From: Emanuel Berg <embe8573@student.uu.se>
Subject: Re: how to analyze clock drift
Date: Thu, 20 Nov 2014 21:41:41 +0100
Date: 2014-11-20T21:41:41+01:00 [thread overview]
Message-ID: <87fvdd38qi.fsf@debian.uxu> (raw)
In-Reply-To: 188uppnlnvqgq$.1kjz3jnhjxqji.dlg@40tude.net
"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
writes:
> Yes, that is when you already know the expected
> time. I assumed that the reference clock and the
> clock used in wait are different clocks, deviating
> at constant speed.
Yes, I should have told you. The data I posted
yesterday from the Lisp program - the first trace are
the measured tick times in nanoseconds, and the
intended tick is *1 ms*.
The outputs are by doing the suggested:
offset = time1 - time2 - DESIRED_TICK
(I wonder if I made a mistake here - I assume I should
put DESIRED_TICK in nanos as well? - and I don't
remember doing that.)
Anyway if this method is good, can I make any
conclusions from the data? For example, how big a mean
would be considered a big drift, how big a deviation
an uneven drift, and so on?
Here is the original data again:
For these clock ticks (in nanoseconds):
85033108461718
85033109544537
85033110621490
85033111714366
85033112794112
85033113871903
85033114934049
85033116009605
85033117089909
85033118169656
85033119256945
85033120336411
...
The output is:
readings: 543
mean: 1076366.000000
variance: 14127140.000000
standard deviation: 3758.608785
min: 1062145
max: 1096507
1082818
1076952
1092875
1079745
1077790
1062145
1075555
1080303
1079746
1087288
1079465
1072762
...
--
underground experts united
next prev parent reply other threads:[~2014-11-20 20:41 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-18 22:12 how to analyze clock drift Emanuel Berg
2014-11-19 1:41 ` tmoran
2014-11-19 2:10 ` Emanuel Berg
2014-11-19 10:30 ` Jacob Sparre Andersen
2014-11-19 22:15 ` Emanuel Berg
2014-11-20 16:27 ` Stephen Leake
2014-11-20 1:10 ` Emanuel Berg
2014-11-20 14:11 ` Dennis Lee Bieber
2014-11-19 13:08 ` Brian Drummond
2014-11-19 2:10 ` Simon Clubley
2014-11-19 2:37 ` Emanuel Berg
2014-11-19 2:28 ` Dennis Lee Bieber
2014-11-19 2:44 ` tmoran
2014-11-19 2:51 ` Emanuel Berg
2014-11-19 9:01 ` Dmitry A. Kazakov
2014-11-19 22:12 ` Emanuel Berg
2014-11-20 9:42 ` Dmitry A. Kazakov
2014-11-20 20:41 ` Emanuel Berg [this message]
2014-11-20 21:27 ` Dmitry A. Kazakov
2014-11-20 21:54 ` Emanuel Berg
2014-11-20 21:57 ` Emanuel Berg
2014-11-21 2:27 ` Dennis Lee Bieber
2014-11-21 3:02 ` Emanuel Berg
2014-11-21 16:49 ` Dennis Lee Bieber
2014-11-21 21:06 ` Emanuel Berg
2014-11-22 18:18 ` Dennis Lee Bieber
2014-11-23 20:15 ` Emanuel Berg
2014-11-24 1:15 ` Dennis Lee Bieber
2014-11-24 1:34 ` Emanuel Berg
2014-11-24 9:22 ` Jacob Sparre Andersen
2014-11-24 17:30 ` Dennis Lee Bieber
2014-11-24 8:44 ` Dmitry A. Kazakov
2014-11-24 17:24 ` Dennis Lee Bieber
2014-11-24 18:28 ` Dmitry A. Kazakov
2014-11-24 20:30 ` brbarkstrom
2014-11-24 21:03 ` Dmitry A. Kazakov
2014-11-24 21:34 ` brbarkstrom
2014-11-25 14:04 ` brbarkstrom
2014-11-25 18:16 ` Dennis Lee Bieber
2014-11-25 20:50 ` brbarkstrom
2014-11-21 21:15 ` Emanuel Berg
2014-11-21 22:31 ` Emanuel Berg
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