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Old 07-08-2018, 05:44 PM
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GE 1-tube color camera February 1954

A bit higher-quality scan of the press photo for the GE camera built for operation with the CBS chromacoder.

See a grainier copy and other related photos and text at:
http://www.earlytelevision.org/chromacoder.html
Attached Files
File Type: pdf GE 1-tube color cam Feb54.pdf (249.9 KB, 63 views)
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Old 07-19-2018, 02:44 PM
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Why the didn't continued the project?
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Old 07-19-2018, 05:06 PM
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Quote:
Originally Posted by Telecolor 3007 View Post
Why the didn't continued the project?
The GE chromacoder was a jury-rigged system to convert CBS field sequential to RCA NTSC after we switched from CBS to RCA color encoding formats. Once that switch occurred CBS system users briefly used the chromacoder to get use out of their very expensive CBS cameras till those cameras broke down.

The chromacoder had sub-NTSC picture quality so as soon as stations could afford and justify replacing CBS color cameras/chromacoders with proper NTSC cameras they did.
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Old 07-19-2018, 05:21 PM
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Quote:
Originally Posted by Telecolor 3007 View Post
Why the didn't continued the project?
Probably multiple reasons:
CBS reluctance to support the RCA-based NTSC color system.
In practical application, the field sequential cameras had no sensitivity advantage over the three-tube cameras.
The single-tube camera advantage of perfect registration was lost when the signal was converted to simultaneous RGB through the use of three tubes in the Chromacoder converter.
The field sequential camera was prone to primary signal leak from one color to the next due to camera tube lag. Fixing the hue shift would be difficult and complex.
Color fringing on motion (probably not awful, but noticeable in comparison to a simultaneous 3-tube camera).
Only NBC/RCA was pushing local stations to convert to color, so of course those stations bought RCA equipment - little market for the CBS Chromacoder compared to RCA equipment. RCA supplied all types of TV gear, and all the training and support anyone needed. CBS was just not a broadcast equipment supplier of the required magnitude. If anyone had contracted CBS (or a subcontractor like GE) to build the Chromacoder system, they still would have to contract with RCA and/or others to put together a complete station. RCA was a one-stop shop that the broadcaster could have confidence in.
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Old 07-20-2018, 12:33 AM
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The concept appeared again for the Apollo moon landings. To save weight the colour camera on Apollo 12 and subsequent missions was single tube with a colour wheel. Apollo 11 had a monochrome camera.

Looking at this article it seems my memory was only partially correct:
https://en.wikipedia.org/wiki/Apollo_TV_camera

A12 was the first mission to bring a colour camera to the lunar surface. A10 onwards carried a colour camera.

Back in the late 1960s/early 1970s electronic framestores didn't exist so conversion to NTSC was almost as hard as it was for the chromacoder.

Again I've realised that my memory is faulty. Framestores did exist by then. The 2 examples I know of are the BBC's analogue PAL<>NTSC converter from 1968 and the IBA's DICE converter where development started in 1971. The former used quartz delay lines, the latter used early DRAM.
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Old 07-20-2018, 10:52 AM
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The situation with stations needing end-to-end help with new technology has not changed over the years. The station chief engineers need broad knowledge of how to connect things and keep them running, and do not have the time to delve deeply into any one piece of technology. In the case of digital TV, for example, help was needed from video encoder makers to choose the bit rates for the multiple program streams. In ATSC 3, where there is a huge array of choices for error coding and robustness, they will need similar help. Of course, with the demise of RCA, help must come from individual manufacturers of the particular hardware that a station uses. The industry has managed this problem by sponsoring "plugfests" as part of the standards-writing process, where multiple manufacturers mix and match their gear into end-to-end systems to debug any interface issues.
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