Was wondering if VIR, implemented to its full potential, have eliminated the Tint control?

That (as well as saturation control) was the idea.

It was not at all the same system as PAL, in which the red-minus-white (R-Y) switched with each horizontal scanning line. In NTSC with VIR, every line of the actual picture was transmitted exactly as had been done for the coverage of the 1954 Tournament of Roses Parade. The difference was one line in the vertical retrace interval, a consistent reference signal the a TV set would use to automatically set the hue and saturation perfectly - to the Vertical Interval Reference - VIR.

I really don't know why it didn't catch on. I can only wonder if its promotor wanted too much money for the patent royalty? was the inventor an outsider? (see interval windshield wipers), did TV manufacturers believe their products produced fine color anyway?, was NTSC color reliable enough by the time VIR came around that setting the dials just once was enough to assure good color? Did the entertainment industry want any improvement in picture quality to be tied to selective availability and copy blocking?

...

I really don't know why it didn't catch on. ...

The reason it didn't catch on is that the local stations started using it to close the loop on their transmitter adjustments by inserting it locally. Of course, when they did that, it no longer bore any fixed relation to the original video, just as the locally re-inserted color burst didn't either. So, set manufacturers decided not to use it, as it often made the color worse instead of better. It could have succeeded if GE had managed to get the FCC to mandate its correct use.

EDit: By the way, GE was the inventor and promoter.

The reason it didn't catch on is that the local stations started using it to close the loop on their transmitter adjustments by inserting it locally. Of course, when they did that, it no longer bore any fixed relation to the original video, just as the locally re-inserted color burst didn't either. So, set manufacturers decided not to use it, as it often made the color worse instead of better. It could have succeeded if GE had managed to get the FCC to mandate its correct use.


Do you mean they (stations) used the actual VIR format for transmitter monitoring, or just snatched the assigned lines for similar test signals?

Do you mean they (stations) used the actual VIR format for transmitter monitoring, or just snatched the assigned lines for similar test signals?

Yes, they used the actual VIR format, newly inserted. They had to, for material that didn't contain it originally, and then just did it for all material.

...when they did that, it no longer bore any fixed relation to the original video, just as the locally re-inserted color burst didn't either.

Though I'm no expert on VIR, wouldn't locally regenerated (network sourced for instance) burst have precise phase lock to the original and, by extension, the VIR (regenerated?) bursts.

So I'm guessing from this the networks used VIR with their feeds?

Though I'm no expert on VIR, wouldn't locally regenerated (network sourced for instance) burst have precise phase lock to the original and, by extension, the VIR (regenerated?) bursts.

So I'm guessing from this the networks used VIR with their feeds?

Not sure if I understand your question completely.

The local burst must be reinserted to standard amplitude and clean waveform per FCC rules. Therefore, it at least loses its relation to the chroma amplitude, which may have changed due to analog transmission distortion over the network. In practice, the reinserted phase is also adjustable and therefore can be misadjusted. If there is significant phase distortion of the chroma over the network, the phase of the incoming burst may also vary over its width, making it difficult to know where to set the phase of the re-inserted burst. The VIR reference had a much wider burst of chroma during the active line, which was supposed to fix this by ignoring edge distortions. Unlike NTSC, the PAL burst, by alternating phase sequence from line to line, should average out to the correct phase even when phase distortion is present.

The whole idea of VIR was to insert it at the originating studio and not replace it anywhere along the chain, not even at network central control; but not every program had it inserted.

I would note that VIR, occurring once per field, had a much slower control action than color burst, and could not possibly compensate for fast signal variations like airplane flutter.

Another note regarding the mismatch of re-inserted burst to chroma amplitude distorted by network transmission:

The two major US TV makers, Zenith and RCA, had different philosophies in this regard.
Zenith used the burst as automatic color level reference, as this took out the final transmission variations due to ghosts, airplane flutter, etc. However, this ignored the network distortions. RCA's auto color mode worked on the average chroma level of the picture. They felt this was an overall improvement, although it meant the color level could be affected adversely by overcompensating for scenes either with large areas of bright colors or with no saturated colors. The general public seemed to be accepting of these "subject errors." They bothered me, though, and I always preferred to run the RCA sets with auto color off for this reason. Unfortunately, this meant also losing RCA's superior auto hue ("tint") correction, which actually had been invented by a colleague of mine at Motorola and was licensed to RCA. It worked only on hues near flesh tone, and didn't destroy greens and purples the way other makers' auto tint did. Motorola, by the way, never used their own invention.

It was originally required by the FCC for remote controlled transmitter stations. The studio had a Tektronix 147 inserter which stripped anything that was already on line 19 and insert the vir. The output fed the STL. At the transmitter there was a Tektronix 1440 which looked at the inserted vir and controlled luma, color and phase.
I remember there was a non-remote station that never had anything in the vertical interval. They even stripped the network vits.
We later upgraded the studio to the Tektronix 1910 which had GCR. We got calls from cable companies if the GCR was malfunctioning.

..RCA's superior auto hue ("tint") correction, ...worked only on hues near flesh tones.

How on earth did this work?

How on earth did this work?

The usual auto tint worked by changing the angles, and possibly the gains, of the color demodulators. The result was a reduction in saturation of greens and magentas, plus colors that were near orange or cyan had any green or magenta component reduced. If you picture a circular color wheel (or a gated-rainbow test pattern), the circle got compressed into an ellipse.
Thus, all colors were distorted to be closer to flesh tone or cyan, or at least a weaker green or purple.

The RCA circuit worked on the phase of the oscillator output going to the demodulators. The nearer the chroma phase was to flesh tone, the more strongly it was pulled towards flesh phase (hue). If it was already a flesh hue, this made no difference. If it was close, it was pulled strongly towards flesh. If it was further away, it was pulled less. So, yellows were made a bit more orange, but greens weren't significantly changed. Similarly, reds were pulled toward orange-red, magentas were pulled a bit towards red, but purples were changed even less if at all. Since this change was phase only, it didn't affect the saturation of greens, purples, or any color, for that matter.

That is interesting how it worked.
Instead of all that effort, they should have - like you said - lobbied to mandate VIR for all transmissions as VIR decoder no more complex - and much better - than Auto Color?

That year did Auto Color appear?
What year did networks abandon VIR?

VIR was required till the end of analog transmission. The ONLY set I ever remember that utilized it was a 19 inch GE that was installed at a station I worked at in '77 in SC.
And I remember seeing a Sylvania that used the GCR in the 90's.

I know someone with a VIR set that has a gassy CRT.

The lack of set manufacturer adoption led many broadcasters to think these signals had another purpose. By putting test signals in the vertical interval, it allowed the FCC to evaluate your transmitters performance that they couldn't do with just program video.
While most VHFs kept the "house" clean, many UHFs were barely staying on the air.
I had heard that some stations were fined for excessive group delay and others recieved warnings.

Speaking of UHF, I got in an auction, one of the RF modulators used at one of the UHF stations in the area. Among a weird coaxial baseband video input, it also has the emergency broadcast inputs too. And when I got it, it was still set on the frequency that the station aired, it was never messed with.

I know someone with a VIR set that has a gassy CRT.

My parents bought a GE 25" console with VIR new in '77. Lasted until '83. Been looking for a VIR equipped set for many years and never found one.

My parents bought a GE 25" console with VIR new in '77. Lasted until '83. Been looking for a VIR equipped set for many years and never found one.

His is a 19" GE...I don't know if he would sell it, but I could check.

So I'm guessing VIR has nothing to do with the auto color button on my TV?

VIR was required till the end of analog transmission. The ONLY set I ever remember that utilized it was a 19 inch GE that was installed at a station I worked at in '77 in SC.
And I remember seeing a Sylvania that used the GCR in the 90's.

That's what I thought, only really seen it on the GE 19" with that red VIR light on controls panel. What a pity as VIR was a brilliant innovation

=old_tv_nut;3170654
The local burst must be reinserted to standard amplitude and clean waveform per FCC rules. Therefore, it at least loses its relation to the chroma amplitude, which may have changed due to analog transmission distortion over the network. In practice, the reinserted phase is also adjustable and therefore can be misadjusted. If there is significant phase distortion of the chroma over the network, the phase of the incoming burst may also vary over its width, making it difficult to know where to set the phase of the re-inserted burst. The VIR reference had a much wider burst of chroma during the active line, which was supposed to fix this by ignoring edge distortions. ..
The whole idea of VIR was to insert it at the originating studio and not replace it anywhere along the chain, not even at network central control; but not every program had it inserted...



Some great info there!
Brilliant of General Electric to have a wider burst in active line - and at a luminance level of a typical flesh tone!

So, to me, the "problems" would have been easily avoidable with good broadcasting practice:
For example source material with VIR needed to be first reclaibrated thru a professional VIR processor
that also regenerated burst & VIR (with exact phase similitude) to the gated line 19 sample).
Was there such an instrument?

I remember quad videotapes (2 inch) coming in that had a sticker saying "Protected by VIRS- adjust proc amp to pass."
In reality burst and sync got "regenerated" 2 times. After leaving the switcher it went to a proc amp where it would get black and white clip and agc. (I thought the best AGC amp was the RCA TA19. You could always tell a station that had one of these on the air.) Sync and burst would also be regenerated. Then it went to the virs inserter where it sync and burst would be regenerated again.
NOW, all of this is ahead of a pre-corrector that was required to compensate for non-linearities in the modulation process of the transmitter. It had to look flat on the air.
AND don't forget the low pass filter. Video was band limited to 4.2 MHZ to avoid components bleeding over into the sound at 4.5 MHz.

.. If there is significant phase distortion of the chroma over the network, the phase of the incoming burst may also vary over its width, making it difficult to know where to set the phase of the re-inserted burst. The VIR reference had a much wider burst of chroma during the active line, which was supposed to fix this by ignoring edge distortions. .

Didn't know of this problem of burst phase distortion , nevertheless the burst must be the reference for regeneration I would think and not the higher level VIR chroma which may have phase shift wrt the burst?

To eliminate any guesswork, just have color bars on another vert interval line!

They DO run a line of color bars. But one of the biggest problems of NTSC is that it was compromised from the beginning. It had to fit in the same space as the existing B&W system.
As a result the bandwidth of the chrominance was limited. The I components were limited to 1.5 MHz and Q is limited to .5 Mhz. Not much detail in the color. AND its not even symmetrical. How screwey is that???
NOW, in Japan they had an analog HD system called the MUSE which I've heard took a 12 MHz channel. So when color (and HD) came along ,they should have allowed MORE bandwidth than what the old B&W system started out with.
SO, even today we are stuck with the constraints of an old system.

They DO run a line of color bars. .

I've seen them sometimes at top of underscanned picture.
So alternatively, this is as good as VIR insomuch as there should be no guesswork for the tech before adding new VIR before transmission, as all he has to do is line up the color bars in the vectorscope avoiding subjectivity.

And since, by 1975, NTSC still had 40 more years (counting cable), LSI chips could have been produced for consumer TVs to either derive reference from V.I. colorbars or VIR and making this the default mode of the receivers - keeping consumers' fingers away from contrast and tint - if not also saturation - knobs!

Cool early 80's GE projection with vir on ebay.

http://www.ebay.com/itm/Vintage-Antique-GE-40-Widescreen-TV-General-Electric-Back-Lit-40PW-3000K-/262643982022?hash=item3d26cd1ec6:g:PYsAAOSwHoFXu0K d

Cool early 80's GE projection with vir on ebay.



That set has 'VIR II' - wonder what improvements were made by then (1982)?

Magazine article on VIR
(https://books.google.com/books?id=CgEAAAAAMBAJ&pg=PA182&lpg=PA182&dq=POPULAR+SCIENCE+jUNE+1976&source=bl&ots=FS9DUdeoQQ&sig=0Hj-hj9X30dfuHj6XYl7pUad-4c&hl=en&sa=X&ved=0ahUKEwjar-_h6rnPAhUJ5CYKHcpEDjcQ6AEIJDAB#v=onepage&q=POPULAR%20SCIENCE%20jUNE%201976&f=false)

Had a Mot WARDS 19" with the VIR back in late 70s we paid $444 for brand new.. Great set till the fly shorted. Neighbor had a similar WARD set they tossed with a dead Vertical circuit. Swapped they Flys and it was up and runnin till i sold it years later and the vertical died 2 yrs after and it was tossed..

SR

Not sure what VIR2 is. Never heard of that.
Even before the HD switchover, stations were going digital in NTSC days.
I remember spots and syndicated programs coming in as a file from a digital satellite.
The files were fed directly to the playout server (a raid 5 computer). And then to air.
Sometimes the programs had low video or high chroma. Since it never went to analog at the station there was no way to adjust it.
This was eventually corrected as stations raised hell with the syndicators. Turns out the spots and programs had been uplinked by a secretary who had no knowledge of video parameters.

Had a Mot WARDS 19" with the VIR back in late 70s .. Great set...

SR

Did it make much difference when you ran it with VIR switched 'on'?

As I recall, the vir switch had its own set of controls. So, you could make it look like anything you wanted.
Those vir generators are all over Ebay if you wanted to play with one. Except for the VITS100, they also have a full field test generator with a boatload of test signals. The one I liked was the Tektronix 1910.
I've seen them as low as $30.
But I think the vits deleter and inserter section could be used in eradicating copyguard thats in the vertical interval.

As i recall, it did have internal color and tint adjustments for VIR, and manual adjustments for non Vir mode.. If i remember correctly, it performed well most of the time, but there were times when we had to disable it because it didnt agree with all programs...

SR

Here is the only 19" GE VIR set I've ever seen. I think most people bought the stripped down model despite the massive advertising campaign.

A friend of mine owns a VIR set with a gassy CRT.

I got a VIR-equipped Electrohome console from 1978 just yesterday. It starts but I'm sure it'll need work. Good thing I got the manual, and saw this thread, otherwise I still wouldn't know what it is.

I think I've solved the problem for RCA's original NTSC spec with a better implementation:
Just have colorburst for almost a whole line period in the last serrated segment of the field sync pulse
at ~50% luminance level(like GE-VIR) (picture level of light complexions.)

This gives nice clean, long duration subcarrier reference every sixtieth of a second (like VIR) (no burst every line needed)(who gives a flip about airplane-flutter.)

Then 1950s era receivers simply run separated vert sync thru a HPF to obtain subcarrier phase reference (no countdown circuit chips required 1970s VIR)

I think I've solved the problem for RCA's original NTSC spec with a better implementation:
Just have colorburst for almost a whole line period in the last serrated segment of the field sync pulse
at ~50% luminance level(like GE-VIR) (picture level of light complexions.)

This gives nice clean, long duration subcarrier reference every sixtieth of a second (like VIR) (no burst every line needed)(who gives a flip about airplane-flutter.)

Then 1950s era receivers simply run separated vert sync thru a HPF to obtain subcarrier phase reference (no countdown circuit chips required 1970s VIR)

Do you mean a different version of NTSC with subcarrier reference only in the vertical segment but not in each line?

1) Does not solve the problem of having it re-inserted in order to meet FCC signal specs. The original problem was in good part due to the locally reconstituted sync and burst having the wrong phase and amplitude compared to what had happened to the chroma coming over the network. Simply passing the degraded burst to the transmitter was a non-starter, as it could cause problems with color killers in receivers.
2) Not possible to use it with affordable crystal oscillator / phase-locked loop technology, since the oscillator in the receiver would need to have a free-running frequency within 30 Hz of correct, or side-lock could occur. With burst on every line, the free running crystal needs only to be within half that, or 7867 Hz. To insure quick lockup, the oscillator actually should be off no more that 10% or so of the nearest sideband and the loop bandwidth should be just wide enough to pass a beat frequency. Remember, horizontal rate sidelock is what was used in gated-rainbow color bar generators. This proposal would allow accidental vertical sidelock, and would require a crystal oven for stability and/or a customer color lock control to prevent it.

A very thorough theoretical study was done of the color burst to verify that once per horizontal was the right way.
http://ieeexplore.ieee.org/document/4051510/

"Not possible to use it with affordable crystal oscillator"

What if, after transition of H sync to black, the back porch was raised to 50%?

Seems the GE VIR locked nicely to 60hz interval reference with a cheap osc.
I must look up a schematic of a VIR board, haven't searched yet.

As for that paper from IEEE, they want $33 to read it, good luck with that.

The oscillator in the VIR sets locked to the regular burst as usual. The VIR made a secondary adjustment of phase. The goal of the VIR was to provide a secondary signal that suffered all the phase and amplitude perturbations as the video chrominance, all the way from the original encoding at the studio. VIR and the burst would always have the same frequency, since the local proc amp sync and burst reinsertion was locked to the incoming signal from the network. VIR was never intended to be a frequency reference.

Later, when the use of frame synchronizers became common, even the local frequency could be different from the incoming. VIR could no longer be carried all the way through the chain.
[Edit - maybe it could be - have to think about that]

For another thing, some stations began using local VIR insertion to adjust transmitters in an automatic closed-loop system, and this broke the chain as well.

Before frame synchronizers, the major networks had established atomic clock references to which everything was synced. These were so stable that you could sync a receiver to one network it displayed the picture from another (which I actually did for an experiment when I worked at Zenith). The National Bureau of Standards published a paper on using the network color burst as a better frequency reference than WWV.

As far as putting the burst on a pedestal:
1) The reason for the pedestal in VIR is so that any differential phase incurred along the chain would be compensated precisely nearer to skin tone luminance.
2) The reason for not putting the burst on a pedestal in the original NTSC/FCC specs was to prevent making it visible during retrace in sets that didn't have power retrace blanking. There was a proposal to put it on a pedestal to avoid possibly clipping it in studio amplifiers or transmitters, but this was rejected. Adding the pedestal after the standard was established would have required expensive surveying of the existing receiver population to make sure retrace was no longer a problem.

Mr WB, given the alleged advantages of PAL, (as well as its technical drawbacks)(and inconvenience of broadcast & consumer media playback incompatibility), do you think it was wise for those few South American countries to adopt (525/60) PAL-M & PAL-N?

Brazil certainly decided to play "odd man out" with PAL M. I can't see any real reason why they shouldn't have used NTSC. They were the only 525/60 country that didn't use NTSC.

PAL N is another matter. Argentina had the unfortunate combination of 625/50 monochrome TV with US channel spacing. So they couldn't use standard NTSC or standard PAL. Something had to give and the result was that ugly kludge of PAL N.

The arguments for PAL vs NTSC have been gone over many times. When Europe was looking at colour systems they could have adopted NTSC, suitably adapted to 625/50. The BBC and others experimented with 625 line NTSC (and 405 line NTSC) in the 1950s. Rightly or wrongly, at the time, the colour phase accuracy problems in NTSC were seen as severe. Hence both PAL and SECAM. In the later days of NTSC improved technology meant that NTSC could overcome the phase and differential phase problems.

Later still it was found that PAL was harder than NTSC to accurately convert to colour components for the digital world. Again advances in technology have made this unimportant.

Mr WB, given the alleged advantages of PAL, (as well as its technical drawbacks)(and inconvenience of broadcast & consumer media playback incompatibility), do you think it was wise for those few South American countries to adopt (525/60) PAL-M & PAL-N?

I think the main disadvantages of adopting PAL in South America were economical, that it made it less likely that a color TV manufacturing plant could be established there without government support either directly to the manufacturer or by high tariffs on imports. Plus, the production and stocking of special models for those countries may have raised retail prices.

Technically, once equipment became transistorized and stable, the only advantage of PAL transmission I can think of was the reduction of wrong hues in ghost images.

There may have been an improvement in color accuracy (as there was in Europe) if the cameras were matrixed to the EBU phosphor standards and receivers used unmodified R-Y and B-Y axes. In the US, color matrixing was a sort of wild west situation in which CRTs did not use NTSC phosphors, but cameras (at least the early ones) were designed for them, while different TV makers did various non-ideal modifications to the chroma decoders to compensate approximately.

As a side note, I met someone from Argentina who said that many there learned to understand Portuguese because Brazil had the best soap operas.

A late friend of mine who'd lived & worked in the TV/radio trade in Argentina sang the praises of system PAL N. He said if you put an average British PAL I & an Average Argentine PAL N set side by side you wouldn't be able tell the difference between them. He said Britain chose the wrong 625 system & should have gone for system N.

Must admit I was impressed with the NTSC M pictures I saw when I was in USA & Bahamas..

Some SA countries appeared to have been spooked by Euro trade delegations - they paid a hell of a price. Not as easy to bamboozle: Korea, Taiwan..

The concept of colour phase alternation, the basis of PAL, was considered by (I think) Hazeltine labs in the very early 1950s. While NTSC was being developed. Until there was a practical 1 line delay available at low cost the advantages of CPA were minimal. Both SECAM and PAL depended on having a 1 line delay in the receiver. Less critical for SECAM than PAL. Simple PAL receivers (without a delay line) were feasible but were hardly, if at all, marketed. The results were not good.

As for PAL N, I worked for MIchael Cox Electronics in the early 1980s when Argentina went to PAL N. We designed and supplied PAL B to PAL N transcoders as all production was done with standard PAL B kit. ISTR the pictures, as viewed side by side in the lab, weren't bad. On critical material you could tell the difference. Of course VHS and Betamax recorders reduced picture quality to below PAL N.

Do you think Argentina, Brazil, being what they are, might have been open to a discreet bribe or two... thus leading to those bastardized systems?

How did the UK deal with US videotapes 1967 - 1980? Did they get 16mm kinephoto copies? How good were analogue NTSC -> PAL tape conversions (using glass delay-lines to repeat/insert extra lines?) Did Cox make a box for this?

I remember watching the Andy Williams show on BBC1 (405 lines black & white) in the mid/late 1960's & the picture quality was dire = it looked blurred & any movement was jerky. Into the 70's the conversion quality improved but there was still the jerkiness & when in colour the colours were often wrong. The first live moon landing was converted twice = from 240 lines 10 frames per second to 525/60 FPS then to 405/50 FPS. The later landings looked very clear in comparison

Cox never made field rate converters.

The world's first electronic (as against optical) 525/60 <> 625/50 converter was the BBC's analogue machine using glass delays. From 1968. I believe it worked well but was a beast to keep working nicely. The IBA "DICE" was the first digital converter and worked very well. 1971 I think. Followed by the BBC's ACE with 4 field, 4 line interpolation. This set a pretty high bar for quality until motion compensation was feasible.

Most 2" quadruplex machines were multistandard so could reply NTSC tapes in Europe. A lot of US programmes back then were produced on film which was just run 4% fast in 50Hz countries. A rather happier solution than 3:2 pulldown.

Argentina were stuck between a rock and a hard place. US channel spacing and 625/50 meant wahever they used would be unique unless they opted for a wholesale change to 525/60 and NTSC. In retrospect this might have been feasible as just about any 625/50 monochrome set will display 525/60 with minimal adjustment.

We had a 19" GE set with VIR that we got shortly after it was introduced. Ours was a 1977 model. It never worked right. Saturation and hue would just randomly jump all over the place. I have never seen faces such a brilliant shade of bright blue as on that set. It seemed to vary from one station to another, and I was convinced that our local ABC affiliate wasn't actually transmitting the signal but had some kind of noise present that tricked the TV into switching into VIR mode. Anyway we turned it off after a while.

About the same time the shop I worked in was selling Quasar TVs and in around 1979 or 1980 they came out with Super Dynacolor that also had VIR. I believe those and the GEs were the first on the market.

The second set of controls for VIR only meant that there were two ways for the consumer to monkey with the color setting and make everything terrible with or without VIR. The awful truth of VIR to the consumer is that only GE sets seemed to support it, and GE had a reputation for lousy quality and iffy reliability.

There were three GE color 19" sets in the extended family (one a JCPenney rebadge) and each one had a CRT that went bad quickly with weak green and smeared reds. The one my mother had came with a hair-trigger color-killer that no number of shop trips could correct. I think they gave up after the 8th repair visit. The tube went south and lost correct color along with focus within 5 years from new even with minimal hours (due to that color-killer annoyance).

A friend owns the only GE VIR set I've seen in person. That set has a gassy CRT.... it arcs between CRT elements then goes into shutdown.

The concept of colour phase alternation, the basis of PAL, was considered by (I think) Hazeltine labs in the very early 1950s. While NTSC was being developed. Until there was a practical 1 line delay available at low cost the advantages of CPA were minimal. Both SECAM and PAL depended on having a 1 line delay in the receiver. Less critical for SECAM than PAL. Simple PAL receivers (without a delay line) were feasible but were hardly, if at all, marketed. The results were not good.


"Less critical for SECAM than PAL" caught my attention here.

I had always thought that the delay line was strongly encouraged in PAL for the color correction benefit, with some manufacturers leaving it out to save a few Marks (resulting in "Hanover bars", and called "Simple PAL") and others using a delay line to store alternate R-Y lines and escape patent royalties payment, wheras in SECAM a delay line would be absolutely essential as SECAM only transmitted one axis of chromience with each line.

9OooIDo you think Argentina, Brazil, being what they are, might have been open to a discreet bribe or two... thus leading to those bastardized systems?


Well, there are other reasons to consider before one comes to the conclusion that a few billion Cruzandos changed under the table.

Brazil used and still uses 60Hz utility power, so they logically used the 525-line, 60-field USA system. Like all of the Americas*, channels had/have 6MHz total bandwidth each, hence SECAM or PAL B, D, G or K were off the table. Brazil went color far later than the USA did. Whether their decision was done to reject American dominance or simply to throw away that pesky hue knob may never be known.

Argentina and Uruguay were another matter. The had/have 50Hz power. They used System N, with 625 lines at 50 fields (25 frames) per second. Like Brazil, they only started using color when the PAL system was well established, and no country ever made a standard of NTSC and 50 fields, so PAL must have seemed a logical choice.

*Excluding some Caribbean Islands that used 50-field systems from their parent countries, all either low power or cable only.
Mexico experimented with System N monochrome. A TV DXer showed me a photo of an ID slide from XEFB-TV (then channel 3), Monterrey NL. Below the call sign, it said: "Nuestra siguiente programa se ve mejor en un Phillips". This DXer told me he lost vertical hold the instant the slide was replaced by the program.

System M and system N had very closely matched matched line rates (15750 versus 15625), thus horizontal sync was no problem. It is also true that one system's vertical rate may be compensated to the other with adjustment of the vertical hold, size and linearity controls. However, having the field rate match the power supply frequency is still desirable.
I own an ATSC converter box that offers PAL B/G video output (along with 480i, 480p, 720p and 1080i).
When I fed its PAL output to my 1958 Emerson TV, the picture was sharper but with more flicker, as I expected. However, the picture wobbled in a cycle- the picture looked like an image atop a shaking bowl of jelly. My suspicion is that a 60Hz magnetic field from within my home (possibly the autotransformer power supply of the television itself) was interacting with the 50Hz field of the vertical yoke.

Well, there are other reasons to consider before one comes to the conclusion that a few billion Cruzanandos changed under the table.

Brazil used and still uses 60Hz utility power, so they logically used the 525-line, 60-field USA system. Like all of the Americas*, channels had/have 6MHz total bandwidth each, hence SECAM or PAL B, D, G or K were off the table. Brazil went color far later than the USA did. Whether their decision was done to reject American dominance or simply to throw away that pesky hue knob may never be known.

Argentina and Uruguay were another matter. The had/have 50

There is probably some elderly engineer there or some obscure tech publication where that info exists.

"Less critical for SECAM than PAL" caught my attention here.

I had always thought that the delay line was strongly encouraged in PAL for the color correction benefit, with some manufacturers leaving it out to save a few Marks (resulting in "Hanover bars", and called "Simple PAL") and others using a delay line to store alternate R-Y lines and escape patent royalties payment, wheras in SECAM a delay line would be absolutely essential as SECAM only transmitted one axis of chromience with each line.

My understanding: In PAL, the length of the delay determines if the chroma is exactly phased right from line to line. In an NTSC comb filter, the exact length of the delay determines if the chroma and luma sidebands are precisely separated. In SECAM, the delay is only providing low-resolution FM chroma, so doesn't need to be so precise.

What was the Japanese experience with their mix of 50Hz and 60Hz power?

In PAL the delay line length is very critical, to within a few degrees of subcarrier. A good NTSC comb filter is likewise critical to get good subcarrier cancellation. A SECAM delay line is relatively uncritical.

Many import Japanese tube era TVs I've seen seem to have on average more and bigger lytic caps than American sets so I'd imagine they had issues and dealt with it by liberal use of capacitive filtering.

A-ha! I see why I was confused.

In PAL, the quality (more specifically, the precision) of the delay line is critical, but the delay line can be left out if one were tolerant of "Hanover bars".

In SECAM, the mere presence of the delay line is critical (no delay line, no SECAM).

Discovered Good article on VIR in RADIO-TELEVISION. It states VIR was designed for pro application, and only later was it extended to consumers (much the same way as DTMF routing was used behind the scenes by telcos, and only later extended to consumers.)

The article describes the use of the Tektronix 1440, a very precision instrument with no tweaking controls on front panel (unlike the consumer VIR) and how the 1440 (in a closed loop) would correct a transmitter for instance.

By providing subjective fine tuning on the home TV version, they were either admitting that they had lost the control VIR promised, or that the built-to-a-price GE circuit board lacked the precision of the pro 1440.

Wooo digging up an old thread!

Anyway - I've always wondered - how does the PAL decoder know which way the phase is, to decode properly?

"Oscillating burst"

A (R-Y) or -(R-Y) component is added to the burst on alternate lines, making its phase plus or minus 45 degrees from the NTSC burst.

As mentioned somewhere here, there was a patent on detecting this in the receiver, but one maker avoided the patent by not using the detector. Instead, they added a button so the user could flip the phase sequence from plus/minus to minus/plus in case it came up wrong at random.

VIR= Vertical Interval Reference. Remember, TV stations using video had to stay synchronized to the network color burst reference for timing and interchange purposes. Also remember there was Time Code involved for locally produced video content using video tape sources. Known as SMPTE (Society Of Motion Picture and Television Engineers) Time Code. Hope this explains the underlying issues with VIR's use and implementation and allow set owners freedom of their vision and taste in color settings at home.

The thread that refuses to die!

Kent's comment just made something click for me: on our GE VIR set, everything always went whacky when the local ABC affiliate switched from network content to local, either programming or commercial breaks: tint so far off you couldn't manually adjust it so bad. It was common to see bright blue faces for a few seconds when they switched. It must have been a sync error at the station.