[opendtv] Re: Thomson readies solutions for U.S. Digital TV broadcast transition
- From: "John Shutt" <shuttj@xxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 12 May 2006 16:08:44 -0400
The drawback of E-VSB is that it doesn't directly address multipath. It
lowers S/N for the robust stream, but doesn't lower multipath
susceptibility.
The core technology of A-VSB is that a fixed data pattern is dispersed
before the R-S encoder and interleaver in such a way that it comes out of
the transmitter as a contiguous block in a known pattern. This hunk of
contiguous data can be used by a specially designed receiver as an extended
series of training signals to better track dynamic multipath. Doing this
requires control of the multiplexer, R-S encoder, data interleaver, and
8-VSB modulator as a unit, instead of separate building blocks.
A-VSB also includes the 1/2 or 1/4 rate Turbo modes for portable/mobile use,
that still eat away 2 or 4 standard bits for every robust bit as does
E-8VSB. A-VSB also time slices the robust data, ala DVB-H, for lower
battery consumption. The additional pseudo data training signals allow
this.
The neat thing is that new receivers can find the 120 newly created fixed
data pattern "SRS" supplemental training signals per VSB frame for enhanced
dynamic multipath tracking, while existing receivers simply ignore these
otherwise meaningless data packets. You do pay a payload price, however, so
the magic "19.4 for HD and not a bit less" means we can't use any of this.
Hey, if we were able to do HD in 13.4 Mbps and mobile in 1.5 Mbps, we would
have adopted DVB-T 6 years ago!
John
----- Original Message -----
From: "Richard Hollandsworth" <holl_ands@xxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Friday, May 12, 2006 3:19 PM
Subject: [opendtv] Re: Thomson readies solutions for U.S. Digital TV
broadcast transition
>I just posted pictures and description of the Samsung/Rohde-Schward Demo I
>saw at NAB2006:
> http://www.avsforum.com/avs-vb/showthread.php?p=7647247&#post7647247
> Claudia Kienzl at TV Technology was very skeptical re E-VSB finding a
> viable marketing strategy:
> http://www.tvtechnology.com/features/news/2006.04.24-n_E_VSB_in_search.shtml
> Esp given competition from DVB-H, COFDM et.al. for the mobile/handheld
> market... [Insert Bob Miller's usual rant here...]
>
> Other than announcements that there was an "A-VSB" demo at the DTV
> Hotspot, I haven't been able to Google ANYTHING on this ANYWHERE....
> Vaporware going Nowhere?????
>
> holl_ands
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts: