[opendtv] Re: New Thread: What becomes of Legacy Analog Equipment
- From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Sat, 1 Dec 2007 09:41:41 -0500
The 2/3 trellis coding of 8VSB has to be maintained throughout data fields
in order for legacy receivers not to fail. So, use of another modulation
scheme during portions of the data field is precluded. This is what
prevented adoption of triple-PN1023 as a training signal.
Al Limberg
----- Original Message -----
From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Friday, November 30, 2007 9:19 PM
Subject: [opendtv] Re: New Thread: What becomes of Legacy Analog Equipment
> It might be interested in knowing how you believe you know so much about
the
> various proposals that TSG/S4 is processing. I am told that there are 10
S4
> subcommittees working on the proposals, grouped into four layers, but this
> stuff is being kept very close to the vest.
>
> From the drifts I get, there are some radical proposals out there, and
> supplementing 8-VSB using a different form of modulation would seem to
meet
> the ATSC rfp that started everything.
>
> John Willkie
>
>
>
> -----Mensaje original-----
> De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
> nombre de Manfredi, Albert E
> Enviado el: Friday, November 30, 2007 6:09 PM
> Para: opendtv@xxxxxxxxxxxxx
> Asunto: [opendtv] Re: New Thread: What becomes of Legacy Analog Equipment
>
> Craig Birkmaier wrote:
>
> > But we do not have DVB in the U.S. We cannot simply change a
> > few parameters of the modulation system to support MPH services.
> > For that we need to change the modulation standard, which means
> > that only NEW receivers will be able to use these bits.
>
> In truth, no different from DVB-H. So while I agree that DVB-T's COFDM
> "as is" is certainly more flexible than 8T-VSB, they have done to COFDM
> the same sort of thing that A-VSB and MPH (and at least 10 more
> proposals) have done to 8T-VSB. They have extended the physical layer in
> a backwards-compatible way.
>
> >> But AVC *could* be introduced just as "easily" as it is being
> >> in France and in the UK.
> >
> > Now how do I upgrade that integrated ATSC receiver that the
> > government forced me to buy?
> >
> > Oh yeah, just add a new STB...
>
> Exactly the same as Europeans with integrated DVB-T receivers will have
> to do. Except that here, since we already have HDTV, the urgency to
> introduce AVC does not exist. Besides, with integrated receivers adding
> a noise-level amount to price, who cares? Much like NTSC tuners now. Who
> cares if eventually it might not be used?
>
> Don't forget, for example, that by the end of 2008, no analog TV sets
> can be distributed to retailers in Italy. Some might interpret this to
> say that only monitors will be sold, but that's clearly not the case. As
> integrated DVB-T TVs already exist. You are assuming that DTT in Europe
> must mean a separate STB, but it's already not true today.
>
> > Those in Europe who have purchased wide-screen TVs (many
> > of which are HD capable), will simply need to buy an
> > affordable receiver for the new services. After a reasonable
> > period of time they will likely get rid of MPEG-2.
> >
> > Meanwhile those who invested in HDTV here in the U.S. may
> > see most of the bandwidth used for MPH services, with a
> > resulting decline in the attractiveness of the legacy ATSC
> > service.
>
> Again, in principle, the same could happen in Europe with DVB-H. If you
> think that mobile service will trump all other DTT, here and in Europe,
> no difference. For regular TV, we would all have to tie into an
> umbillical system, using either that system's STB or something like
> CableCard.
>
> > The important difference is that broadcasters in the U.S. are
> > using the spectrum to protect a legacy that has little to do
> > with DTV broadcasting ... Broadcasters in Europe are using
> > the spectrum to compete...
>
> DVB-T, as it is **in fact** being used in all of Europe, is to fixed
> home receivers. If anything, less than what ATSC can do here (no HDTV
> there, and very low power transmitters requiring outdoor antennas more
> regularly). The difference here is that we have a much more aggressive
> pay-TV industry, and a conflict of interest for broadcasters, caused by
> must-carry and retransmission consent.
>
> You keep suggesting some sort of difference that does not exist, Craig.
> Those countries in Europe that want to offer mobile service are talking
> in terms of DVB-H. Their DVB-T transmitters are way too low power, for
> one thing, to provide a credible mobile service. Even if it might work
> in certain small areas.
>
> I understand your desire to grab the TV spectrum for mobile service. It
> would affect European DTT exactly the same as US DTT. They would go to
> DVB-H, we could do likewise, or go to one of the new VSB variants.
>
> Bert
>
>
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