Michael Coslo wrote:
On 3/3/12 9:40 PM, wrote:
You only have to read as far as:
"This novel radio technique allows the implementation of, in principle, an
infinite number of channels in a given, fixed bandwidth..."
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^
to know it is crap, in principle or otherwise.
Yeah, I read further though. It's one of those things where infinite
bandwidth requires infinite power, And almost infinite power pretty quickly.
This is a relative of the phase shift idea, where we can make smaller
and smaller shifts until we have amazing channel carrying capacity.
Too bad it doesn't work in the real world. Zero Point energy is more likely.
It seems you make the mistake of equating a "channel" in terms of
communication theory to a slice of bandwidth on RF. Those are
clearly not the same thing.
One can use the same RF bandwidth slice as a channel multiple times,
and thus transfer many times the amount of information such a communication
channel can theoretically carry.
Examples:
- horizontal and vertical polarisation of EM waves
- beam antennas beaming in different directions
- pairs of sending/receiving antennas that are shielded from eachother
e.g. by the curvature of the earth
Of course, the Shannon theory considers all those different instances a
different channel, each of which can carry a certain amount of information.
But as the user/licensee of a slice of spectrum, it is tempting to call
that slice of spectrum a channel and welcome any way of transferring more
information through it that was thought possible before.
And this seems to be what is going on here.
Of course, practical limitations on separation will make it impossible
to realize a large gain from this, let alone "an infinite number". But
that is just the journalists ignorance part of it.