[time-nuts] COMPARE GPS DERIVED 10MHz FREQUENCY OF TO LOCAL OSCILLATOR

John Ackermann N8UR jra at febo.com
Wed Nov 8 18:00:33 EST 2006


jshank said the following on 11/08/2006 05:12 PM:

> What would be a good method of using my Z3801A 10MHz out put to adjust the oscillator adjustment dial on my 8130 Spectracom Frequency Standard Oscillator.  When I use the 8160A Spectracom NSB frequency Standard Receiver WWVB it has a frequency calibration feature which allows a local oscillator to be compared to the wwvb signal showing phase drift or slight frequency error in microseconds as well as a frequency counter showing frequency difference in 0.01 Hz and a recorder output allowing for monitoring to occur of several days.  
> 
>  
> 
> My question is what instrumentation or methods can I use to set my local oscillator to the Z3801A gps signal.  I know there is instrumentation such as Tracor 527E Frequency Difference Meter which may provide some of the features as the Spectracom 8160A, but is this what I am look for.

Hi Jeff --

A lot depends on how much accuracy you want.

One simple method is to use the Z3801A as the frequency reference
driving a frequency counter, and then just measure the frequency of the
Spectracom.  Depending on the counter, you can get from 1Hz to better
than 0.001Hz accuracy.

Another way is to use an oscilloscope to watch the drift of the Z3801A
versus the Spectracom.  You can set the scope up to show a Lissajous
display, or just use one signal to trigger the scope while viewing the
other.  Either way will let you calculate the frequency offset by
measuring how quickly the Spectracom signal drifts some amount (e.g., 1
cycle) away from the reference.

Hope this helps!

John




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