[time-nuts] Setting Osc Frequencies

Tom Van Baak tvb at leapsecond.com
Fri Mar 2 21:40:59 EST 2007


> HI All , first time request. I wish to know how I can accurately set some 
> oscillators on frequency. I have 3 Sulzer oscillators .. 1 x 2.5A and 2 x 
> 2.5C's and 1 matching P/S with dead nicads.

> My main reference is a  Trimble Thunderbird which was the second source to 
> the HP unit was used in cellular phone installations in the US a while ago I 
> think that they maybe Nortel pulls like the HP's that were around.

> I have tried in the past by putting the main reference into input "A" and 
> triggering 1 cycle of 10 MHZ and feeding one of the other oscillators into 
> input "B" and adjusting the Sulzer to be totally overlaid with no movement 
> over many hours.. All Sulzers had been on for 36 hours before the test.and 
> the Trimble has been on for 2 years.

> What accuracy can I expect from this method, and is there a better method 
> with the equipment I have.
> Regards, Don     VK3YV....... 

It would depend on the specs of the time interval or frequency
counter you're using. You mention, 1 cycle of 10 MHz; that's
100 ns. And you mention "many hours". The upper limit based
on that alone is 100 ns over, say, 10 000 seconds which gives
you a resolution of 1e-7 / 1e4 seconds = 1 part in 10 to the 11th.

That's than enough accuracy, since, during that couple of
hours a 36-hour warmed-up Sulzer will likely have drifted in
frequency by about that amount.

/tvb




More information about the time-nuts mailing list