[time-nuts] The 5MHz Sweet Spot
Said Jackson
saidjack at aol.com
Mon Nov 4 02:52:16 UTC 2013
Bert,
Let me know if you can do stable >1s loops in the analog domain with reasonable cap sizes say <220uF. I would be impressed. I tried.
Bye,
Said
Sent From iPhone
On Nov 3, 2013, at 14:51, EWKehren at aol.com wrote:
> 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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