NTSC versus PAL
in [Repair]
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From: Sylvia Else on 7 Apr 2010 10:31 On 8/04/2010 12:21 AM, William Sommerwerck wrote: >>> Yes -- a lack of consistency. That was not the fault >>> of NTSC, but of the broadcasters. > >> I have to wonder what the broadcasters were doing to achieve >> that. Contriving to get the colour burst phase consistent amongst >> cameras in a studio (so that the tint stayed the same for a show), >> but inconsistent with the actual colour subcarrier, would take >> some doing. > > There is no subcarrier or burst signal in the cameras. They aren't needed at > that point, and are added during the encoding process. Ok, so the separate colour signals (and luminance?) are sent from the cameras. Still, at some point the colour signals have to be encoded using the colour subcarrier, and a bit of the latter has to be included as the burst. Failing to keep them in phase would require a considerable amount of indifference. Which I think you've also said ;) > > Setting them up is another matter. The early episodes of "Barney Miller" > provide a good example of poor setup, with inconsistent color, and poor > convergence. > Poor convergence? The mind boggles. Sylvia.
From: Michael A. Terrell on 7 Apr 2010 10:50 William Sommerwerck wrote: > > > Part of the difficulity in understanding is that perhaps you > > don't have experience with early American color televisions... > > I certainly remember how in the 60s we had to adjust the tint > > control on a regular (show by show) basis, because of lack > > of consistancy. > > Yes -- a lack of consistency. That was not the fault of NTSC, but of the > broadcasters. And AT&T who provided the coaxial cables that fed the video to all the stations on a network. The tint and chroma level could be adjusted at every facility in the system. I knew someone who worked for AT&T at the time, and he told me what a pain it was to compensate for the cable. When the network switched to a different studio or city for a show, it threw everything out of calibration. > > Anyone who had one of those old, tube (valve) color sets, > > with the 21" round color CRT, will remember seeing green > > skies, and blue grass while having skin colors set to the > > proper shade. Get the sky blue, and the skin turned red, > > or blue, or green! > > I don't think that's correct. The cameras (and/or encoders) would have had > to have been very badly set up for that to happen. > > On a related subject... I remember reading long, long ago that the first RCA > color TV had /four/ controls for adjusting the color, which the author > described as a "combination lock"! Anyone know anything about this? He may be talking about the three 'drive' controls that set the gain for each channel. These are set up to provide equal gain to get a white line during setup. They are service adjustments on TVs, but on an early design they may have been easier to get to. Some TVs still had hollow plastic shaft extenders that passed through the rear of floor model cabinets to adjust these and other pots. The fourth would be the actual dolor intensity control. -- Lead free solder is Belgium's version of 'Hold my beer and watch this!'
From: William Sommerwerck on 7 Apr 2010 11:16 >> Setting them up is another matter. The early episodes of >> "Barney Miller" provide a good example of poor setup, with >> inconsistent color, and poor convergence. > Poor convergence? The mind boggles. Oh, yes. The pickups had to be aligned. The "modern" system, in which solid-state sensors are attached to a prism/beamsplitter was not practical with vidicons and Plumbicons.
From: William Sommerwerck on 7 Apr 2010 11:20 >> On a related subject... I remember reading long, long ago >> that the first RCA color TV had /four/ controls for adjusting >> the color, which the author described as a "combination lock"! >> Anyone know anything about this? > He may be talking about the three 'drive' controls that set the > gain for each channel. These are set up to provide equal gain > to get a white line during setup. They are service adjustments > on TVs, but on an early design they may have been easier to get to. No, these were supposedly user controls. Anybody got a photo of the user controls for a CT-100?
From: Dave Plowman (News) on 7 Apr 2010 12:03
In article <hpi4c4$tk4$1(a)news.eternal-september.org>, William Sommerwerck <grizzledgeezer(a)comcast.net> wrote: > There is no subcarrier or burst signal in the cameras. They aren't > needed at that point, and are added during the encoding process. > Setting them up is another matter. The early episodes of "Barney Miller" > provide a good example of poor setup, with inconsistent color, and poor > convergence. So camera setup was poor - as was the later stages of transmission? This certainly wasn't the case in the UK - despite the transmitters being fed with land lines. -- *Where do forest rangers go to "get away from it all?" Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound. |