[time-nuts] The 5MHz Sweet Spot

EWKehren at aol.com EWKehren at aol.com
Sun Nov 3 17:51:30 EST 2013


We are looking at room temperature 5 and 10 MHz XO's for cleaning up Rb and 
 DDS. Filter time 1 to 20 seconds and thermal mass to keep temperature 
influence  low. Hard to find XO's, so what we are testing is older TCXO's where 
we remove  the TC and use the tuning circuit for loop control. Any 
suggestions? Maybe  slightly off subject but the experts are here.
Thanks  Bert Kehren
 
 
In a message dated 11/3/2013 4:41:43 P.M. Eastern Standard Time,  
saidjack at aol.com writes:

The  partial answer is: yes as they typically use 10MHz crystals too. But 
the loop  BW is so wide (10Hz or more) that the crystal jumps get compensated 
very  quickly.

We have not seen any real frequency jumps in 100's of CSACs we  tested that 
use vapor cells just like RB's do, so from my experience I have  never seen 
a discrete frequency jump in an Atomic oscillator..

Notice  that CSACs do jump significantly in frequency right after power on 
when they  achieve atomic lock, typically about 60s after power on.

Vapor cell  atomic clocks typically have other issues such as excessive 
retrace, loss of  vacuum and a subsequent slow drift in frequency, and almost 
instantaneous loss  of atomic lock causing frequency jumps when operated 
above max  temperature..

Sent From iPhone

On Nov 3, 2013, at 13:28, Hal  Murray <hmurray at megapathdsl.net> wrote:

> 
> Do low cost  recycled Rubidiums have any quirks equivalent to frequency 
jumps 
> in  crystals?
> 
> 
> 
> -- 
> These are my  opinions.  I hate spam.
> 
> 
> 
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