[opendtv] Re: News: TV Braces for the Apple Tablet

  • From: Albert Manfredi <albert.e.manfredi@xxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Sun, 7 Feb 2010 18:53:22 -0500

Craig Birkmaier wrote:
 
> The reason we chose poorly is that Broadcast TV
> is a WIRELESS service.
>
> It was abundantly clear in the early '90s that a
> new era of mobile communications was rapidly
> approaching. An era that would leverage
> packetized (IP) data, delivered via wireless
> networks. Rather than developing a standard
> optimized for mobile devices, the FCC chose
> poorly, holding onto the same criteria used for
> the original NTSC service - an outdoor antenna
> mounted to a 30 foot mast.
 
This is a simple case of your objectives being different from those of most 
other people. This includes the existence or FOTA TV at all, and it includes 
HDTV.
 
The 30' antenna height is a global standard used in determining stationary 
reception for TV. I agree that more emphasis should have been placed on testing 
for indoor reception, however the 30' or 10m criterion is used universally.
 
Had more emphasis been placed on indoor reception, I doubt that the -0 to +15 
usec capability of the 1st gen receivers would have been deemed adequate, and 
that would have accelerated the development of improved receivers, or made a 
stronger case for adopting something other than 8-VSB.
 
And also, if the FCC back in 1990 were as bent on forcing everyone to 
subscription TV services as you are, and as they are today, the idea of 
creating a greatly improved FOTA system would have made no sense at all. But 
here and in Europe, abolishing FOTA TV was not the goal.
 
As to mobility, one of the PRIMARY goals of the ATSC was to be able to transmit 
HDTV, and I continue to believe that was an EXCELLENT choice. Were it not for 
that decision, we likely would not have HDTV today. Cable was initially dead 
set against HDTV, as I recall (and I followed this very closely). As were you, 
let's not forget. If it hadn't been for the threat of OTA HDTV, we'd still be 
watching images not much better than NTSC.
 
Mobile TV has been an afterthought all over, and the development of ATSC M/H or 
of DVB-H are equally representative of this. The need to cram enough b/s over 
the 6 MHz channel for HDTV goes counter to the design decisions that would have 
had to be made for mobility.
 
But here's the bottom line. The way things have evolved for OTA DTV all over 
the world, in part to support carriage of multiple streams, and in part to 
support terrestrial HDTV, the versions of COFDM used in TV broadcast have 
gotten ever closer to the choices made in 8-VSB. In terms of b/s/Hz, and in 
terms of lowering the C/N requirements. France and Italy went to 64-QAM, and 
France went to the smallest possible GI of 1/32. The UK is heading in that 
direction, and developed DVB-T2. DVB-T2's primary reason for being is to lower 
the impact of the GI on spectral efficiency, and to lower the C/N margin needed 
for high spectral efficeincy. Both primarily in support of HDTV. So 8-VSB is 
just not nearly the obstacle you continue to insist it is. But, of course, 
that's because you see no call for HDTV or for FOTA TV.
 
Bert
                                          
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