[time-nuts] Jitter Test on Dividers

Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Sep 20 23:06:01 UTC 2009

Magnus Danielson wrote:
> John Miles wrote:
>> Interesting! 500 picoseconds is a lot of drift. Can you try 74AC390s as
>> well?
> While that may be interesting, I think we should stop here and think a
> little... where would a seemingly stable oscillation/beat frequency
> with a period of about 1250 seconds (4 cycles in 5000 seconds) come
> from? Also, it is being triangular as noted by Brian. The only thing I
> can come up with from the top of my head is power or temperature related.
> The relative quietness of the TADD-2 was nice to get confirmed. I have
> not yeat had the time to measure that with mine.
> Cheers,
> Magnus
Diurnal temperature variations convolved with A/C cycling?

Alternatively modulation of the 5V Vcc supply (150mV pp) with a 22
minute period would also produce the same effect.


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