[time-nuts] 10MHz Rubidium reference source for frequency counter

Charles Steinmetz csteinmetz at yandex.com
Sun Nov 2 15:19:02 EST 2014

Karen wrote:

>Mode has been switch from Frequency to TI - result is much better 
>now. It was the main improvement in my measurement.

Your plot shows all traces starting at ~1e-9 at 0.1 second and 
dropping almost ruler-straight at 10x per decade.

Any real crystal oscillator will flatten out somewhere between 1 
second and 100 seconds, typically first to ~square root of 10 per 
decade, then to 0 per decade, and generally will be on the way back 
up before 1000 seconds and before getting to 1e-13.  (For examples, 
see <http://leapsecond.com/pages/z3801a-osc/>.)

Also, the fact that there is so little difference between the test 
oscillators is too unusual to be a coincidence.

It does not appear that you are actually measuring the ADEV of the 
oscillators you are testing -- you seem to be measuring your test setup.

Best regards,


More information about the time-nuts mailing list