[time-nuts] WWV receivers?

[Attila Kinali]

On Fri, 28 Oct 2016 23:01:52 -0700
Hal Murray <hmurray at megapathdsl.net> wrote:

> nsayer at kfu.com said:
> > That single-chip version is going to have a *LOT* less (and less variable)
> > latency than an SDR. 
> 
> Latency isn't an issue as long as it is known so that you can correct for it.
> 
> Has anybody measured the jitter through SDR and/or tried to reduce it?  I'd 
> expect that even if you counted cycles and such there would still be jitter 
> from not being able to reproduce cache misses and interrupts.

Should not be too high. If Jeff Sherman's and Robert Jörden's paper[1]
is any indication, then the jitter should be dominated by the jitter
of the ADC and its reference oscillator. So sub-ps, order of 100fs jitter
should be possible with proper design. Long term drift is another issue
and I have not completely figured out what are the contributors there.
Temperature stabilizing for sure helps, but it doesn't seem to be the
only effect.


			Attila Kinali

[1] "Oscillator metrology with software defined radio",
by Jeff Sherman and Robert Jörden, 2016
http://dx.doi.org/10.1063/1.4950898
http://arxiv.org/abs/1605.03505


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