Then the OP should've been to alt.corp.akai, alt.corp.sony, alt.corp.toshiba, alt.corp.jvc, alt.corp.nec, alt.corp.hitachi, alt.corp.sharp, alt.corp.panasonic , etc.
Not to sci.electronics. *repair*
And PHIL = PLEASE HELP I'M LOST!!
...heh
-- Live Fast, Die Young and Leave a Pretty Corpse
That isn't immediately clear to me. How badly would pahse alteration affect the frequency components of the subcarrier?
You left out 3.5. The I and Q primaries' color and bandwidth are based on how the eye actually perceives color. NTSC not only transmits more color information, but uses the available bandwidth more effectively.
Actually, most early sets (at least RCA) had full-bandwidth color. RCA continued to offer such sets for two or three years. I suspect many current sets using digital processing are full-bandwidth, but there's no easy way to know which is which.
Not that I'm aware of. Such sets require a second delay line, which runs up the cost.
Correct.
Oh? Why?
1) They were stuck with the smaller color gamut because of the color primary choices used in the encoding. 2) They could not use wide bandwidth decoders because the chroma encoding was equal bandwidth. 3) Comb filtering in PAL is not nearly as effective since the chroma components are 'smeared' out rather than tightly interleaved between the main luminance components. The phase alteration and the 25 Hz offset of the chroma carrier in PAL (look up Hannover bars) kills the effective use of comb filters.Your point 3.5 is well taken. Regarding the second delay line, the extra delay needed in the I channel was just a simple lumped component all pass filter that could be fabricated at very low cost. I also remember the time when early VCRs actually included the NTSC pre-distortion phase compensator that was part of the broadcast standard to compensate for the nonlinear delay of the IF stages in the receivers. The theory was that you pay only once in the broadcast encoder rather than in every TV set. I actually bought a few of these on the replacement part market to use in other video projects for about $1.00 each. It was a passive module with three leads containing a few inductors and capacitors. I installed one in a RF modulator I had and they sure eliminated the chroma smear and sharpened up the luminance. It is interesting that even with SAW IF filters which could have been made with uniform group delay, they are fabricated to reproduce the delay characteristics of the older tuned inductor-transformer IF amplifiers.
David
How odd to come across you in a group other than SCJM!
Never heard of Hanover bars. (Though I've lived in PA, I've never been in any, either.) I didn't realize PAL had this basic problem.
Which is one of the problems with SECAM. Transmitting only one color signal per line simplifies encoding and recording (at the studio) at the expense of a more-expensive receiver.
This, also, is new to me. I'd always assumed there was no correction in one part of the system for errors in another.
"Geoffrey S. Mendelson" wrote in news: snipped-for-privacy@cable.mendelson.com:
when I was at TEK,I used to have a chart with all the worlds TV systems,and their differences. I tossed all that stuff when I was laid off,didn't have room for all the stuff I'd have kept if I could. I repaired and calibrated TEK NTSC and PAL video test equipment.I did a little bit of digital video,and -one- SECAM unit,so I won't claim any expertise with SECAM.
-- Jim Yanik jyanik at localnet dot com
"Geoffrey S. Mendelson" wrote in news: snipped-for-privacy@cable.mendelson.com:
Which really didn't matter,as the program sources varied widely in color accuracy.
*VIRS* was the VITS signal meant for autocorrection,but it wasn't used much IIRC.VIRS = vertical interval reference signal VITS = vertical interval test signals.
-- Jim Yanik jyanik at localnet dot com
"William Sommerwerck" wrote in news:igc78f$66b$ snipped-for-privacy@news.eternal-september.org:
They got their video from a number of different sources,who also didn't put much effort into correct color.
Likely the addition of VIRS circuitry.
-- Jim Yanik jyanik at localnet dot com
-- I bought a PAL DVD set from Australia (I'm in Canada), and took a chance since many NTSC players are able to play back PAL. My LiteOn, Toshiba, and Apex DVD players are all able to play it back, while my Samsung and Pioneer give 'error' messages. You may find that some cheap import players almost always play PAL *and* NTSC DVDs.
True. US receivers use the VIR (Vertical Interval Reference) on line
20 for chroma phase correction to automagically correct both static and differential phase errors. I think this started in about 1980.In a past life, when I was doing video, it meant "Now That Seems Crazy", "Nobody Thinks Such Crap", or "Nail Through Some Coax".
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
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WHO CARES? Analog is thankfully gone.
G=B2
snipped-for-privacy@cable.mendelson.com:
ch
Thanks for that. In knew I was using the wrong term but I haven't worked in a broadcast station since '85. The CBS affiliate in Madison WI had the Tektronix VIRS corrector for the incoming network feed. One of the engineers modified it to compensate for blacks below setup. The only FCC citation the station got in 30 years was from the black level on the CBS show 'The Price Is Right' when they spin the wheel.
G=B2
What error message. I'll bet it was "incorrect disk", or something related to region code, not because it was PAL.
Geoff.
-- Geoffrey S. Mendelson N3OWJ/4X1GM Those who cannot remember the past are condemned to misquote it.
The problem was that there were too many places in the system to adjust the phase, and no way to match the phase of multiple sources outside a single studio. The coaxial & microwave relays used by TV networks needed amplifiers and correction circuits at regular intervals. Every location required the careful adjustment of all parameters so a usable signal was availible at the other end. I freind of mine worked ATT longlines back then and told me what a PITA it was to keep the system working properly. Not only was there a master E_W feed, but most of it could be rerouted around an outage, even if the phasing didn't match. that was the reason that ATT was able to quickly piece together a nationwide feed to all network TV stations, no matter which network on the day JFK was killed.
store.
one of the problems with the cheap Tvs were that people would play with the settings. Some people liked everyone to look like they were wearing clown makeup. Or as one idiot put it when i told him not to toch one of our TVs, "If I'm buying a color TV, I want all the color I can get!" :(
-- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated.
William, Phil is a mentally ill Aussie who rarely takes his medicine. Just ignore him.
-- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated.
Pathetic Halfwit Infecting Lambs.
-- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated.
Early TVs often had a faint hum bar in the vertical. By being locked to the line frequency, it was fixed to one location, and most people never saw it.
-- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated.
Why? Dish or Direct supply all the equipment and install it, just like the various CATV companies.
So, you think someone should be able to us one company's equipment to steal service from another?
-- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated.
Really? Entire chipsets were made to use it and they reduced the cosst to build new TVs. Just because it wasn't etched on the CRT's face doesn't mean it wasn't used.
-- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated.
There were no 'digtially encrypted HBO satellite receviers' in 1983. An external 'Video Chiper II' was used with recievers on a small list that were tested to work with the 'Video Chiper II'. Most commercial grade C-bnad receivers had a low pass filter in the video amplifier that prevented them from working. The interesting thing was that the cheaper equiment that was barely better than consumer grade made up most of that list. United Video Cablevision in Cincinatti, Ohio was one of the systems picked to do field testing before the system went live. I modified all our Collins-Rockwell receivers to work with the 'Video Chiper II' test units. They freaked out when I sent them the test data and told them what hardware I was using. BTW, the test unit serial number was 16.
It wasn't until combo consumer grade recievers wer built that the 'Video Chiper II' was changed into a plug in module so it could be replaced or upgraded as the securtiy software changed.
Also, note that the original 'Video Chiper' was full digial scrambling built for the military, while the 'Video Chiper II' digitized the audio and inverted the sync on the video. VC units cost over a million dollars each. HBO wanted a way to turn off the feed to CATV systems who were late, or didn't even try to pay thier bills. A well known MSO in the early '80s was over six months behind on everything except their payroll and utility bills. HBO wanted to make them catch up, and stay that way.
-- You can't fix stupid. You can't even put a band-aid on it, because it's Teflon coated.
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