[time-nuts] Re: GPS receiver with reference clock input

[Keelan Lightfoot]

HÃ¥kan,

I think what is plotted is microseconds, not nanoseconds.  Since it
> looks like it wraps at 1000000.
>
> If so, the blue curve is just a free-drifting clock?
> (4 second total drift)
>

The axes are labeled on either side, 'nanoseconds' and 'Sigma
(nanoseconds)'. The blue curve is a free drifting clock.... Ohhh,  I just
realized that a scale value is also printed on the graph, so my "good"
clock is actually terrible because the scale is 1e8.

Digging through the data a bit more, the summary file lists the drift...

"good": -464001302.4506 ns/day (not good at all, looks like the calibration
on my counter is terrible)

"bad": 234484.6468 ns/day

I have a third:

http://beefchicken.com/dump/clockoffsetugly.png

for that dataset, the drift is 1661643.4279 ns/day

- Keelan