[time-nuts] GPS ADEV?

Tom Van Baak tvb at LeapSecond.com
Sat Apr 7 07:08:25 EDT 2007


> Tom
> 
> Is there anyway that you can derive the same plot for an M12+ receiver 
> with post facto (software) sawtooth correction?
> It should be marginally better than a CNS II. Hardware correction always 
> adds some noise. Some of the Dallas programmable delay chips used in the 
> CNS II are noisier than others.

Bruce,

Yes, that would be a good one to add to the plot. It should
reduce the jitter by 1 or 2 ns and so I suspect the software
corrected sawtooth line would be a few pixels below the
hardware corrected line on my plot.

Tom Clark & Rick Hambly showed a similar test at PTTI 2006:

Improving the Performance of Low Cost GPS Timing Receivers
ftp://ftp.cnssys.com/pub/PTTI/PTTI_2006.pdf

You'll see the nice plot comparing h/w and s/w on page 15.
They also did a linearity test. Good paper; read it all.

/tvb





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