[time-nuts] RFTG-u REF 0 Z3812 as cleanup module for FEI5680A

EWKehren at aol.com EWKehren at aol.com
Tue Nov 18 09:22:03 EST 2014

I would not mess with the power management of the unit, HP did know what  
they where doing. Any clean up I would move off the unit if you want to stay  
with the same OCXO you have one in the second unit. 
As to phase noise before time nuts issues took up all my time low noise  
signal generators where my main focus and will be again. I know of no high  
quality Sig. Gen  that does not include a 100 MHz XO and in some cases  higher 
frequency SAW units. And that has been going on for as long as I can  
remember and I am 72.
One subject no one has touched on is thermal control. I do not know but  
suspect forced air cooling that would explain why all connectors on the front. 
 From comments by some members we are looking at 20 W. I will include a fan 
along  with temperature control.
Bert Kehren
In a message dated 11/18/2014 12:21:32 A.M. Eastern Standard Time,  
don_hendi at gmx.de writes:

Hello  List,

having not looked at the spectra yet as I am confined to mobile  phone 
instead of PC often, I had the idea to marry those two well-known  
devices to get a nice clean reference oscillator. I remember the  
spectrum of the FEI as not so nice, and the MTI sounds  better.

My understanding is yet that I would need to emulate the  REF1 unit, 
basically need to look up the "lonely REF" tweak with the  bridges in J5, 
maybe fake valid GPS datagrams with a microcontroller and  turn the 1PPS 
pulse from the FEI into that 2 PPSes  expected.

Replacing the Lucent Power Brick with a linear supply and  bridging the 
tripler to get 5 MHz out might be tweaks to increase the  output spectrum 
further. This was discussed before, I think, i have to  look it up too.

(I wonder if the REF0 acts up after complete removal of  the source REF1 
or keep on doing holdover which would be a nice way to  take a good 
frequency standard to a ham radio repeater  side)



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