[opendtv] CBS color wheel and other nostalgia

Jonas wrote:
>
> Cliff Benham wrote:
>> Like today's incompatible DTV systems which are not only technical
>> battles, but very much political ones as well, the CBS color vs.
>> RCA battle was full of political intrigue and underhanded business
>> dealings as well.
>>
>> For an interesting read about what was happening way under the
>> color radar, read this:
>> http://www.earlytelevision.org/color_tv_cooper.html
>
> Thank you,  Cliff.
>
> In fact,  "earlytelevision" is a very,  very nice site.
>
> I would like to invite you to visit two CBS system enthusiast
> sites:
> http://www.sptv.demon.co.uk/cbscolor/
>
>
http://home.att.net/~pldexnis/potpourri1/1951CBScolor2004/1951CBScolor20
04.html

Very fascinating stuff.

IMO, the closest technical comparison between the CBS scheme vs what
eventually became NTSC color, back in the 1940s, is what happened in
1991 when the FCC decreed that HDTV would have to fit in the 6 MHz
channel. In both cases, the FCC pushed to have the improved TV system
operate within the same channel constraints as had been established
already. (Of course, the NTSC color system was compatible with B&W
receivers, whereas the the DTV signal is not compatible with analog
receivers.) In both cases, even if the initial results of the FCC
decision might not have been spectacular, eventually the decision proved
to be a good one, as technology caught up. In both cases, the RF
distribution channels first proposed for the new service (UHF in the
former, DBS in the latter) were in fact adopted eventually, but not for
that specific purpose.

The CBS system seems somewhat like a 4:4:4 color system. Ditto the
original kludgy RCA system. They had to attempt to conserve on bandwidth
somehow, since equal bandwidth was allocated to each primary, but that
came at a high price. Like, low resolution and flicker, and still the
bandwidth required was far greater than the existing standard. Cliff's
URL shows how CBS tweaked it down from 16 MHz to 12 MHz channels, but
ultimately the fix was to call for moving color TV to the UHF spectrum
in order to have access to wider channels. Instead what happened was
that TV did move to UHF, but not for wider channels. Just for more TV
channels.

Seems like the FCC decisions back then were on target. It seems that for
some reason, the kludginess of all the color systems of the 1940s did
not strike their inventors that way. *Very* much like analog HDTV
techniques, I think. And also interesting is that the FCC was correctly
intrigued by UHF, without tying UHF to just color TV.

Anyway, all very fascinating. Would have been fun if OpenDTV had existed
back then. For the record, I was unimpressed with HDTV concepts in 1986,
when what was being discussed was a DBS scheme with only 6 channels for
this new service, to remain separate from "regular TV." I'd like to
think I'd have been equally unimpressed in the 1940s, with the idea of
UHF being used just for wide-band color TV.

But Jonas, these 1940s battles were broader in scope than the current
battles between DTT systems. In today's case, the only objects of debate
are physical layer differences. In each case, MPEG compression and MPEG
transport is used. To me, they are more similar than different.

Bert
 
 
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