[eagle] Re: IMD, Phase Noise, a New Spur, and EMI suggestions

Robert McGwier rwmcgwier at gmail.com
Thu Jun 28 05:00:57 PDT 2007


If we have had this discussion before,  forgive me.  I have misplaced 
both the interaction and my memory.

What is the generator for the "Pave Paws" source?  I ask this because 
the phase noise for the "Pave Paws" source does not seem to be included 
in your consideration.

Pave Paws is a pulsed instrument.  It will not have its energy 
concentrated at a single frequency.  Its energy will be spread 
considerably and much of that energy will fall outside of the front end 
filter of the 70 cm RX.   A more realistic test would compute that a 
-70.2 dBm Pave Paw signal will put  (say) -90 dBm inside our passband 
and further, it will be on/off.  Since it is on/off,  there will be gaps 
where the amateur signal is not drastically impacted.  A receive system 
on the ground, necessarily narrow band,  will provide processing gain. 
If we do a good job of writing code, and we do not run out of processing 
cycles, it would be nice to do pave paws pulse detection and subtraction.

My point here is, the pave paws situation is a great deal more complex 
than your test is capable of revealing.


AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
"If you're going to be crazy, you have to get paid for it or
else you're going to be locked up." Hunter S. Thompson

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