Happy Birthday 1953NTSC Color :)
 

Tried to interest the local Big Rapids newspaper in this bit of December 17, 1953 TV history, but to no avail :boring:

Sixty years ago today, television burst into color.

It was a long time coming, mid-1941 to late 1953, and long to be accepted by the black-and-white-TV-enamoured '50s public.

But the Big Rapids Pioneer didn't buy it. :no:

This 'n That

As for behind-the-scenes developers of analog color television, these are some of the companies who contributed to the 1953 NTSC color television standard:

• American Telephone and Telegraph Corporation
• Farnsworth Television and Radio Corporation
• General Electric Company
• Hazeltine Research, Inc.
• N. V. Phillips' Gloeilanpamfabricken
• Philco Corporation
• Westinghouse Electric Corporation

It's a list that was compiled by RCA and appears on a label inside the cabinet of every CT-100 made.

In honor of the occasion, I have benched my CT-100 (see pix) and am giving her an electronic massage of sorts: fix a drifting brightness control (poor C7 ground), recalibrate the hue control, and so on...

I'll also investigate another CTC2 modification (the set had a composite input added in 2007 that was based upon a 1956 RCA circuit.) I hope now to add an S-video input based upon WA2WISE's concept presented here on AudioKarma a number of months ago. If successful, it should completely rid the 15GP22 image of all 'sparkling' around fine print and other such cross-color. Thanks to Cliff Benham who has loaned me a composite interface adapter for the project.

Full circle. Also, things keep moving forward and the future of TV is already here, due in no small part to one of our own members here at AudioKarma. A short quote if I may: "Working together with a team of Zenith research engineers, Wayne Bretl, Richard Citta, and Wayne Luplow created the digital high-definition technology now mandated by the FCC to replace the nation's ... old analog system." Not to worry, we'll all be keeping the old one alive ;)

Pete

My only regret is never working for a company with a cool name like "Gloeilampenfabrieken"

I also want to say that S-video seems a bit like like cheating. The NTSC system was selected with all its warts in full view.

30 years ago I did a lot of research to reduce those warts... :D

And I was a few months old when NTSC color was born. :D

Actually that company is Philips. They were known as Norelco in the US. Gloeilampenfabrieken literally means "light bulb manufacturer" in Dutch. It is just the ending of the company name. Similar to the "Motor Company" part of Ford Motor Company.

Apparently they started specific and then broadened out, 5 years before that name they were known as Metaalgloeilampfabriek (Metal filament lamp factory) :D

Probably a good thing they didn't keep that naming scheme or you'd have a mass of companies with names that are incredibly confusing to the non-speaker... Philips bandrecorderfabriek, philips keukenapparatuurfabriek etc ;)

Pete,

In honor of NTSC color tv's 60th birthday, this article from the Jan. '54 Radio Age.

Thanks for that, Steve! It looks like the article continues further - do you have the rest?

Sorry about that. Just added the final page of the article to my post.

-Steve D.

Thank you for posting the article, Steve.

I wasn't able to get a decent display of Steve's attachments.

My question is... what exactly did Phillips contribute to NTSC? I know they (via Maggotbox) were able to later contribute ghost canceling...

Philips (note one "l") is not listed in the committee member affiliations of the NTSC.

That list was lifted from my website and was generated years ago. Today I checked the label in the CT-100 and it mentions patents. So, perhaps Philips held a patent from b&w set days that got funneled into RCA color circuitry?

Pete

I think this is the patent in question: https://www.google.com/patents/US283...ed=0CEEQ6AEwAg

Apparently Philips claimed invention of the idea of combining the color and luminance signals together.

Much too late to be a patent on basic combination of luminance and color subcarrier. What it is, is a proposal to put one color difference signal on the lower sideband of a high-frequency subcarrier, and the other color difference signal on the upper sideband of a mid-frequency subcarrier, with the two sidebands overlapping but interleaved, similar to the way NTSC chroma and luma are interleaved.

Here's a clear scan of the patent:
http://pdfpiw.uspto.gov/.piw?Docid=0...iew+first+page

Philips claims priority, with application in the Netherlands on May 1, 1952 and US patent applied for April 28, 1953 and this patent took 5 years to be approved in the US.

I suspect that there originally more claims and this potential interference patent could be the reason that RCA dropped their obviously superior I & Q system like a hot potato!

Jas.

Interesting that this might be construed to have priority - it put the color difference signals on different subcarriers instead of a common subcarrier. However, it did use unequal sidebands, and that might be the interference.

More speculation...

It's true that altering the CT-100's CTC2 chassis I/Q demodulation to R-Y/Q demodulation in the CTC2B chassis "saved one resistor in the matrix," as a retired RCA exec retorted on the internet some years ago.

It was then soon speculated that patent infringement had a hand in the switch.

Certainly the latter is the finer argument, as the quadrature transformer in the CTC2 chassis was replaced with another part number in the CTC2B. The reason: I/Q demodulation is in quadrature and R-Y/Q demodulation is not. Hence the need to go to the added expense of replacing a true quadrature transformer with one that isn't.

The really interesting question becomes: is there really any significant cross-color resuling from demodulation in the 21-CT-55 versus the CTC2?

I suspect very little.

Pete

Actually, moving the I axis to R-Y would produce no crosstalk. The Q signal is narrow band, and the I signal has both low frequency sidebands (double) and high frequency (lower sideband only).

Since the wideband R-Y demodulator is properly matrixed to form the R signal when combined with the Y signal, it gets the correct proportions of I and Q low frequencies (in the double sideband region below +/- 500 kHz).

What does the R-Y demodulator get in the high-frequency I region? Because it is not exactly in phase with the I signal, it gets mostly the correct I high frequencies; but it also gets a small proportion of the Hilbert transform of the I high frequencies (that is, I high frequencies with a 90 degree phase shift). The result is that the R-Y shows some distortion of high frequency transients that would be perfect in a true I demodulator.

sin (33) = .545 (pretty large) - multiplier for the undesired Hilbert component.
cos (33) = .839 - multiplier for the desired I signal, which also is the correct multiplier for the I component of R-Y.

Wikipedia has an illustration of a square wave and its Hilbert transform:

http://en.wikipedia.org/wiki/Hilbert_transform

If the original I signal is a square wave of frequency greater than 500 kHz , what comes out of the R-Y demodulator is a sum of the square wave and a smaller proportion of the shown Hilbert transform. So, rising edges get pushed towards cyan, and falling edges get pushed towards red.

Whether this is noticeable or not will depend on the subject matter and also on whether the viewer knows what to expect. In most cases, these kinds of distortions do not become strongly apparent unless you have a correct picture to compare to. There might be exceptions for things like colored title letters, which the viewer may assume to originally have uniform color on the left and right edges.

Here is an article by James O'Neal that appeared in TVTechnology, and now appears to be posted in the clear, with a nice shot of RCA field engineers working on a prototype:

http://www.tvtechnology.com/article/...versary/222948

The question is really whether the shifting of one demodulation axis was actually noticeable in the reproduced picture. I suspect that in the lab, and with the pressure to reduce the cost of the receiver, trimming the demodulation circuitry was an important option.

When the CTC2B chassis was offered, it was already nearing obsolescence with the simplified CTC4 already underway. The other distortions in the production and delivery chain in 1955 surely must have offset any noticeable distortion in the displayed picture color transitions.

The original I/Q quadrature modulation scheme was only a means to try and maintain some sort of a minimum chrominance bandwidth which at the end of the day I imagine in practice was not really noticed when it was shaved off.