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Mobile DTV receiver in Japan

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Anonymous
January 20, 2005 10:26:45 PM

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

"It supports terrestrial digital tuners to be released during 2005."

http://www.techjapan.com/Article821.html

Notice the antenna. Not a Yagi, Not directional but will it work? Yes!
Just like the cell phones that will be on the market with even smaller
antennas this year.

But if you listen to Mark or Doug this isn't possible. To much impulse
noise.

Where was the impulse noise in this video shot in Manhattan from a
single 100 Watt transmitter? Manhattan has to rival Tokyo for impulse
noise but there is not interference because of impulse noise here.

www.viacel.com/bob.wmv

The ONLY instance of impulse noise interference that I have witnessed
was with 8-VSB right here in Manhattan. I turned on a circular lamp
right next to my LG receiver and was able to cause a hiccup in the
reception every time. No big deal but it didn't happen with my COFDM
receiver.

The two things that 8-VSB proponents harp on as problems with COFDM are
NOT. Power and impulse noise. Doug says that COFDM needs twice the power
for the same coverage but the UK uses about a 32nd of the power for the
same coverage as US stations say is the norm for 8-VSB. I guess they are
trying to over power the multipath signals but it doesn't work because
the multipath signals also increase in power at the same rate.

Bob Miller
Anonymous
January 20, 2005 10:26:46 PM

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

Bob Miller wrote:

Nothing of interest.



The US has an DTV modulation standard. It is 8-VSB. It is not going to
change.

Matthew
Anonymous
January 20, 2005 10:26:46 PM

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

Bob Miller wrote:
>
>
> Where was the impulse noise in this video shot in Manhattan from a
> single 100 Watt transmitter?

What was the bitrate of teh transmission? It if was
not in the 15 Mb/sec aread OR HIGHER, then COFDM has
of course less of a problem with impulse noise. If you
are talking mobile use, OF COURSE there is less impulse noise,
since you are using a very low bitrate and lots of error correction,
to make it work at all.

Except at low VHF one does not hear about impulse noise
problems in the US. If you visit discussion from
Australia or England, it is a very big subject indeed.

Doug McDonald
Related resources
Anonymous
January 21, 2005 1:37:19 AM

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

On Thu, 20 Jan 2005, Doug McDonald wrote:
> What was the bitrate of teh transmission? It if was
> not in the 15 Mb/sec aread OR HIGHER, then COFDM has
> of course less of a problem with impulse noise.

It's 15fps video content being transmitted over the W-CDMA cell phone
network. It is not terrestrial digital TV.

Bob Miller insists upon confusing the two, exploiting the fact that
translations are often ambiguous.

-- Mark --

http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.
Si vis pacem, para bellum.
January 21, 2005 2:40:19 AM

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

"Bob Miller" <robmx@earthlink.net> wrote in message
news:VBTHd.1181$r27.137@newsread1.news.pas.earthlink.net...
> "It supports terrestrial digital tuners to be released during 2005."
>
> http://www.techjapan.com/Article821.html

It's not exactly unqiue, there has been mobile DVB for a while :-

http://www.scmmicro.com/dvb/mobile_terrestrial.html
http://www.hitopcomm.com/products/mob2-t1200.html

The Hitop reciever seen in the middle of this page was the earliest one I
remember :-
http://www.br-online.de/br-intern/technik/dvb.html


Az.
Anonymous
January 21, 2005 4:06:06 AM

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

"Doug McDonald" <mcdonald@SnPoAM_scs.uiuc.edu> wrote in message
news:csp9le$e4m$1@news.ks.uiuc.edu...
> Bob Miller wrote:
>>
>>
>> Where was the impulse noise in this video shot in Manhattan from a single
>> 100 Watt transmitter?
>
> What was the bitrate of teh transmission? It if was
> not in the 15 Mb/sec aread OR HIGHER, then COFDM has
> of course less of a problem with impulse noise. If you
> are talking mobile use, OF COURSE there is less impulse noise,
> since you are using a very low bitrate and lots of error correction,
> to make it work at all.
>
> Except at low VHF one does not hear about impulse noise
> problems in the US. If you visit discussion from
> Australia or England, it is a very big subject indeed.
>

Not really a big discussion in the UK any more. The small transmitter power
increases, coupled with the move to 16QAM (18Mbs) have made the signal more
robust, and the more recent Freeview boxes (as opposed to the first
generation ON/ITV Digital boxes) have much better impulse noise performance
as well.

Sure 18Mbs in a UK channel spacing should be robust - but our power levels
are still very low.

I get error free reception of both the 4 16QAM and 2 64 QAM multiplexes from
a reasonable (but not specially installed for digital) rooftop aerial from
the 20kW transmitters used for Crystal Palace digital TV reception, though I
am on the edge of the offical (editorially) analogue coverage region from
the same transmitter (though I get an excellent analogue picture as well)
from its 1000kW transmitters. I get acceptable - though not error free -
reception via a Silver Sensor set-top aerial for digital TV as well. My
line of sight distance is 30 miles.

My mother lives on the South Coast, where digital TV transmission has to be
at extremely low powers to avoid interference with France, Belgium and The
Netherlands. Her nearest digital TV transmitter is running at 2kW, and she
has a reasonably Sony DVB-T receiver and a roof-top aerial. I didn't see a
single digital TV glitch in the time I spent at her house over Christmas.
The corresponding analogue transmittes from this site are 100kW - but aren't
actually deemed good enough for her viewing location, so there is a 200W
relay of the main 5 analogue channels for her location.

Impulse noise WAS a real problem with 64QAM, the lower power levels and
early receiver designs deployed in 1998. In 2005 the current Freeview
receivers and transmission system are far less problematic - as you'd
expect.

I'm not saying it is perfect - but it is proving a really popular consumer
product (good Christmas receiver sales), and the channel line-up and lack of
subscription (apart from a tiny number of channels) have meant it is
converting people to digital who would otherwise would have stuck with just
the standard 5 analogue OTA channels.

In the UK our transmitter network is obviously very different to the US - we
have a network of national stations with minor regional variations, and a
totally different geography to cope with. Historically we've had excellent
analogue OTA coverage of a very high percentage of the UK population - and
have employed decent aerial installations rather than cable TV - so many
people (though by no means all) have decent rooftop aerials pointing at the
correct transmitter site for decent reception of both analogue and now
digital TV.

Steve
Anonymous
January 21, 2005 4:54:22 AM

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

Aztech wrote:
> "Bob Miller" <robmx@earthlink.net> wrote in message
> news:VBTHd.1181$r27.137@newsread1.news.pas.earthlink.net...
>
>> "It supports terrestrial digital tuners to be released during 2005."
>>
>>http://www.techjapan.com/Article821.html
>
>
> It's not exactly unqiue, there has been mobile DVB for a while :-

The unique part is that it is portable DTV with a small omni antenna for
use in Japan with ISDB-T. There are others and will be hundreds of more
models.
>
> http://www.scmmicro.com/dvb/mobile_terrestrial.html
We demonstrated a PCMCIA card receiving DVB-T in Toronto years ago well
before SCM even was thinking of it even though we were asking them for
such a unit.

> http://www.hitopcomm.com/products/mob2-t1200.html
We own two Hitop units like the one in the pic and two other models for
a total of 6 units. All the receivers in the video
www.viacel.com/bob.wmv
are either Hitop (Taiwan) or Dibcom and Dibcom (France) makes the guts
of the Hitop.

Bob Miller
>
> The Hitop reciever seen in the middle of this page was the earliest one I
> remember :-
> http://www.br-online.de/br-intern/technik/dvb.html
>
>
> Az.
>
>
January 21, 2005 5:22:01 AM

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

"Stephen Neal" <stephen.neal@nospam.as-directed.com> wrote in message
<
> Not really a big discussion in the UK any more. The small transmitter power
> increases, coupled with the move to 16QAM (18Mbs) have made the signal more
> robust, and the more recent Freeview boxes (as opposed to the first generation
> ON/ITV Digital boxes) have much better impulse noise performance as well.

The power increases may of had an impact at Crystal Palace (now at a whopping
20kW!), however it seems the chipsets in post-ITVdigital boxes have done more in
terms of reception and eliminating impulse noise than any infrastructure
changes.

At other sites like Sutton Coldfield things haven't progressed at all, it was
trailed at 12kW, also 10kW for a while but according to the Beeb site it's back
at retro 8kW with only Mux D at 10kW, probably due to it being out of group for
the aerials. It's not exactly an inconsequential site, obviously the progress in
boxes are bailing them out, cutting the power by 2/3 certainly hasn't brought a
flurry of complaints.

These ridiculously low ERP's have sweet f.a. to do with minimising analogue
interference, I've yet to see a 50kW or even 100kW mux affect a 1MW PAL
transmission and you could probably put 20kW on channel without anybody
noticing!

So the low powers must be a dastardly plan to ;
1. preserve bandwidth for later sale through the hideous duplication and
rationing of frequencies.
2. the transmission companies have been sacked all their engineers and the
entire network is run by an overworked monkey*
3. to play a sadistic game of 'how low can we go'.
4. support the sale of coax, thus propping up ex-colonies that mine copper.
5. A government desperately attempting to undermine the service at behest of
evil Murdoch yet somehow it keeps failing (even less power!).
6. run main sites on less juice than an electric kettle.
7. all of the above.


Az.

* http://www.historic-uk.com/Ape.jpg
Anonymous
January 21, 2005 1:02:25 PM

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

Mark Crispin wrote:
> On Thu, 20 Jan 2005, Doug McDonald wrote:
>
>> What was the bitrate of teh transmission? It if was
>> not in the 15 Mb/sec aread OR HIGHER, then COFDM has
>> of course less of a problem with impulse noise.
>
>
> It's 15fps video content being transmitted over the W-CDMA cell phone
> network. It is not terrestrial digital TV.
>
> Bob Miller insists upon confusing the two, exploiting the fact that
> translations are often ambiguous.

I am not confusing anything. You keep bringing up 15fps cellular video
on demand junk because it serves some purpose that I do not understand.
I have never brought it up. I am talking only about broadcast OTA
digital DTV to cell phones that can be a whatever data rate and frame
rate the broadcaster wants. I have not heard of them doing 15fps. That
is a rate that cellular companies need to use since their spectrum is
limited and each customer uses spectrum for every stream of video. NOT
so with broadcast where the same spectrum is used once to reach one or a
billion phones and there is no need to limit the frames per second.
Simply a non issue that Mark keeps confusing himself with I guess.

There is no translation problem. I talk directly with Japanese engineers
who are fluent in English and the press releases are unambiguous as
well. Japan, Korea and Europe will see DTV OTA to cell phones using
ISDB-T in Japan this year, DMB-T in Korea this year and DVB-H in Europe
next year.

Bob Miller
>
> -- Mark --
!