[time-nuts] 5370 processor boards available

Magnus Danielson magnus at rubidium.dyndns.org
Sat Mar 1 05:18:19 EST 2014

On 28/02/14 14:18, Poul-Henning Kamp wrote:
> In message <87CAF1A2-D281-4331-B019-B01B06F11DFB at rtty.us>, Bob Camp writes:
>> To me the next layer here is to see if the basic accuracy of the device
>> can be improved in software.
> I have a hard time seeing how that would happen.
> I think one of the best chances would be to improve the phase
> noise of the 200MHz signal.
> But don't miss the fact that being able to make a LOT more measurements
> in the same time also improves noise statistically.

What one possibly could do is to see if there is any round-off issues 
that causes any noise. The interpolator does not have a number-magic 
friendly gearing for decimal or binary numbers, unless you play some 
magic with it. Rounding off causes the interpolator points to be 
un-evenly distributed and by that adding a little noise to the measurement.

However, I would look at the 200 MHz systematics first. This was only to 
show what you could possibly do to improve precision in software.

With a hotter CPU you can naturally do smarter auto-triggers and 
auto-tunes and things like that.

Doing a CNT-90 like frequency estimator would indeed be possible and 
provide better frequency measures.

Frequency drift estimator would maybe be a nice addition?


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