Reclaiming some Digital TV Channels
K. B.
The DTV channels are extremely valuable, and broadcasters
have tried for several years to find ways to use them for
more than just high-definition TV signals -- for example, by
transmitting a version of their programs that's customized
for mobile devices, or leasing part of their channel to data
service providers.
~~~
Kirk Bayne
alt.video.digital-tv Home Page
<http://avdtv.tripod.com/avdtv.htm>
Sal M. Onella
> <http://latimesblogs.latimes.com/technology/2009/11/radio-and-tv-broad...>
>
> The DTV channels are extremely valuable, and broadcasters
> have tried for several years to find ways to use them for
> more than just high-definition TV signals -- for example, by
> transmitting a version of their programs that's customized
> for mobile devices, or leasing part of their channel to data
> service providers.
>
> ~~~
>
> Kirk Bayne
> alt.video.digital-tv Home Page
> <http://avdtv.tripod.com/avdtv.htm>
Interesting article about a good idea but the concept is ancient. FM
radio broadcasters provide "hidden" transmissions under FCC rules
called Subsidiary Communications Authority or just SCA. See <http://
www.fcc.gov/mb/audio/subcarriers.html>.
SCAs transmit background music ("Muzak"), data (news and traffic),
pictures (photo-fax for newspapers), Reading for the Blind or
alternate language programming. Some of these have been around for
many decades. It works in both the analog and digital domains. In
analog it's usually termed Frequency Division Multiplexing; in the
digital domain, it's commonly called Time Division Multiplexing.
TV stations also provide alternate language programming, data,
messages and closed captions.
Sal
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Of course unemployment is still rising. The government is attacking
business in an unprecedented gambit for a Socialist takeover. Few
businessmen have confidence in their corporate survival, never mind
expansion.