Care tell us some more lies about how they're changing the 8VSB modulation
and no one should by a receiver?

He pulls that one out every few weeks. I think we're due for another round of
that one next week.

From "broadcast engineering" a fairly impartial look at what it would mean
if COFDM *WERE*
in fact adopted as the standard:

After reading that Dave, you have to be thankful we implemented the correct
modulation standard here in the U.S.!

Vidguy7 wrote:
Thanks charlie


Congrats BOB!!!! You finally found a friend!!! See, there is someone out there
that believes your ****.

Until he does some research on his own, unless he is yet another sock
puppet.

Matthew

Tim Keating wrote:

And is still happening today. It's the parallel nature of COFDM
carriers that works against it. It simultaneously xmits on hundreds
if not thousands of carriers at the same time.. An impulse noise
event of sufficient duration corrupts them all simultaneously. No
way around that problem other than to xmit the same data patterns over
and over again.

COFDM's problem with reoccuring impulse noise especially problematic,
since it also corrupts subsequent retransmissions.



Good explanation and hard to argue with. In addition, I think that the
following may be informative. As you probably already know, there is a
valid mathematical explanation describing the effect of impulse noise on
the frequency domain. COFDM basically transmits its data in the
frequency domain, where the spectrum is held constant for a specified
amount of time. Fourier analysis easily revels that an impulse in the
time domain (such as from mixers, blenders, sump pumps, etc) yields a
broad spectrum in the frequency domain. An impulse of the right duration
and strength is capable of disrupting many (maybe even all) COFDM
carriers. If too many carriers are lost, error correction will fail to
recover the data. On the other hand, 8VSB may not deteriorate nearly as
much for the same impulse noise. Since 8VSB is time dependent
modulation, the same impulse noise will only affect the portion where
the impulse and the modulation coincide. Typically, this is only a small
overlap area and error correction may have a good chance to recover the
data. At the lower VHF frequencies, impulse noise can be notoriously
severe; however most impulse sources yield less noise as the frequency
goes up; maybe reducing COFDM reception problems.