[opendtv] Re: Ofcom paves the way for UK HD on DTT
- From: Albert Manfredi <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Sat, 5 Apr 2008 17:57:57 -0400
Craig Birkmaier wrote:
>>> But is the Ofcom proposal using MIMO?
>>
>> DVB-T2, so yes.
>
> Are you sure?
Okay, I understand what you and Olivier are getting at.
No, I'm not sure that DVB-T2 will adopt the scheme presented in the two BBC
research papers. But then again, Ofcom did not mention DVB-T2 explicitly.
Here is what Ofcom said:
"Ofcom proposes to clear one of the three multiplexes currently used for public
service broadcasting (Multiplex B, licensed by Ofcom to BBC Free to View Ltd).
The existing channels on this multiplex will be relocated to use the spare
capacity on the other multiplexes. Once this is complete, Multiplex B will be
upgraded to use new technologies and standards. The extra capacity on the
reorganised multiplex will allow broadcasters to introduce new services,
including high-definition channels."
In the context of those two BBC research papers, dated 2006 and 2007, which no
doubt Ofcom is familiar with, transmitting 4 HD streams in an 8 MHz channel is
not all that amazing. I should not have mentioned DVB-T2.
[On MPH]
> I see that the spectral efficiency is reduced to make robust
> operation possible with VSB. We already demonstrated
> equivalent mobile reception in Las Vegas, in 2000, with plan
> vanilla DVB-T, with a payload that was equivalent to 8-VSB
> without any MPH enhancements.
Uhh, no.
Added robustness always mean lower spectral efficiency, at a given power level.
I already showed that the C/N margins for A-VSB robust streams were plenty
competitive with any other modulation standard, and even quite close to the
Shannon limit. Back when that info was provided to the list.
There's not much left to discuss, once you are within less than 2 dB of the
Shannon limit, as A-VSB is in its robust mode with diverse receive antenna. No
point dredging up old comparison tests in the bad old days of inadequate 8-VSB
receivers (which are still not where they should and could be, IMO).
Bert
_________________________________________________________________
Pack up or back up–use SkyDrive to transfer files or keep extra copies. Learn
how.
hthttp://www.windowslive.com/skydrive/overview.html?ocid=TXT_TAGLM_WL_Refresh_skydrive_packup_042008
----------------------------------------------------------------------
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: