[time-nuts] A first MDEV plot...

John Miles jmiles at pop.net
Tue Mar 16 22:14:32 UTC 2010


> That won't work as one of the sources is the PPS output from an Oncore
> GT which has a PPS error spec < 500ns with SA on.
> Whilst it may be a little lower without SA, it may be still be somewhat
> greater than 100ns.
>
> Dividing the 10MHz down to 1MHz or perhaps 100kHz would be better.
> The 5370A timebase noise contribution to the measurement error will
> still be insignificant.
>
> The plot doesnt appear too discordant with the Oncore GT spec.

Ah, interesting... I stand corrected, then.  Not at all familiar with that
particular piece of hardware.  Looks like the jitter is more like 600 ns or
so (6E-7 at t=1s), so the measurement is in the right ballpark after all.

I hadn't tried TI in a 1-pps versus 1-pps measurement for some time, so I
ran a measurement overnight.  The graphs were fine but the frequency-count
chart is buggy (to put it charitably)...

-- john, KE5FX





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