5 Nov
2005
5 Nov
'05
4 p.m.
On Sat, Nov 05, 2005 at 09:23:05PM +0200, Juhana Sadeharju wrote:
Thanks for the tip on "diversity reception". Yes, I got the
idea from astronomer's systems.
Normally 'diversity reception' means to combine the signals from
2 or more receivers to obtain a result that has a better S/N ratio
(or less missing data) than either of the inputs.
What the astronomers are doing is even more tricky. They combine
signals from distant receivers not to get a better signal but to
improve the angular resolution of the antenna, by 'synthesising'
the effect of a very big one. It's called 'interferometry' and
can get quite complicated.
My test plan was to record the same music station at
two cities
(apart 200km). Then timescale and align the digitized (1 or 2 hours)
recordings manually. And then do the thing.
If both recordings are complete and have about the same quality, the
best you can obtain is a 3 dB gain in S/N (for analog transmissions -
for digital the picture is more complicated).
--
FA