[opendtv] Re: Digital radios outstrip analogue

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "OpenDTV (E-mail)" <opendtv@xxxxxxxxxxxxx>
  • Date: Wed, 2 Mar 2005 11:07:19 -0500

Tom Barry wrote:

> Most people will not buy a portable radio that
> requires a rotor antenna on a 30 foot mast. ;-)

That's exactly right. Another way to put it is that
radio RF has to be modulated to promote robustness,
whereas TV RF has to be modulated to promote high
quality in the smallest possible bandwidth.

So digital radio operates at, say, no more than 1.3
b/s/Hz, whereas DTV is pushed up to 3.3 b/s/Hz.
Even the detuned Euro DTV plants, i.e. 16-QAM,
operate at 2.1 b/s/Hz.

Fortunately, audio requires much less bandwidth
than video, so no problem.

The directional antenna (and possible rotor) are
only there to compensate for the increased spectral
efficiency.

And by the way, radio is used in cars a lot.
Creating dense SFNs for radio is not practical,
because you'd soon lose your signal when traveling
outside the SFN boundaries. Radio broadcasters
can hardly afford to adopt a cell phone model (not
that cell phone coverage is 100 percent anyway).

Bert
 
 
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at 
FreeLists.org 

- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.

Other related posts: