[time-nuts] Frequency counter questions
kb8tq at n1k.org
Wed Apr 26 07:32:31 EDT 2017
> On Apr 26, 2017, at 2:31 AM, Mark Sims <holrum at hotmail.com> wrote:
> If your frequencies of interest can be divided down to to the 1PPS range, the TAPR TICC makes for an excellent frequency counter. The TADD-2 Mini divider handles 1/2.5/5/10 Mhz or with a PIC chip swap 1/5/10/15 MHz. The TICC has around 100 ps of jitter so you can get 1E-10 resolution at 1 second... the TICC noise floor at 1000 seconds is less than 1E-13.
> I used the TICC to adjust my 5065A and FTS-4060 cesium C-fields. Referenced to a 5071A, the results are better than 0.00002 Hz (the spec'd limit of the devices).
> Attached is a plot of the FTS-4060 using a 5071A as the reference. Over a 1000 second interval the average frequency is off 0.000002 Hz.
This gets one off into the area of “how do I build a 9/10/11/12 digit a second counter?”. As everybody has guessed by now,
that’s the project I would do rather than a straight counter. TICC, F7, a dirt cheap FPGA card ….
> Ignore the yellow debug output in the plot... I'm currently working on how to scale and plot the new MTIE (Maximum Time Interval Error) data that Heather can now calculate.<ticc.gif>_______________________________________________
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