"Sal M. Onella" wrote in message
...

"MRW" wrote in message
...
I'd like to know about the DVB-T standard, but I get confused when it
comes to configuring a DVB-T system for a Single Frequency Network
topology. I've read that normally for an 8MHz bandwidth using 2k mode
about 1700 carriers are possible. Does this translate to 1700
individual programs?

I think I can probably answer this question if I find a good tutorial
on COFDM. I've found some on Google, but I haven't found one that
explains simply how it is possible to have multiple carriers in a
single channel.

Crossposted for a useful purpose.

The alt.video.digital-tv newsgroup has been home to numerous discussions
of
COFDM and the various ways it's being employed. It was a contender for US
broadcast DTV but it lost out to 8VSB in a decision process that some
people
said was political -- or worse. One of the leading proponents of COFDM
posted to alt.video.digital-tv as "Bob Miller," although he has nothing
there currently.

COFDM has some disadvantages. For the same quality received signal it
requires more peak power at the transmitter than 8VSB, but TV transmitters
are peak limited. It is more susceptible to impulse noise, and you can't
have a full power COFDM signal on an adjacent channel to an analog NTSC or
PAL signal. My understanding is that the last mentioned is causing
complications in some European countries with the analog to digital
changeover. They will have very little HD until the analog service has been
shut down.

Bob Miller has ulterior motives. His company wants mobile digital TV
transmission to moving cars, which 8VSB has problems with (I think because
of the equalizer which takes several seconds to train. In a moving vehicle
it would be continuously hunting)).

Tam

Bob Miller may have the material you want, given that he
has
been a vocal advocate. The viacel.com web site comes up blank; I hope
that
email address isn't a dud. Good luck.