[time-nuts] Higher measurement rate to improve TIC quality?
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Fri Apr 20 20:09:37 EDT 2007
Brooke Clarke wrote:
> Hi:
>
> I'm still trying to understand Allan plots. For example looking at a Time
> Interval Counter's stability.
>
> The one shot resolution of the Time Interval Counter is important since it
> determines the stability floor on an Allan plot. Can the stability floor be
> improved by making the measurements faster? That would move the one shot
> resolution point to the left thus moving the line down.
>
> For example if the one shot resolution of a TIC was 10 ns when measuring a 1
> PPS signal that defines a point at 1 second on the X-axis and at 10 ns on the
> Y-axis. Now if the measurement can be made 10 times in each second (the test
> signal is changed to a 10 Hz square wave), then the point on the Allan curve is
> now a facter of 10 lower.
>
> Have Fun,
>
> Brooke Clarke
>
Brooke
No, the resolution of the measurement for 1 cycle of a 10Hz square wave
is degraded to 1E-7 cf with 1E-8 for 1 cycle of a 1Hz square wave.
Bruce
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