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Forum 135

Philips X25K121 first European colour TV set.

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Colour Television

Last Post by Nuvistor 5 years ago

24 Posts

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Nuvistor

(@nuvistor)

Posts: 4633

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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.

Frank

Posted : 25/10/2019 11:06 am

Terrykc

(@terrykc)

Posts: 4004

Member Rest in Peace

@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

(@nuvistor)

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