[time-nuts] Orbiting crystals

SAIDJACK at aol.com SAIDJACK at aol.com
Sat Jun 27 00:46:30 EDT 2009


Hi Antonio,
 
not an expert on space qualified crystals, but I would think that in  
general Cesium and Rubidium crystals would be steered very quickly (within  
seconds?) to correct for any crystal jumps that surely will happen even, or  
especially in space.
 
In a GPSDO, we generally only have one correction pulse per second from the 
 GPS, and that one is even noisy and needs to be filtered. In an atomic 
clock, we  can steer the crystal without this 1Hz limit.
 
A good gps receiver will use over-determination and not use a single sat to 
 generate the 1PPS. And even then a GPS 1PPS is expected to be noisy.
 
Bye,
Said
 
 
In a message dated 6/26/2009 16:26:22 Pacific Daylight Time,  
iovane at inwind.it writes:


this  post wouldn't be merely speculative, I have an actual 
interest in knowing  if what I'm going to ask is possible.
As it has already been discussed  here, crystals may jump in 
frequency. If I recall, about 20% of good  quality crystals are
prone to jumping, but a crystal that used to jump  might not 
jump anymore, a crystal that never jumped might jump in the  
future, and so on.




More information about the time-nuts mailing list