Re: ATSC modulators

[isw <isw@xxxxxxxxxxx>]

In article
<c49bfe02-00a5-4609-8bfe-deb2056a6eb6@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,
 beaver <ed@xxxxxxxxxxxx> wrote:

> I currently place video sources onto unused (analog) channels, and
> send that along with the incoming RF around the house.
>
> If I were to switch to digital (ATSC), I would like to also distribute
> the video sources (PC, DVD, CCTV cameras, etc) onto unused ATSC
> channels also.  This is why I seek something such as an ATSC
> modulator.

ATSC uses (as you already know) digital modulation. A digital modulator
is orders of magnitude more complex, and therefore probably orders of
magnitude more expensive, than an analog modulator. I suspect that the
only ones available at this time are professional units.

It may be that at some time in the future, a "consumer grade" ATSC
modulator will be available, but I wouldn't expect it any time soon.

Also, your cable operator may not even use ATSC modulation, which (it is
claimed) was chosen for its over-the-air performance. It is not the same
modulation method that cable operators have been using for digital
channels, and furthermore it is not even necessary in the benign
environment inside a coaxial cable. I'd be surprised if your cable
company was using anything other than 64-QAM or 256-QAM.

In addition to a digital modulator, you would need to have MPEG encoders
for each of your local video sources, and an MPEG transport-stream
multiplexer to combine them and feed them to the ATSC modulator.

Isaac