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

John Miles john at miles.io
Sat Nov 1 03:01:19 EDT 2014

> >It seems to me that it's just a case of expecting too much from a counter.
> Possibly, but a well-tuned 5370B can get to the low e-12's at 1-10
> seconds.  

You can get down there with TI averaging, but the data you get is not ideal since the averaging process smooths out the very instabilities you're trying to characterize. (See Tom's page at http://www.leapsecond.com/pages/adev-avg/ for a good intuitive explanation.)

> Yes, using TI mode is essential for getting down to the counter's
> limits.  Was Karen using frequency mode?  I wasn't paying attention
> to that end of things.

I'm not sure, but that's where most people start out.  Going to TI mode may improve things a bit at the cost of a more complex, error-prone measurement process, but it still isn't going to measure a Morion at t=1s.

-- john, KE5FX
Miles Design LLC

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