[time-nuts] Ultra low phase noise floor measurement system for RF devices.

SAIDJACK at aol.com SAIDJACK at aol.com
Sat Mar 31 19:08:22 EDT 2007


 
In a message dated 3/31/2007 04:50:11 Pacific Daylight Time,  
cfmd at bredband.net writes:

I agree,  it is indeed a fantastic number, but you have to compare it with
other  results. There is comercial tools out there which is only 20-30 dB
behind.  Actually, the correlation techniques improves the longer you average,
so  then stability of setup and such becomes the hurdles, without looking  I
would guess they have put some thought into that. Normal  crosscorrelation
techniques looks like crude conceptual setups compared to  this more elaborate
setup.

I'm looking forward to read about  this.

Cheers,
Magnus





Hi Magnus,
 
 
BTW: here in the US they also like to measure things in fractions, and body  
part lengths for some unexplainable reason... Reasons I do hear are that SI  
is too "difficult" for the average Joe to comprehend, and replacing road signs  
costs too much.
 
Gotta get my 5/32 Fluid Ounce, 3-7/16 Inch Latte now :)
__________

 
My requirements are not that high: I recently got a Wenzel Ultra Low Noise  
OCXO, have a DC-coupled Mixer, and 'just' need to build the low noise amps for  
the PLL and baseband amplification.
 
Will feed that into my Audio Precision System Two Audio  Analyzer, and see if 
I can't get close to -200dBc  (Well, I'd be happy  to measure -155 to 
-160dBc/Hz noise floor already).
 
Does anybody have any experience with using real Audio analyzers for these  
phase noise measurements?
 
I am particularly interested in how to calibrate the system, and find the  
descriptions at Wenzel lacking, and at Vectron not detailed enough...
 
bye,
Said



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