[Ronja] Multiple receivers and transmitters

[Karel Kulhavy]

---- Gregory Maxwell <gmaxwell at gmail.com> schrieb:
> On Sat, Sep 20, 2008 at 1:09 PM, J.D. Bakker <jdb at lartmaker.nl> wrote:
> >>I have been thinking how to divide multiple heads between receivers
> >>and transmitters optimally, i. e. if we want to build N heads, how
> >>to get the maximum range.
> >
> > Given N transmitters and M receivers, it might be better (but more
> > complicated) to apply MIMO techniques.
> 
> 
> In radio the problem that MMIO solves is multipath: Between your TX
> and RX  there are obstructions which alter the signal, they shift
> phase in a frequency dependent manner, and creates nulls and peaks.
> MMIO uses spatially separated antenna which get different views of the
> multi-path environment.  You can then define a collection of filters
> which take advantage of the multipath to form separate channels and
> gain capacity.
> 
> For a fairly slowly amplitude modulated optical path like RONJA I
> would not expect there to be significant multipath. I do not believe
> MMIO would help.  But MMIO systems typically use efficient modulation
> systems  which would probably help ronja very much, but supporting
> them would be very costly.
> 
> Karel where does the noise come from in the receive head are we
> talking about optical background noise which would increase with
> increased collection area or is it primarily noise from the
> photodetector and amplifier?   If it is primary electronic noise,

In the night the noise is made mostly by the amplifier. In the
daylight the noise is mostly created by the quantization of the ambient light.

Karel