Hi Magnus -- Any possibility that there is some math package subroutine error of some kind? In yours or theirs?
Best, Dick Moore > > Message: 3 > Date: Mon, 18 Jan 2010 03:29:49 +0100 > From: Magnus Danielson <[email protected]> > Subject: [time-nuts] Modified Total Deviation calculation > To: Discussion of precise time and frequency measurement > <[email protected]> > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Dear fellow time-nuts, > > In my effort to implement the suite of ADEV and friends, I have been > implementing various forms of them along with the 1000 frequency sample > test sequence out of NIST SP1065: > http://tf.nist.gov/timefreq/general/pdf/2220.pdf > > However, I seem to be unable to perfectly match the numbers for the MTotDev. > > My numbers so far: > > m = 1 m = 10 m = 100 > Max 0.9957452943 0.7003371204 0.5489367785 > Min 0.0013717599 0.2545924150 0.4533354120 > Avg 0.4897744629 0.4897744629 0.4897744629 > Sdev 0.2884663647 0.0929635201 0.0320665644 > NAdev 0.2922318781 0.0996573606 0.0389780433 > OSAdev 0.2922318781 0.0915995342 0.0324134303 > OAdev 0.2922318781 0.0915995342 0.0324134303 > MAdev 0.2922318781 0.0617237638 0.0217092091 > Tdev 0.1687201535 0.3563623166 1.2533817739 > Hdev 0.2943883291 0.1052754194 0.0391086056 > OHdev 0.2943883291 0.0958108317 0.0323763825 > MHdev 0.2942275231 0.0621023549 0.0213087110 > TOTdev 0.2922318781 0.0913474326 0.0340653025 > MTOTdev 0.2303857898 0.0555288598 0.0195467513 > > The MTOTdev numbers according to page 118 (of PDF, page number 108 > according to the printed pagenumbers) should be > > Modified Total Dev 2.418528e-01 6.499161e-02 2.287774e-02 > > Do anyone happend to have an implementation (in source) of MTOTdev at > hand giving the NIST SP1065 numbers? > > Please note that W. Riley has about the same document in his Handbook, > and it reflects the same number. I would also suspect that a STABLE32 > run would give those numbers. > > I have been using both SP1065 and the original article as reference: > http://tf.nist.gov/general/pdf/1369.pdf > > I've put care into ensuring that I implement it as close to these as > possible, but with no luck in fixing the numbers. > > I use the averaging of the two half-ranges of the 3*m block tecnique > rather than the minimum square estimator as recommended. The formulation > given may seem strange, but it is the 3/2*m sample average of the > > f(i)=(x[n+3/2*m+i)-x[n+i])/ (3/2*m) > > frequency estimation where i varies from 0 to 3/2*m-1. > > I have already verified my test-sequence and the numbers produced by the > other algorithms have been able to match after removing various bugs. An > independent implementation may be a good clue. > > An alternative may be that the published numbers is incorrect for some > reason, but I don't have sufficient proof for that. > > I have however made two different implementation variants that crunch > out the same numbers. > > Cheers, > Magnus _______________________________________________ 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.
