Hi How many hours / days/ months / years had the OCXO been off power before the run was started?
How soon after turn on did you start taking data? Bob > On Oct 25, 2014, at 12:35 PM, Tom Van Baak <[email protected]> wrote: > > Let's take a real example. > > Use your own phase data, or grab any of my large data sets > (http://leapsecond.com/pages/gpsdo-sim) like ocxo.dat.gz which is a good > example of real-life OCXO performance (400,000 seconds of data). > > Attached are Stable32 plots of frequency, ADEV/MDEV, and dynamic ADEV. As a > 3D plot, the latter shows how ADEV(tau) varies during the run. In this case > the full data set is broken into about 90 pieces and ADEV is computed for > each segment of data ("window"). If you study the frequency plot you may be > able to convince yourself why the DADEV plot looks like it does; ADEV(small > tau) is quite constant, while ADEV(larger tau) varies quite a bit. To me, > this is as it should be, given how the raw data looks. > > To explore dynamic ADEV without Stable32 or to go deep with the effects of > sample size, see adev6.c / adev6.exe in my tools directory > (www.leapsecond.com/tools). > > Most programs compute ADEV based on the entire data set. But adev6 will > compute ADEV(tau) in user defined subsets of data. So, for example, instead > of computing ADEV(tau 1) from 400,000 points, you can compute ADEV(tau 1) 400 > times in blocks of 1000 points each, or 4000 times in blocks of 100 points > each, etc. The default is back-to-back segments but you can specify > overlapping segments. Using various combination of parameters, it's pretty > instructive to see the "noise" in computed value of ADEV. > > The 4th attachment is a TimeLab plot of the data set with trace = 1 > (default), 10, and 100. In some cases I prefer this sort of display. One can > get complacent with simple error bars and forget that 1 - 68% = 32% of the > points must always lie outside the error bars, by definition. > > /tvb<ocxo-freq-1.gif><ocxo-amdev-1.gif><ocxo-dadev-1.gif><ocxo-trace-1-10-100.gif>_______________________________________________ > 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. _______________________________________________ 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.
