[opendtv] Re: With CFP, Air Test, ATSC 3.0 Off And Running | TVNewsCheck.com

  • From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Sat, 30 Mar 2013 11:25:56 -0500

One way to reduce PAPR is to use 128QAM and 512QAM with cruciform symbol
constellations rather than 64QAM and 256QAM with square symbol
constellations.  The 128QAM and 512QAM can be used with single-time
retransmission to get back AWGN performance.  Single-time retransmission
(used by DVB-T2 in their rotated constellation option) overcomes burst noise
and long drop-outs in received signal strength.  If circular FFT is rotated
one half revolution as between two transmissions, deep selective fading is
overcome, too.

Allen
----- Original Message ----- 
From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Thursday, March 28, 2013 4:48 PM
Subject: [opendtv] Re: With CFP, Air Test, ATSC 3.0 Off And Running |
TVNewsCheck.com


> Mark Aitken wrote:
>
> > I was surprised no one picked up on this...
>
> > http://bit.ly/11Rhmm2
>
> Hey Mark, I've been meaning to ask you what you are finding.
>
> The only aspect of any switch to DVB-T2 (or any form of COFDM) is that
works against you is, the effect on tight packing of TV markets. More so if
the FCC goes through with their plan to grab more TV spectrum.
>
> I'm intrigued by your comment on being able to ignore any legacy COFDM
use, but I'm not sure what you're considering to reduce PAPR of DVB-T2
(which should already be lower than that of DVB-T1).
>
> I have a real stake in this. If, in order to reduce on-channel
interference, you need to reduce average power with DVB-T2 compared with
ATSC 1.0, I might just lose your two signals! At least, if I intend to keep
the antenna in the fireplace!
>
> I'm also very curious as to what other organizations are thinking about
ATSC 3.0.
>
> As to UHDTV, I think that's a completely orthogonal discussion. You can do
UHDTV with ATSC 1.0 or anything else that gets reasonably good b/s/Hz. Just
migrate to H.265. The modulation scheme is a secondary issue in this. It's
almost annoying to see the two discussion becoming conflated (not accusing
you of this, btw, just commenting on the article). Much like HDTV was
conflated with ATSC. Education is always better than obfuscation, even if
obfuscation might seem the easier way to get through to the clueless.
>
> Bert
>
>
>
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