[time-nuts] Oops - wrong URL for tvb plot!

Magnus Danielson cfmd at bredband.net
Tue Apr 10 21:11:48 EDT 2007


From: "Tom Van Baak" <tvb at LeapSecond.com>
Subject: Re: [time-nuts] Oops - wrong URL for tvb plot!
Date: Tue, 10 Apr 2007 14:26:27 -0700
Message-ID: <001401c77bb6$e6bcddb0$c1ac1cac at pc52>

Tom,

> I can see the danger now of a plot without any accompanying text.
> The raw data for the three 12 hour Motorola receivers is here:
>     http://www.leapsecond.com/pages/3gps/
> I'm on vacation right now, but I'm pretty sure these were taken
> with a 53132A against a good atomic house standard. You'll
> see a large phase offset (many microseconds), a frequency
> offset (about +3e-12 or -3e-13). No, I didn't remove frequency
> drift (if any) from the data before I plotted it.

OK. A very quick adaptation using the same program I used for the Febo
Cs1/Cs2/Rb data give these runs:

Processing vp-1pps.dat

Bias report
t =  1.608663494e-04
f =  2.770643453e-12
d = -6.750613692e-13

Deviation report
  tau         ADEV             drift          ADEV drift    ADEV drift corr      MADEV      MADEV drift corr
      1  4.496133759e-08 -6.750613692e-13  4.773404719e-13  4.496133759e-08  4.496133759e-08  4.496133759e-08
      2  2.865449852e-08 +3.636859572e-14  5.143296131e-14  2.865449852e-08  2.156096803e-08  2.156096803e-08
      5  1.023033819e-08 -3.068109484e-13  1.084740511e-12  1.023033814e-08  5.035764941e-09  5.035764883e-09
     10  5.467657422e-09 -9.345581882e-15  6.608324323e-14  5.467657422e-09  1.851770267e-09  1.851770292e-09
     20  2.739243283e-09 +1.598685109e-14  2.260882162e-13  2.739243274e-09  6.821017995e-10  6.821018772e-10
     50  1.093507243e-09 +5.205704132e-15  1.840494346e-13  1.093507227e-09  1.715728448e-10  1.715728594e-10
    100  5.454287557e-10 -6.415818074e-16  4.536668467e-14  5.454287538e-10  6.120960706e-11  6.120958759e-11
    200  2.703346601e-10 -1.108422405e-16  1.567545998e-14  2.703346596e-10  2.191194834e-11  2.191193475e-11
    500  1.093861099e-10 +2.921066096e-17  1.032752822e-14  1.093861094e-10  6.412724502e-12  6.412726902e-12
   1000  5.457886650e-11 +1.802704891e-17  1.274704853e-14  5.457886502e-11  2.565426688e-12  2.565390448e-12
   2000  2.708262717e-11 -2.666445822e-17  3.770923845e-14  2.708260091e-11  8.491241117e-13  8.457943641e-13
   5000  1.095479778e-11 -2.350726513e-17  8.311073291e-14  1.095448251e-11  2.883950982e-13  2.965846010e-13
  10000  5.449823758e-12 -2.243416118e-17  1.586334750e-13  5.447514517e-12  3.021670741e-13  1.702555808e-13
  20000  2.759576507e-12 -3.330702851e-17  4.710325145e-13  2.719079048e-12 -0.000000000e+00 -0.000000000e+00

Processing cns-1pps.dat

Bias report
t =  1.600450573e-04
f =  2.913835034e-12
d =  7.500681880e-14

Deviation report
  tau         ADEV             drift          ADEV drift    ADEV drift corr      MADEV      MADEV drift corr
      1  1.577095429e-08 +7.500681880e-14  5.303783021e-14  1.577095429e-08  1.577095429e-08  1.577095429e-08
      2  7.681160884e-09 -1.636586807e-13  2.314483259e-13  7.681160881e-09  5.415005871e-09  5.415005862e-09
      5  3.078415865e-09 +2.509775393e-14  8.873395999e-14  3.078415864e-09  1.361031473e-09  1.361031473e-09
     10  1.560186382e-09 -1.102824139e-14  7.798144274e-14  1.560186380e-09  4.738158072e-10  4.738158043e-10
     20  7.798503527e-10 -7.791528277e-15  1.101888496e-13  7.798503449e-10  1.790275974e-10  1.790276051e-10
     50  3.127308712e-10 -1.816028065e-15  6.420628798e-14  3.127308646e-10  5.422110976e-11  5.422112463e-11
    100  1.584470437e-10 +8.630531074e-17  6.102707048e-15  1.584470436e-10  2.574021466e-11  2.574020071e-11
    200  7.909625288e-11 +2.777076930e-16  3.927379858e-14  7.909624313e-11  1.050007533e-11  1.050024793e-11
    500  3.205724824e-11 +4.136006326e-17  1.462299060e-14  3.205724491e-11  3.743227983e-12  3.743161194e-12
   1000  1.592153776e-11 +8.830182390e-17  6.243881847e-14  1.592141533e-11  1.742977833e-12  1.742820380e-12
   2000  8.001780034e-12 +2.310428021e-17  3.267438643e-14  8.001713322e-12  9.412214466e-13  9.412798792e-13
   5000  3.255675022e-12 +2.633754927e-17  9.311729843e-14  3.254343101e-12  5.166966738e-13  5.179242182e-13
  10000  1.628568806e-12 -3.689307442e-18  2.608734310e-14  1.628359852e-12  2.251512130e-13  2.037213874e-13
  20000  7.937637120e-13 -4.168959480e-18  5.895799037e-14  7.915710870e-13 -0.000000000e+00 -0.000000000e+00

Processing cns2-1pps.dat

Bias report
t =  4.809698766e-06
f = -4.750323886e-13
d = -2.045640513e-14

Deviation report
  tau         ADEV             drift          ADEV drift    ADEV drift corr      MADEV      MADEV drift corr
      1  3.040349710e-09 -2.045640513e-14  1.446486278e-14  3.040349710e-09  3.040349710e-09  3.040349710e-09
      2  1.509947204e-09 +5.682593081e-15  8.036400204e-15  1.509947204e-09  1.076505673e-09  1.076505673e-09
      5  6.266960438e-10 +4.364826771e-15  1.543199304e-14  6.266960436e-10  2.869965363e-10  2.869965353e-10
     10  3.148999828e-10 +9.550229660e-16  6.753032155e-15  3.148999827e-10  1.133942495e-10  1.133942491e-10
     20  1.644818676e-10 +2.593384594e-15  3.667599666e-14  1.644818635e-10  6.136054942e-11  6.136054016e-11
     50  7.457270904e-11 +1.477060458e-15  5.222197332e-14  7.457269075e-11  3.193493744e-11  3.193493587e-11
    100  4.169473933e-11 -2.331156674e-16  1.648376692e-14  4.169473607e-11  1.940095259e-11  1.940091575e-11
    200  2.200754349e-11 -1.725996605e-16  2.440927808e-14  2.200752995e-11  9.311192242e-12  9.311282574e-12
    500  9.181425432e-12 -6.932415461e-17  2.450978991e-14  9.181392717e-12  3.417399863e-12  3.417697168e-12
   1000  4.884844476e-12 +3.584932616e-17  2.534930163e-14  4.884778702e-12  1.648103405e-12  1.648096413e-12
   2000  2.481602408e-12 +3.268600930e-17  4.622499765e-14  2.481171852e-12  8.672402194e-13  8.677237253e-13
   5000  1.226006674e-12 -3.996599800e-17  1.413011410e-13  1.217836751e-12  5.364543130e-13  5.210280149e-13
  10000  5.560201741e-13 +9.211600967e-19  6.513585509e-15  5.559820206e-13  1.500836169e-13  1.448395041e-13
  20000  2.290070692e-13 -7.158016508e-18  1.012296403e-13  2.054185914e-13 -0.000000000e+00 -0.000000000e+00

What you will notice here is that for these measures, they are short enought
not to be greatly limited by the ADEV drift line. Also notice that I calculate
this on a per tau basis, since the effective drift as it bias the ADEV and MDEV
calculation is actually calculated as an average and then removed before
further accumulation. The MDEV will actually weight certain drift-samples
higher than others, but this have not been used, but the ADEV drift estimator
was used in its place. The correction for this is however straighforward.

Also notice that the ADEV drift-line is calculated out from the drift estimator
drift(tau) by multiplying with tau divided by the square root of 2.

I also notice that our ADEVs deviate from each other. Hmm. Ah, I must look in
your overlapping column! Then they seem to match fairly closly.

I only made 1,2,5 steps, but I could to any integer multiple of tau with
trivial top-level modification.

Cheers,
Magnus




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