A DTV OTA signal occupies the same RF specturm as theevahle wrote:Anyway, I figured out that the additional stations are really extra channels that the main stations are using. Example: channel 10 now has 3 channels. Really great for work!
NTSC SDTV analog signal that it replaces.
A DTV signal, as for a satellite transponder or cable
TV headend channel, produces a 19.6Mbits/sec data
How that is used is entirely up to the service provider.
The bandwidth allocation is dynamic, and often changes
during a single broadcast. Four SDTV programs can
fit into one stream, so existing stations can have
multiple channels. PBS has been using these channels
for alternative programing for some years on
their DTV feeds.
Welcome to the new age of overwhelming choices!
Funny thing. We "Tivo'd" The 31st Kennedy Center
Honors and watched it later. The local news that
aired after the program was without sound from
the studio (the intro had theme music) on the HDTV
feed. After about 30 seconds someone switched to
the SDTV feed, with sound! The picture was
notably softer, but the studio is still in 4:3 aspect
and on HD has side graphics to fill the HD 9:16 aspect.
As we had extended the DVR event recording I
have this technical drama on disk for review.
During those first few minutes I'm sure the local
control room was in a panic as they tried to
isolate the no-sound problem. LAter they switched
back to the HDTV feed with sound.