[opendtv] Re: White paper from CEA
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Tue, 1 Nov 2005 11:56:56 -0500
Craig Birkmaier wrote:
> > So here we had indications that a properly
> > functioning suppressed carrier scheme could be
> > designed, with the advantages in spectrum efficiency
> > and power that have been well known to radio
> > engineers since the 1920s, and certainly by the
> > 1930s.
>
> You still don;t get it Bert. There ARE NO ADVANTAGES
> in spectral efficiency and power levels with ATSC...
Power and spectral efficiency, I said.
On spectral efficiency, there are no advantages compared
with single-carrier 64-QAM, but there are still
advantages compared with COFDM using 64-QAM. It's true
that the spectral efficiency advantages of SSB, in the
1930s, were compared with AM-DSB, not compared with QAM.
So you're almost right that spectral efficiency doesn't
play a big role here, but it's still a factor.
On power, there are no full power carriers in 8-VSB. As
opposed to dozens in 2K COFDM and over 100 in 8K.
Big sticks have nothing to do with this, as we have
discussed about a zillion times. That's an orthogonal
discussion, which you seem to forget on a periodic
basis.
COFDM's main objective is to combat multipath. For a
terrestrial system, that is certainly very important. But
if multipath can be tamed with other means, without going
to ridiculous extremes, then just like anything else,
there are other considerations that one should not
dismiss outright.
If we are stuck with 8-VSB, which we certainly appear to
be, IMO it's far better to make the best of it rather than
continue to feel sorry for ourselves.
Bert
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