[time-nuts] GPS: ADEV or MDEV?
phk at phk.freebsd.dk
Tue Apr 10 01:25:56 EDT 2007
In message <004e01c77b09$d095aa60$6500a8c0 at EBS8500>, "Brooks Shera" writes:
>The impact of time averaging to suppress white phase noise is illustrated
>by a new plot TVB has created and placed on his website
>These revealing plots show that just a few hundred-second time average has
>largely removed the performance
>difference between the aged VP and the newer M12+ and has almost entirely
>removed the benefit of sawtooth correction (CNS-CNS II). These important
>results are not evident in the usual ADEV plot.
This is simply not true. No averaging period can ever guarantee you
will not get a constant offset from the sawtooth. You may get rid
of the noise, but not the bias.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
More information about the time-nuts