-------- In message <[email protected]>, Bob Camp writes:
> The approach you are using is still a discrete time sampling > approach. As such it does not directly violate the data requirements > for ADEV or MADEV. As long as the sample burst is much shorter > than the Tau you are after, this will be true. If the samples cover < 1% > of the Tau, it is very hard to demonstrate a noise spectrum that > this process messes up. So this is where it gets interesting, because I suspect that your 1% "lets play it safe" threshold is overly pessimistic. I agree that there are other error processes than white PM which would get messed up by this and that general low-pass filtering would be much more suspect. But what bothers me is that as far as I can tell from real-life measurements, as long as the dominant noise process is white PM, even 99% Tau averaging gives me the right result. I have tried to find a way to plug this into the MVAR definition based on phase samples (Wikipedia's first formula under "Definition") and as far as I can tell, it comes out the same in the end, provided I assume only white PM noise. But I have not found any references to this "optimization" anywhere and either I'm doing something wrong, or I'm doing something else wrong. I'd like to know which it is :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [email protected] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
