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Philips X25K121 first European colour TV set.

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Nuvistor
(@nuvistor)
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I understand the sampling of line 19 and how that can be achieved, it’s the statement about the mathematical formulae that proved  the references in the VIR compared with the output of the R-Y and B-Y. 
It’s measuring amplitude not phase, too much for my old brain to get my head around but it obviously worked. It wouldn’t have easily been achievable before IC’s became available.

I wonder if the maths was known when the system was devised but impractical to implement, or did some mathematician have a light bulb moment in the early 70’s, hats to them if they did.

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Frank

 
Posted : 25/10/2019 11:06 am
Terrykc
(@terrykc)
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@nuvistor

I don't see the need for all that line 19 business, other than to signify that VIR was in use. The various signals derived from it already existed or could be calculated simply.

For example: the Chrominance Reference has the same phase and amplitude as the colour burst, the Luminance Reference can be derived from the 100% bar in the ITS pulse and bar signal and the timing pulses can be referred to the horizontal sync pulses.

I note that the mathematical proof that it works is not presented! Not that I think I would be interested in subjecting it to detailed analysis!

When all else fails, read the instructions

 
Posted : 25/10/2019 11:45 am
Nuvistor
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Posted by: @terrykc

@nuvistor

Not that I think I would be interested in subjecting it to detailed analysis!

I couldn’t ☹️ .

Frank

 
Posted : 25/10/2019 11:59 am
Nuvistor
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The Electronic Servicing magazine referenced in an earlier post has a few articles in various copies of the magazine through the 1970’s about VIR .

This is a different take on Color correction from RCA, ColorTrak.
americanradiohistory.com/ARCHIVE-RCA/RCA-Engineer/1976-06-07.pdf

Frank

 
Posted : 25/10/2019 2:22 pm
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