| Re: [chrony-dev] Frequency synchronization without phase |
[ Thread Index |
Date Index
| More chrony.tuxfamily.org/chrony-dev Archives
]
On Wed, Dec 28, 2016 at 05:57:15PM -0600, Dan Drown wrote:
> That looks like this (green=Linux system's clock, purple=TCXO's measurement
> of Linux system's clock).
> https://dan.drown.org/odroid/run7/tcxo-acc-1024.png
>
> I've adjusted the starting offset to be within 50ppb, but the TCXO drifts
> off and the difference widens to over 300ppb after 3 days.
Would a high-pass filter help?
> Here's how tempcomp.log vs tracking.log looks:
> https://dan.drown.org/odroid/latest/tempcomp.png
This looks awesome :).
> Unrelated to tempcomp, I'm also trying out the new asymmetry code because
> I'm on a recent git version. I assume the offset value in statistics.log is
> corrected for asymmetry while the offset value in measurements.log is not.
Yes.
> I've added the two offsets to my graphs:
> https://dan.drown.org/odroid/run9/remote-statistics.96.126.122.39.png
> https://dan.drown.org/odroid/run9/remote-statistics.216.239.35.0.png
> https://dan.drown.org/odroid/run9/remote-statistics.216.239.35.4.png
This looks pretty good to me. At this moment it nicely shows how
updating the minimum measured delay shifts the offset line.
The graphs don't show it anymore, but IIRC when I looked at it the
first time one of the sources had the statistics offset overlapping
the bottom offset-rtt/2 line and I was not sure how would that happen.
It looked like the minimum measured delay was zero or maybe even
negative, or it was shifted by the offset option. If you still have
the old data, I'd be interested to see a separate graph of the delay.
--
Miroslav Lichvar
--
To unsubscribe email chrony-dev-request@xxxxxxxxxxxxxxxxxxxx with "unsubscribe" in the subject.
For help email chrony-dev-request@xxxxxxxxxxxxxxxxxxxx with "help" in the subject.
Trouble? Email listmaster@xxxxxxxxxxxxxxxxxxxx.