ATSC 8VSB SFN News

Archived from groups: alt.video.digital-tv (More info?)

"K. B." <hotmail.com@lis2lis2> wrote in message
news:4163803f.1306182@netnews.worldnet.att.net...
> <http://broadcastengineering.com/news/highlights/atsc-transmitter-networks-20041004/>

I was under the impression that an on-channel repeater relating to "difficult
terrain" isn't actually a SFN since you're relying on the topography to shield a
shadow area from the main TX site, you can do this with analogue transmissions
for example.

You can define a SFN as being able to serve even built up areas, e.g. a flat
area with two transmitter sites either side of town operating on an equal basis
in an SFN, receivers can make use of both signals simultaneously or from a
single station whilst disregarding symbols from the other site if they're
outside the guard interval. Quite different from a small on-channel repeater in
the shadow of a hill.


Az.

Archived from groups: alt.video.digital-tv (More info?)

K. B. wrote:
> On Wed, 06 Oct 2004 22:40:35 GMT, "Aztech" <az@tech.com> posted:
>
>
>>"K. B." <hotmail.com@lis2lis2> wrote in message
>>news:4163803f.1306182@netnews.worldnet.att.net...
>>
>>><http://broadcastengineering.com/news/highlights/atsc-transmitter-networks-20041004/>
>>
>>I was under the impression that an on-channel repeater relating to "difficult
>>terrain" isn't actually a SFN since you're relying on the topography to shield a
>>shadow area from the main TX site, you can do this with analogue transmissions
>>for example.
>
>
> Interesting statement in the ATSC document:
>
> "5.3.2.2 Current Receiver Designs
> Whether these improved features are adequate for SFNs remains to
> be seen."
>
> Must we now wait for 6th generation ATSC 8VSB receivers?
>
> Kirk Bayne
> alt.video.digital-tv Home Page
> <http://www.geocities.com/lislislislis/avdtv.htm>

I would think so based on what I have seen with a 5th gen receiver.
Better but I will believe it when I see it, an 8-VSB SFN.

Remember whole countries already use COFDM in SFN mode. No example of a
working 8-VSB SFN exist just vague test.

BTW why are we even bothering with such outmoded tech? What is it that
makes 8-VSB so desirable that we have now waited six years for an
"improvement" called 5th gen? Why don't we join the rest of the world
with a real modulation not one in development?

8-VSB is still trying to get to where COFDM was in 1998. My prediction
is that it will still be trying on the day it expires whenever that is.

Archived from groups: alt.video.digital-tv (More info?)

John Dyson wrote:
> "Bob Miller" <robmx@earthlink.net> wrote in message
> news:IWx9d.9331$M05.7490@newsread3.news.pas.earthlink.net...
>
>>BTW why are we even bothering with such outmoded tech? What is it that
>>makes 8-VSB so desirable that we have now waited six years for an
>>"improvement" called 5th gen?
>>
>
> COFDM and its derviatives have been around for a very long time. 8VSB for
> this application is quite new.
>
> Note that 8VSB works MUCH MUCH better than you had ever predicted, and
> there is no reason why it won't work better yet in the future. Before the
> 5th generation, 8VSB had some advantages for fixed HDTV applications over
> COFDM, and now it is going to blow away COFDM for fixed HDTV applications.

8-VSB has NO advantages for fixed reception or anything else. It's only
value is to those who hold IP royalty rights to 8-VSB and the revenue
streams that they kick off. 8-VSB will now do very well in the US
because of the new minimally acceptable 5th gen receiver. Ironically
this will finally release spectrum for use by COFDM and then when the
two compete in the same market, something 8-VSB proponents have moved
heaven and earth to avoid, COFDM will blow away 8-VSB in the
marketplace. Broadcasters will then demand a change of modulation,
quietly, and it will be granted with NO thought to the legacy 8-VSB
receivers or the best interest of the public. The public interest is the
last thought the FCC or Congress has. It is the one they read on the
teleprompter and that is the only place you will find the public interest.
>
> Anything other than fixed DTV applications is a misuse of spectrum, and Bob, you continue to advocate such misuse. You'd be alot happier if you'd just buy your spectrum space, so that you can pollute all of the mass transit with
> your saturation adverts.

The Holy Grail is "fixed reception" no thought that mobile or portable
could be usefully. There is a new prototype projector that is literally
small enough to fit in your pocket, uses little power and can throw a
20" by 30" HDTV image on any white surface. We will have one in a month
or so. It can use the power of a laptop or even a PDA or cell phone
(probably with a fuel cell). They say the production model will be the
size of a credit card and one inch thick. In Japan and Europe they
already have cell phones that can receive DTV. Now they will be able to
watch HDTV just about anywhere with simple projectors, HD glasses all
with receivers so small they are a non-intrusive part of a cell phone
with simple antennas.

The 5th gen receiver is a clutsy and very late to arrive minimally
acceptable receiver. Nothing to be proud of. We still should convert to
COFDM instead of staying the course with 8-VSB.

The future is a long time, very little of it will be occupied by such
bad technology as 8-VSB, and many uses will be found for a high
resolution like HDTV. The rest of the world will enjoy much of this
before we do. Many of them think we are quaintly backwards already in
our patchwork cell phone industry. Now they will find us extremely
backward in our digital TV industry.

By 2008 China, Japan and Europe will be the state of the art in DTV,
including HDTV. We will probably have our Congressional hearings on DTV
degenerate into why we are so backward by then.

Bob Miller
>
> Are you the same Bob who has been rejected from various forums for your
> dishonest spin?
>
> John
>
>