[time-nuts] G3RUH GPS Stabilized Oscillator

[Richard W. Solomon]

I had thought of something similar, using a Lissajous pattern, but that
only compares one oscillator against the other.
Once I determine that the XO is indeed locked, then the next step is to
determine the frequency.
But, the first step is to determine that the XO is locked.

Then I'll go looking for that Invar rod !!

Thanks, Dick, W1KSZ

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of Pete
Sent: Saturday, January 20, 2007 4:40 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] G3RUH GPS Stabilized Oscillator


Dick,

A newer dual trace 'scope & some patience can tell you a bunch.

A 500Mhz 'scope set to 2nS/div with the 10MHz OXCO outputs on chA & chB,
triggerred on A (or B) has
a sensitivity of  2E-9/s for the traces drifting apart 1div. If you can get
both zero crossings on screen (variable delay
line helps) & they appear to be stationary & stay within 1div for 200s, you
can be pretty sure they're locked.
This should equate to 1E-11/div & the oscillators probably have more
(uncorrected) drift than that over 200s.

Pete Rawson


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