[opendtv] Re: Let them eat cake (and ATSC while they're at it)

  • From: "John Shutt" <shuttj@xxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Mon, 16 May 2005 19:17:02 -0400

Terry,

----- Original Message ----- 
From: <tjharvey@xxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Monday, May 16, 2005 6:45 PM
Subject: [opendtv] Re: Let them eat cake (and ATSC while they're at it)


>
>> "In Las Vegas, KFBT-DT (on Channel 29's)digital facility will transmit a
>> multiplexed 6 Mbps HDTV (720p) and signal a "live" 1.5 Mb/s SDTV (encoded
>> with TANDBERG hardware) of the KFBT on-air product. According to those 
>> close
>> to the demonstration, the 2-VSB datastream will have a total payload of 9
>> Mbps."
>>
>> COFDM and DVB-T could duplicate LINX's feat in 1999, with a much higher
>> payload.  Dream on.
>>
> That is not true. DVB-T could not deliver 9 Mb/s without a substantial 
> increase in transmitter power. And at 9 Mb/s the transmission robustness 
> would be substatially reduced. At best it would be a toss up and due to 
> COFDM inefficient use of bandwidth, 2VSB would likely be superior.

Middle of the 16-QAM chart for 6 MHz channels is 3/4 code rate, 1/8 guard 
interval, for 12.4 Mbps.  I'd stack that up against 2-VSB in a city bus.

> Remember at that time (1999) DVB-T diversity reception and hierarchal 
> modulation were still only a dream. So dream on.

I didn't mention HM COFDM, but it was demonstrated at the April 2000 NAB, so 
it was a year late.  Sorry.  It still beat the 2 VSB demo by 3 years, and 
there still isn't any 2-VSB product available.  Nor will there ever be. 
Plenty of HM COFDM with diversity reception available worldwide, however.

I am dreaming on.

John 


 
 
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