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  #31  
Old 06-26-2011, 06:16 AM
JBL_1 JBL_1 is offline
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Quote:
Originally Posted by MelodyMaster View Post
I would disagree, IQ demodulation gives a depth of yellows and oranges and subtle shading of flesh tones that just don't seem to exist in bandwidth-restricted RY demodulation.
It is a linear system and you can make the same hues with either system. The design goals were different and that it why the look different. The bandwidth doesn't affect the hue. A 90 degree (R-Y)/(B-Y) system produces the same hues as a 90 degree I/Q system.
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  #32  
Old 06-26-2011, 10:24 AM
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Agreed

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Originally Posted by melodymaster View Post
i would disagree, iq demodulation gives a depth of yellows and oranges and subtle shading of flesh tones that just don't seem to exist in bandwidth-restricted ry demodulation. Case in point, i have a late-sixties ikegami and mid 70s conrac 19" rack monitor, both with conrac broadcast tubes, both used as studio check monitors, both aligned to test instruments... The ikegami uses iq, and has a subtlety to the hues that the conrac can't approach. Even my admiral c322c1 with sulfide 21azp22 doesn't have the rich reds of the ikegami. (it uses ry) i have never seen any tv using simple quadrature that approaches he colour fidelity of a set using dual bandpass demodulation. This is one area where pal definitely is at a disadvantage, since it doesn't have a 1.5 mhz modulation channel.

The irony, now that analog tv is on its way out, is that ry demod was used because it's easier and cheaper in the analog domain, and one could "play around" with the angles to "improve" flesh tones to compensate for picture tube colorimetry; you can't "play around" with iq demod. But now digital methods make iq demod easy, and a digital matrix can make any required adjustmant to vectors.

Part of the fascination of early colour sets is that the design did everything the hard way.
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  #33  
Old 06-26-2011, 12:08 PM
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MelodyMaster MelodyMaster is offline
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Quote:
Originally Posted by JBL_1 View Post
It is a linear system and you can make the same hues with either system. The design goals were different and that it why the look different. The bandwidth doesn't affect the hue. A 90 degree (R-Y)/(B-Y) system produces the same hues as a 90 degree I/Q system.
The hues are the same, but the 1.3 Mhz "I" bandpass for orange-cyan, to repeat myself, allows for greater subtlety, there is more resolution in the colours to which our eyes are most sensitive. Freckles and lighting reflections are more apparent. Also the design of dual bandpass demodulation allows for less crosstalk, meaning no blue ringing at red to green transitions eg. The colour "fits" the black and white image better.

And, subjectively, again, oranges and thus flesh tones just look richer, backgounds have more saturated colour, whether or not there is a technical basis for that observation. Actually, having accurately rendered green and cyan dark areas is something that very few sets get right, maybe due to chroma-luma gamma tracking, which again seems better with full bandpass demodulation. (and the "I" channel is orange and cyan..)

As for background colours, my Samsung plasma TV (PN50C8000) gets it right - as does the Ikegami, I tried a Sony LCD which was way off for background colours, as was my Sony XBR. (but the Sony HX800 was marginally more accurate on flesh tones, even after calibration of the Samsung) The Conrac is better than either Sony set but worse than the Ikegami.

Last edited by MelodyMaster; 06-26-2011 at 12:21 PM.
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  #34  
Old 06-26-2011, 09:45 PM
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Quote:
Originally Posted by JBL_1 View Post
I would think at this stage all the early color sets all used the same tubes and phosphors and classic chroma demodulator gain and phase.
Yes, no need for non-standard gains and angles since they all used the same phosphors.

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Originally Posted by JBL_1 View Post
The auto flesh circuits that operated on color difference signals were less obnoxious than those that pulled the color sub-carrier.
Here I disagree. The hue pulling circuit could affect hues around flesh tone without killing greens, cyans, and blues. Effectively, all the linear matrix type auto flesh tone circuits did was to decrease the Q axis gain, so you tended towards either reddish orange or cyan. Depending on how far the manufacturer went with it, you could end up with "the tan cowboy on the brown horse riding into the orange sunset" while trees and grass got desaturated and had a tendency to turn brownish. Engineers never used a set with that "one button auto color" engaged (well, maybe their family members did), preferring to adjust the color when necessary.

The thing about RCA's auto color that I didn't like was the setting of color level based on average chroma level. This resulted in the color level turning up or down based on scene content, and I often saw obvious failures when the scene cut to talent wearing bright red clothing. It did result in "calendar color" (somewhat oversaturated on low-saturation scenes), which the public seemed to like. I PO'd someone I interviewed with at RCA once when I told him this was not a good idea in my opinion.

The hue pulling circuit was invented by my colleague Ted Rzeszewski at Motorola. For some reason, Motorola never used it, but licensed it to RCA.
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  #35  
Old 06-27-2011, 04:19 PM
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Quote:
The hue pulling circuit was invented by my colleague Ted Rzeszewski at Motorola. For some reason, Motorola never used it, but licensed it to RCA.
Sounds like sabotage....

Tom C.
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  #36  
Old 06-27-2011, 09:50 PM
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Hoorah!

Can you say $8,800?
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Last edited by TubeType; 06-27-2011 at 09:52 PM. Reason: Spelling
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  #37  
Old 06-27-2011, 10:02 PM
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Wow...Eighty-eight hunnert dollars for a non-working, somewhat banged-up 1954 television...An' if I'd had NINE grand to throw around, it mighta been mine !!
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  #38  
Old 06-27-2011, 10:11 PM
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Holy Crap! And with a dud CRT, no less! Glad I got min when the getting was good....
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  #39  
Old 06-27-2011, 10:17 PM
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it is quite amazing....... but then more rare than a ct100 so that ='s more money.
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  #40  
Old 06-27-2011, 10:22 PM
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Wow, that's a darned expensive Fish Tank!
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  #41  
Old 06-28-2011, 07:44 AM
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I know where one of these is, in Ontario. Or at least where it was.
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  #42  
Old 06-28-2011, 11:41 AM
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It is still there, if you are talking about Area 31.
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  #43  
Old 06-28-2011, 12:05 PM
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Whatever became of Rob, anyways?
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  #44  
Old 06-28-2011, 12:09 PM
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Originally Posted by Kamakiri View Post
Whatever became of Rob, anyways?
I was wondering the same thing. I haven't heard from him for many years. I know he was having some health problems from a car accident so hopefully he is still doing good.

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  #45  
Old 06-28-2011, 12:45 PM
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He is still there. I swapped emails with him recently. He still has is TV collection and his ediphor projectors. His health is not good, but he is hanging in there.
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