but since its definition deals with
predicting the future, and that definition didn't make sense, I
decided to simply ask for clarification rather than attempting to
second- and third-guess what he meant.

Is that being subtle? Is it playing a game (i.e., "being subtle") to
ask that wording be spelled correctly and make sense?
--
% Randy Yates % "The dreamer, the unwoken fool -
%% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..."
%%% 919-577-9882 %
%%%% <[email protected]> % 'Eldorado Overture', *Eldorado*, ELO
http://www.digitalsignallabs.com

 

[Gene E. Bloch]

I did find prognostication, but since its definition deals with
predicting the future, and that definition didn't make sense, I
decided to simply ask for clarification rather than attempting to
second- and third-guess what he meant.

Is that being subtle? Is it playing a game (i.e., "being subtle") to
ask that wording be spelled correctly and make sense?

Would it have been easier for you if I had said "in his gentle way"
instead? Did the emoticon not help you interpret my intent?

 

[Bob Myers]

I just don't know. The ambition of the multiplex operators here
appears to be simply to cram as many programmes on as the mux will
carry. There are no sharp programmes on our digital service.

That's unfortunately been the trend in the U.S. as well, at
least as far as digital cable/satellite providers are concerned.
I get horrible compression artifacts on many programs via
the digital satellite service.

What does the digital over-the-air broadcast picture look
like for you, though?

Bob M.

 

[Allen]

"Richard Crowley" writes:
[...]
How easy it is for us to do arm-chair engineering here 50+
years after the original development *with the technology of
the day*! This entire "discussion" reeks of revisionism and
has turned just completely silly.
Richard, don't look now, but your old-fartness is showing.

Forgive me if I would rather take the word of the people
who actually did it over a bunch of prognostigations from
random Usenet users 50 years after the fact.

I don't recall challenging anything the original designers said or
developed, unless Michael Terrell is one such person.

What does "prognostigation" mean? I can't find it in my dictionary.

Try "PrognostiCation", or "PrognostiCate". Of course, if you looked up
the original spelling you would have seen this immediately the blank
space that you looked at, so you have probably identified yourself as a
troll.
Allen

 

[Michael A. Terrell]

JosephKK wrote:

(snip)


I suppose I was always surprised that gamma correction was noticed
in the first place, but I suppose it is.

I believe that NTSC did tests to show that it wouldn't be a
significant problem. Probably also expecting most people
to switch to color sets.

-- glen

There was no color TV when the NTSC standards were written.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

Guys, it was a joke ...

Who cares about all that drift if the programming ain't worth watching
in the first place?

Its no joke if it was your job to deliver the best video possible.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

Yes, but then they make us pay around $50/month where $49 of those
Dollars are going towards junk I don't care for. Luckily there is the
VCR. Occasionally our video rental place in town has an old movie. Much
of that has never even been ported to DVD.

Check the dollar stores. Lots of old movies on DVD for a buck, and
every batch they get is different.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Rich Grise]

Joerg [email protected] posted to
True, but a lot of the best stuff is B&W (notably much of Andy Griffith,
Bonanza, The Outer Limits, Masterpiece Theater, and so on). Often a lot of
the old good stuff is available on cable or satellite that OTA stations
cannot use because the audience is too small.

We have a couple of local indies here in So. Cal that show reruns of old
classics:
http://www.kdoctv.net/schedule.htm
http://ktla.trb.com/entertainment/?track=nav

Cheers!
Rich

 

[Rich Grise]

The demand won't really start until people are forced to stop using their
analog tuners. At that point, people will have at least three options:
continue to use cable or satellite with a box that outputs analog (these
people incur no new costs), buy a digital TV, or buy a digital tuner.

4: Riot in the streets.

Cheers!
Rich

 

[Randy Yates]

Did the emoticon not help you interpret my intent?

No. I still don't know what your intent is or was.
--
% Randy Yates % "The dreamer, the unwoken fool -
%% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..."
%%% 919-577-9882 %
%%%% <[email protected]> % 'Eldorado Overture', *Eldorado*, ELO
http://www.digitalsignallabs.com

 

[Don Pearce]

That's unfortunately been the trend in the U.S. as well, at
least as far as digital cable/satellite providers are concerned.
I get horrible compression artifacts on many programs via
the digital satellite service.

What does the digital over-the-air broadcast picture look
like for you, though?

Bob M.

It looks soft, bad motion artifacts - the Rugby World Cup coverage at
the moment frequently verges on the unwatchable. Colours are often
"painting by numbers" type pastel shades. Flesh tones particularly
suffer from this.

d

 

[Michael A. Terrell]

I worked on an old experimental 441-line TV transmitter that used metal
tubes. The designer -- damn him -- needed one more tie point than the
birdy boards had, and used socket pins connected to the shells of
several of the tubes. It was grounded for RF, but put 400V on what one
ordinarily would expect to be grounded.

That's why the tube databooks listed those pins and N/C. N/C = DO
NOT USE.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Randy Yates]

"Richard Crowley" writes:
[...]
How easy it is for us to do arm-chair engineering here 50+
years after the original development *with the technology of
the day*! This entire "discussion" reeks of revisionism and
has turned just completely silly.
Richard, don't look now, but your old-fartness is showing.
Forgive me if I would rather take the word of the people
who actually did it over a bunch of prognostigations from
random Usenet users 50 years after the fact.

I don't recall challenging anything the original designers said or
developed, unless Michael Terrell is one such person.
What does "prognostigation" mean? I can't find it in my dictionary.

Try "PrognostiCation", or "PrognostiCate". Of course, if you looked up
the original spelling you would have seen this immediately the blank
space that you looked at, so you have probably identified yourself as
a troll.

Allen,

Is it that satisfying to you to sit behind your computer and write
nasty little messages like this to total strangers?

If you would read the adjacent post I made on this very subject
a few minutes ago, you would see my reasoning.
--
% Randy Yates % "Remember the good old 1980's, when
%% Fuquay-Varina, NC % things were so uncomplicated?"
%%% 919-577-9882 % 'Ticket To The Moon'
%%%% <[email protected]> % *Time*, Electric Light Orchestra
http://www.digitalsignallabs.com

 

[Michael A. Terrell]

Michael A. Terrell wrote:

...


I once built a transmitter with a pair of water-cooled 6L6s. I cut away
the outer metal sleeve, exposing a smaller glass envelope than that of a
a glass 6L6. The tubes were the only components mounted on the outside
of the chassis. The plan had been to place the chassis upside down over
a bucket of light oil, but we never got the oil, so we used water
instead. The "bucket" was actually a gallon jug with the top cut off. We
could see the plates glow through the glass. We ran half a KW, replacing
the water as it boiled off.

You should have seen some of my projects, years ago. I'm still
using one of them: An adjustable battery charger build from a RV power
supply, and a Staco version of a Variac. The output voltage is
adjustable from zero to about 20 volts, and lets you set the charging
current. It is built in the aluminum housing of a WWII aircraft RADAR
receiver.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

"JANA" wrote ...

And the latest computer screens (including laptops) are switching
back to the very shiny surface apparently because the "non-glare"
treatment also reduces the clarity of the image you are viewing
from the screen.


Some of that may have been from the thick glass envelope
over the front of the screen. Most glass looks slightly greenish
under conditions where you can see the glass itself vs. whatever
is on the other side.


Indeed, one of the many psychological effects that modern
technology depends on to interface with humans.

The glass is green from the lead, used to reduce Xray emissions.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Richard Crowley]

The glass is green from the lead, used to reduce Xray emissions.

But even "regular glass" appears to have a greenish tint.
Like the mirror in my bathroom. If you look at it from an
acute angle, you can seee the greenish cast from the glass.

 

[Jerry Avins]

It would have been in Randy Yates's dictionary if it had been spelled
"prognostication". Perhaps that is what Randy meant, in his subtle way

No wonder Thunderbird's spell checker flagged it. I assumed the word was
just too big. Silly me!

Jerry

 

[Michael A. Terrell]

At first I wanted to agree with you - it makes sense in one way.

But a sync pulse is really nothing more than the horizontal scan rate,
right? You can build a PLL to pull this way out of the noise by making
a very narrow-band loop filter. The video information is a different
matter since you need a wide bandwidth to utilize it.

So I'd say the sync pulse power can be lower than the video power, by the
ratio of the bandwidths, and still be appropriate for a usable video signal.

Sigh.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

Randy, back when TV first went commercial, a frequency divider was a
multivibrator with a little of the pilot signal introduced somewhere. It
wasn't possible to make large divisions stably, so cascades of smaller
divisions were used. RCA's original system used 441 lines -- I assume
you know about odd line count and interleave -- and synced horizontal to
vertical with two divisions by 7 and two by 3. The FCC, guessing that
CRTs larger than ten inches would eventually come, insisted on 525. That
factors to 5x5x7x3. Don't confuse what is easy today with what was
practical using tubes and discrete components. The original TV sync
circuits were designed when the Eccles-Jordan bistable was a novelty.

Don't forget that a tube based sync generator could fill almost half
a relay rack in the early days. (The power supply chassis took the rest
of that half rack space.) A TV station I visited in Fairbanks Alaska
was still using one in 1974. The military TV station I worked at at
that time had a state of the art RTL IC DUAL sync generator, with an
automatic transfer that didn't use all of three rack units. (5.25")
Even with two power supplies, there were still a few empty slots.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida