[ntp:questions] Re: Using a Rubidium clock with NTP

David L. Mills mills at udel.edu
Fri Oct 8 02:50:24 UTC 2004


I have an old Rubidium oscillator, too. The way to use it is find a 
battered old frequency counter with gated output and set it to count 
down to 1 PPS. Connect the gate via the PPSAPI and the atom driver, but 
do not used the kernel. Use the fudge1 parameter to adjust the phase. 

My Rubidium has a voltage input that can change the frequency slightly. 
Put a pot on that and use stereo headphones, one connected to a WWV 
reciever and the other across the gate. Adjust the pot to match the 
1-pps pip on WWV to the click from the gate. Pretend you are a human 
feedback loop, because this will be very tricky.


David Schwartz wrote:

>     Unfortunately, NTP does not support the use of an unsynchronized PPS 
> source. There are quite a few ways you could synchronize the rubidium output 
> yourself, but they all require an output with a much higher frequency than 1 
> Hz. Theoretically, NTP could be made to use the PPS input to tweak the rate 
> at which time flows.
>     DS

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