Hi Scott. Here is a textfile with data for the 10 years (As in the graph 2001-2011).
Also the ln(bt+1) fit, as Magnus said, has the derivate b/(b*t+1) that with b*t >>1 is 1/t. But my data has the aging between 1 and 10 years more like 1/sqrt(t) If I just have a brief look on the aging graph. Lars Från: Scott Stobbe<mailto:[email protected]> Skickat: den 19 november 2016 04:11 Hi Lars, I agree with you, that if there is data out there, it isn't easy to find, many thanks for sharing! Fitting to the full model had limited improvements, the b coefficient was quite large making it essentially equal to the ln(x) function you fitted in excel. It is attached as "Lars_FitToMil55310.png". So on further thought, the B term can't model a device aging even faster than it should shortly after infancy. In the two extreme cases either B is large and (Bt)>>1 so the be B term ends up just being an additive bias, or B is small, and ln(x) is linearized (or slowed down) during the first bit of time. You can approximated the MIL 55310 between two points in time as f(t2) - f(t1) = Aln(t2/t1) A = ( f(t2) - f(t1) )/ln(t2/t1) Looking at some of your plots it looks like between the end of year 1 and year 10 you age from 20 ppb to 65 ppb, A ~ 20 The next plot "Lars_ForceAcoef", is a fit with the A coefficient forced to be 2 and 20. The 20 doesn't end-up fitting well on this time scale. Looking at the data a little more, I wondered if the first 10 day are going through some behavior that isn't representative of long-term aging, like warm-up, retrace (I'm sure bob could name half a dozen more examples). So the next two plots are fits of the 4 data points after day10, and seem to fit well, "Lars_FitAfterDay10.png", "Lars_1Year.png". If you are willing to share the next month, we can add that to the fit. Cheers, On Fri, Nov 18, 2016 at 1:26 PM, Lars Walenius <[email protected]> wrote: > > Hopefully someone can find the correct a and b for a*ln(bt+1) with stable32 or matlab for this data set: > Days ppb > 2 2 > 4 3.5 > 7 4.65 > 8 5.05 > 9 5.22 > 12 6.11 > 13 6.19 > 25 7.26 > 32 7.92
days ppb 2 2 4 3.5 7 4.65 8 5.05 9 5.22 12 6.11 13 6.19 25 7.26 32 7.92 33 8.15 39 8.42 46 8.92 46 9.18 47 9.02 54 9.51 60 9.78 74 10.45 83 11.36 92 11.78 97 12.08 110 12.8 128 13.6 158 14.7 193 15.9 224 16.9 254 18 284 19.01 314 20 343 21.1 375 22.3 417 23.7 445 24.8 476 25.7 515 26.7 545 27.7 586 28.8 615 29.4 646 30.2 672 30.7 703 31.4 743 32.2 787 33.5 826 34.6 861 35.3 904 36.2 940 37 976 37.7 1010 38.5 1046 39.1 1072 39.5 1081 38.3 1124 38.6 1163 39.6 1201 40.5 1239 41.2 1285 42.2 1320 43 1357 43.6 1398 44.4 1432 45 1467 45.7 1501 46.3 1534 47.1 1560 47.7 1597 48.4 1628 48.9 1659 49.3 1687 49.9 1718 50.35 1748 50.7 1779 51.2 1809 51.5 1850 52 1886 52.6 1914 53 1947 53.45 1984 53.9 2019 54.3 2045 54.5 2071 54.7 2116 55.11 2132 54.97 2165 55.27 2198 55.63 2230 56 2265 56.5 2309 57 2346 57.4 2389 57.85 2434 58.35 2473 58.7 2513 59 2550 59.3 2587 59.65 2625 60 2664 60.35 2696 60.6 2729 60.85 2764 61.15 2796 61.4 2829 61.6 2863 61.85 2898 62.1 2935 62.4 2972 62.8 3007 63.12 3043 63.47 3078 63.73 3114 64.05 3149 64.3 3184 64.5 3224 64.75 3259 64.96 3295 65.23 3332 65.54 3368 65.82 3406 66.09 3441 66.33 3482 66.55 3519 66.72 3563 67.01 3604 67.22 3647 67.59 3692 68.02
_______________________________________________ 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.
