[opendtv] Re: From Broadcast Engineering - WRAL tests mobile DTV
- From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 7 Aug 2008 23:10:45 -0700
You cannot draw conclusions until the standard has been released. However,
I believe that public prints have put the o/h at close to 4.5 mb/seconds for
one service, and IIRC, 9 for 2 services. Maybe the term isn't exactly
services, but I can only refer to things which have been mentioned publicly.
John Willkie
-----Mensaje original-----
De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Bob Miller
Enviado el: Thursday, August 07, 2008 9:09 AM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Re: From Broadcast Engineering - WRAL tests mobile DTV
That is what I would like to know. How far was I off last year when in
technical ignorance but from a good source I put out numbers on what
one 8-VSB mobile modulation would cost in bits. What are the numbers?
What is the overhead and what is the % of bits that are real at what
robustness levels?
Anybody care to compare to DVB-T or H or CDMB-T or is it a big secret
because it is so bad.
Bob Miller
On Thu, Aug 7, 2008 at 11:24 AM, <dan.grimes@xxxxxxxx> wrote:
>
> What is the reason for only getting one 600 Kb/s and one 300Kb/s channel
out
> of 4.5 Mb/s? Are the rest of the bits required for overhead or did they
> just not fill all the M/H channels possible in the 4.5 Mb/s subchannel
> bandwidth?
>
> Dan
>
>
>
> Tom Barry <trbarry@xxxxxxxxxxx>
> Sent by: opendtv-bounce@xxxxxxxxxxxxx
>
> 08/06/2008 08:41 PM
>
> Please respond to
> opendtv@xxxxxxxxxxxxx
> To
> opendtv <opendtv@xxxxxxxxxxxxx>
> cc
> Subject
> [opendtv] From Broadcast Engineering - WRAL tests mobile DTV
>
>
>
>
> Supposedly from Broadcast Engineering though I copied it from AVS
> <http://www.avsforum.com/avs-vb/showthread.php?t=1056025>. I'm not sure
> I understand it correctly but it looks like they got a total of 900
> kbps (2 channels, 300+600) after error correction overhead from using a
> total of 4.5 mbps of the channel bandwidth.
>
> - Tom
>
> ---------------------------------------------------
> From Broadcast Engineering - WRAL tests mobile DTV
> Broadcast Engineering Mobile TV Update
>
> WRAL tests mobile DTV
>
> Users in Raleigh-Durham reported reliable signal reception in most parts
> of the station's existing coverage area.
>
> WRAL-DT, the CBS affiliate in Raleigh-Durham, NC, owned by Capitol
> Broadcasting Company (CBC), conducted a series of mobile DTV tests last
> week using the Mobile-Pedestrian-Handheld (MPH) system promoted by
> Harris Broadcast and others. Hosted by CBC's New Media Group, the tests
> featured seven handsets given to station executives living in different
> parts of the state. Users reported reliable signal reception in most
> parts of the station's existing coverage area.
>
> To kick off the July 21-25 trial, the station hosted a reception last
> Tuesday in which about 50 participants were driven in a bus around the
> area with prototype LG Electronics mobile handsets that featured
> MPH-compatible reception chips inside. Signal reception of two channels
> (half rate at 600kb/s and one-quarter rate at 300kb/s) using about
> 4.5Mb/s (including turbo coding) of the station's 19.4Mb/s on-air DTV
> stream was reportedly strong everywhere they went during the 10-minute
> ride - even at 70 miles per hour.
>
> The goal of the service, according to John Harris, WRAL's director of
> programming, is to extend the reach of the station's television channel,
> and make it available everywhere our viewers are. The initial plan is to
> simulcast the on-air DTV signal. WRAL-TV broadcasts CBS network and its
> own local programming in the 1080i HDTV format as well as in SD digital.
>
> "We're excited about the possibilities," John Harris, WRAL's director of
> programming, told Broadcast Engineering. "The priority is to offer
> WRAL's TV signal in another way, in another place. I took one [handset]
> east of the station and I just kept driving until the signal dropped
> out. I got pretty far before that happened, so I can see the potential
> of this service."
>
> LG Electronics, Zenith Electronics and Harris, all proponents of the MPH
> scheme, helped out with the field trials. WRAL-DT uses a Harris Sigma
> CVD UHF transmitter, with an MPH module, for the weeklong test.
>
> In a statement, James F. Goodmon, CEO of CBC, said "mobile DTV
> broadcasting enables WRAL to better serve our viewers, communities, and
> advertisers by providing a strong combination of anywhere access,
> two-way communication, and mobility."
>
> In 1996, Harris worked with WRAL-DT as one of the first DTV stations in
> the country. Two years later, when John Glenn made his historic return
> to space, Harris worked with WRAL to conduct the first live HDTV
> broadcast of a space shuttle launch to audiences nationwide. Now, the
> station is the first to promote mobile DTV service in the state of North
> Carolina. WRAL predicts that more than 200 million portable devices will
> be sold in 2008, although few if any will have the necessary MPH
> reception chips inside.
>
> WRAL-TV and Capitol Broadcasting Company are part of the Open Mobile
> Video Coalition (www.openmobilevideo.com), a nationwide group of
> broadcasters driving the deployment of mobile digital broadcast
> television. Commercial deployments are forecast for 2009. The group
> hopes to have an established standard available to broadcasters by the
> February 2009 analog shutoff date.
> --
> Tom Barry trbarry@xxxxxxxxxxx
>
>
>
>
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