[time-nuts] Question on crystal jumps

SAIDJACK at aol.com SAIDJACK at aol.com
Fri Oct 24 08:33:43 UTC 2008


Hello Neville,
 
interesting info! Yes, chemical processing apparently can "fix" jumpy  
crystals. Wish we had more crystal processing experts post their experience  here.
 
It is interesting to note that some of these jumps on the order of say 0.1  
parts per billion or less are probably caused by only a couple of molecules  
reaching or leaving the crystal.
 
In a GPSDO, a very small change of only 0.1ppb will cause a massive change  
in phase of 50ns within 8 minutes.
 
On our Fury/FireFly GPSDO such a phase error would be arrested very quickly  
to prevent it from getting worse, and then the servo loops would push-back 
this  phase offset to 0ns over an hour or so to minimize the frequency error.
 
bye,
Said
 
 
In a message dated 10/23/2008 22:33:23 Pacific Daylight Time,  
namichie at gmail.com writes:

Does  chemical etching reduce the frequency of micro-jumps?
Can quartz crystals  be thermally annealed?
What is interesting is the ageing mechanisms. Does  gross thermal  
cycling reduce ageing?
just some  thoughts,
Neville  mIchie





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