[ntp:questions] What level of timesynch error is typical onWinXP?

Dave Hart davehart_gmail_exchange_tee at davehart.net
Sun Nov 7 20:21:27 UTC 2010


I regret to report ntpd 4.2.7p79, with the freq_mode fix, is still
unable to estimate the frequency on the FreeBSD 6.4 test machine.  I
repeated yesterday's tests after updating ntpd, still using the daemon
loop and four sources with iburst and maxpoll 6.

55507 47027.172 0.000131624 80.505 0.000295904 0.003852 6

This is the last loopstats line from 4.2.7p78, after it had settled
from yesterday's tests, showing the accurate frequency.

55507 47305.668 0.116321337 0.000 0.041125803 0.000000 6
55507 47309.670 0.102448652 0.000 0.038469785 0.000000 6
55507 47309.670 0.102448652 0.000 0.035985748 0.000000 6
55507 47366.669 0.016771582 0.000 0.034228017 0.000000 6
55507 47431.669 0.002129784 0.000 0.033512148 0.000000 6
55507 47432.668 0.002063228 0.000 0.033151910 0.000000 6
55507 47499.668 0.000245885 0.000 0.033268284 0.000000 6
55507 47568.668 0.000027500 0.000 0.032732507 0.000000 6
55507 47634.669 0.091580060 278.349 0.031843464 0.000000 6
55507 47700.669 0.087433242 278.349 0.029822893 0.000000 6
55507 47710.669 0.066283980 278.349 0.028881495 0.000000 6
55507 47769.669 0.052348797 278.349 0.027461734 0.000000 6
55507 47779.669 0.038045135 278.349 0.026181154 0.000000 6
55507 47836.669 0.024174098 278.349 0.024976427 0.000000 6
55507 47845.669 0.009864700 278.349 0.023904791 0.000000 6
55507 47905.669 -0.001928639 278.349 0.022746308 0.000000 6
55507 47913.669 -0.012783326 278.349 0.021620551 0.000000 6
55507 47973.668 -0.014912826 278.295 0.020238183 0.018856 6
55507 48249.669 -0.023350333 277.911 0.019164681 0.136952 6
55507 48379.669 -0.044163258 277.569 0.019378379 0.176208 6
55507 48446.668 -0.063716048 277.314 0.019400266 0.187780 6
55507 48518.669 -0.083934245 276.954 0.019504384 0.216961 6
55507 48655.668 -0.100637719 276.132 0.019176655 0.354409 6
55507 48841.669 -0.122561216 274.774 0.019541138 0.583684 6
55507 49251.501 0.000000000 274.774 0.000001907 0.545987 6
55507 49258.500 -0.019540127 274.766 0.006908478 0.510732 6
55507 49467.500 -0.021120483 274.502 0.006486400 0.486718 6
55507 49600.500 -0.053164975 274.081 0.012851863 0.479047 6
55507 49804.501 -0.072454909 273.200 0.013821606 0.545730 6

With the clock behind 116ms at start, the frequency estimate is over
3x too large.

55507 50047.438 -0.082944166 0.000 0.029325191 0.000000 6
55507 50051.440 -0.073052100 0.000 0.027432067 0.000000 6
55507 50107.437 -0.012344934 0.000 0.026044324 0.000000 6
55507 50175.438 -0.001425232 0.000 0.027895116 0.000000 6
55507 50242.438 -0.000169852 0.000 0.031936190 0.000000 6
55507 50246.438 -0.000149595 0.000 0.035742971 0.000000 6
55507 50310.438 -0.000019610 0.000 0.039331450 0.000000 6
55507 50376.438 -0.018851467 -57.292 0.043209685 0.000000 6
55507 50442.437 -0.007240184 -57.292 0.040626900 0.000000 6
55507 50447.437 -0.000713438 -57.292 0.038072978 0.000000 6
55507 50451.438 0.005444657 -57.292 0.035680499 0.000000 6
55507 50508.438 0.012774922 -57.292 0.033476519 0.000000 6
55507 50518.439 0.014070419 -57.292 0.031317766 0.000000 6
55507 50576.438 0.012945667 -57.292 0.029297786 0.000000 6
55507 50587.438 0.009913733 -57.292 0.027426526 0.000000 6
55507 50649.438 0.007395785 -57.292 0.025670607 0.000000 6
55507 50978.438 0.008587284 -57.124 0.024016348 0.059537 6
55507 51124.438 0.043736839 -56.743 0.025673396 0.145635 6
55507 51520.438 0.089396351 -54.633 0.028936685 0.758356 6
55507 51665.438 0.088605633 -53.867 0.027069234 0.759289 6
55507 51933.438 0.112923072 -52.063 0.026740750 0.954559 6
55507 52052.438 0.124493376 -51.180 0.025345971 0.945914 6
55507 52118.438 0.127715005 -50.678 0.023736330 0.902475 6
55507 52657.576 0.000000000 -50.678 0.000001907 0.844188 6
55507 52664.576 0.016489190 -50.671 0.005829809 0.789670 6
55507 52668.576 0.016691785 -50.667 0.005453758 0.738670 6
55507 53067.576 0.026779525 -50.030 0.006224617 0.726726 6
55507 53471.576 0.083394573 -48.022 0.020846117 0.982957 6
55507 53832.576 0.110887775 -45.636 0.021788185 1.247820 6
55507 54012.576 0.121168212 -44.336 0.020702544 1.254461 6
55507 54077.577 0.125136632 -43.851 0.019416216 1.185893 6
55507 54552.717 0.000000000 -43.851 0.000001907 1.109302 6

Clock started 83ms ahead of reality, frequency estimate has the wrong sign.

55507 55620.805 0.001022653 0.000 0.000361567 0.000000 6
55507 55624.805 0.000900690 0.000 0.000344022 0.000000 6
55507 55624.805 0.000900690 0.000 0.000331328 0.000000 6
55507 55680.806 0.000152206 0.000 0.000635788 0.000000 6
55507 55748.805 0.000017572 0.000 0.001913772 0.000000 6
55507 55749.805 0.000017023 0.000 0.002925621 0.000000 6
55507 55816.805 0.000002029 0.000 0.004627915 0.000000 6
55507 55820.805 0.000001787 0.000 0.006756535 0.000000 6
55507 55887.805 0.000000213 0.000 0.009488173 0.000000 6
55507 55953.805 0.025053023 75.234 0.012286357 0.000000 6
55507 56014.806 0.020799313 75.234 0.011590816 0.000000 6
55507 56080.806 0.003262439 75.234 0.012489851 0.000000 6
55507 56085.805 -0.002976502 75.234 0.011889591 0.000000 6
55507 56284.806 -0.005790262 75.166 0.011166097 0.024282 6
55507 56486.805 -0.004832251 75.107 0.010450418 0.030644 6
55507 56619.806 -0.001653216 75.094 0.009839874 0.029037 6
55507 57107.805 0.001371581 75.134 0.009266278 0.030606 6
55507 57294.806 0.002566599 75.163 0.008678100 0.030363 6
55507 57565.806 0.003550332 75.220 0.008125067 0.034897 6
55507 57771.806 0.004306454 75.273 0.007605004 0.037617 6
55507 58259.806 0.004533934 75.405 0.007114285 0.058414 6
55507 58793.805 0.005079226 75.567 0.006657596 0.079074 6
55507 58851.806 0.005470119 75.585 0.006229144 0.074268 6
55507 59187.806 0.006022272 75.706 0.005830100 0.081514 6
55507 59256.805 0.006003279 75.731 0.005453563 0.076748 6
55507 59391.805 0.005970118 75.779 0.005101355 0.073773 6
55507 59919.805 0.006141090 75.972 0.004772263 0.097114 6
55507 60309.805 0.006432901 76.122 0.004465236 0.105107 6
55507 60441.805 0.006557244 76.173 0.004177077 0.099996 6
55507 60635.805 0.006560367 76.249 0.003907298 0.097307 6
55507 60714.806 0.006276305 76.279 0.003656322 0.091620 6
55507 61240.806 0.004699083 76.426 0.003465336 0.100290 6
55507 61424.806 0.004688040 76.477 0.003241528 0.095558 6
55507 61566.805 0.004881127 76.519 0.003032940 0.090572 6
55507 62028.806 0.005194546 76.662 0.002839219 0.098669 6
55507 62146.805 0.005274662 76.699 0.002655997 0.093223 6
55507 62608.806 0.005172885 76.841 0.002484718 0.100701 6
55507 62937.806 0.004712989 76.934 0.002329922 0.099704 6
55507 63331.806 0.004662792 77.043 0.002179514 0.100980 6
55507 63397.805 0.004648114 77.061 0.002038756 0.094680 6
55507 63722.806 0.004832430 77.155 0.001908194 0.094547 6
55507 64246.805 0.004666484 77.301 0.001785916 0.102357 6
55507 64701.806 0.004691766 77.428 0.001670596 0.105788 6
55507 64768.805 0.004609847 77.446 0.001562968 0.099170 6
55507 65165.806 0.004017867 77.542 0.001476927 0.098667 6
55507 65548.806 0.003799573 77.628 0.001383693 0.097256 6
55507 65808.805 0.003839284 77.688 0.001294402 0.093375 6
55507 65893.805 0.003827564 77.707 0.001210810 0.087613 6
55507 66411.805 0.003819743 77.825 0.001132612 0.091952 6
55507 66611.806 0.003747307 77.870 0.001059771 0.087451 6
55507 66942.806 0.003664775 77.942 0.000991754 0.085704 6
55507 67268.805 0.003395993 78.008 0.000932556 0.083495 6
55507 67796.805 0.003322722 78.113 0.000872711 0.086411 6
55507 68061.806 0.003407083 78.166 0.000816891 0.083039 6
55507 68593.805 0.003187342 78.268 0.000768071 0.085501 6
55507 68989.805 0.003164909 78.342 0.000718508 0.084227 6
55507 69255.805 0.003198491 78.393 0.000672208 0.080801 6
55507 69428.805 0.003139896 78.425 0.000629134 0.076445 6
55507 69779.806 0.002965214 78.487 0.000591733 0.074796 6
55507 69976.806 0.002849590 78.521 0.000555023 0.070958 6
55507 70397.805 0.002597799 78.586 0.000526753 0.070263 6
55507 70501.806 0.002577416 78.602 0.000492785 0.065967 6
55507 70632.806 0.002619503 78.622 0.000461198 0.062129 6
55507 70941.809 0.002597823 78.670 0.000431480 0.060528 6
55507 71223.806 0.002607564 78.714 0.000403627 0.058701 6
55507 71471.806 0.002375362 78.749 0.000386381 0.056296 6
55507 71929.805 0.002268382 78.811 0.000363400 0.057030 6
55507 71941.805 0.002310620 78.813 0.000340257 0.053349 6
55507 72472.805 0.002392774 78.889 0.000319604 0.056633 6
55507 72668.805 0.002407426 78.917 0.000299007 0.053901 6
55507 72994.806 0.002265679 78.961 0.000284150 0.052767 6

With the clock off by 1ms at start, the frequency estimate is about 5 PPM low.

Happy hunting,
Dave Hart

On Sun, Nov 7, 2010 at 00:58 UTC, David L. Mills <mills at udel.edu> wrote:
> Dave,
>
> I think I have hunted down what is going on. It takes some serious
> investigation. Turns out the modern adjtime(), at least in some systems, is
> far from what I knew some years back. I have already described that era from
> what I knew of SunOS, Ultrix, OSF/1 and Tru64, since I or my graduate
> assistant  implemented the precision time kernel used in those production
> systems. Today, at least Solaris and Linux have put up stuff that turns out
> to be absolute poison when attempting things like measuring frequency.
>
> The original model I started with was (a) messier the initial offset and
> tell adjtime() to slew the kernel to that offset; (b) after five minutes
> assume the kernel has largely completed the slew, measure the current offset
> anc compute the frequency. This is a little tricky, since the amount the
> kernel has slewed the time must be added before computing the time
> difference.
>
> Well, this didn't work, apparently because the kernel didn't do what it was
> supposed to do. However, a hint is available in the form of the second phase
> of the training interval where the residual offset is amortized while
> holding the frequency constant. This involves periodically measuring the
> offset and updating the adjtime() programmed offset. This works, as evident
> my previous message. This could be due to a nonlinearity in the adjtime()
> calculation of the slew rate, which is apparently higher the larger the
> programmed offset. Apparently, the repeated calls to adjtime() eventually
> lowers the offset and thus the slew rate to something reasonable. Whatever
> the cause, the behavior when the frequency file is present is within
> expectations.
>
> So, I did the same thing during the frequency measurement phase, with result
> the following loopstats from a Solaris system with initial offset 122 ms, no
> frequency file and the kernel enabled.
>
> 55506 78196.297 0.122624404 0.000 0.043354274 0.000000 4
> 55506 78200.301 0.108000004 0.000 0.040745455 0.000000 4
> 55506 78208.300 0.083775590 0.000 0.040190338 0.000000 4
> 55506 78226.299 0.047307323 0.000 0.045698174 0.000000 4
> 55506 78244.298 0.026714020 0.000 0.054270636 0.000000 4
> 55506 78262.298 0.015085167 0.000 0.063186252 0.000000 4
> 55506 78280.298 0.008518459 0.000 0.071337915 0.000000 4
> 55506 78298.298 0.004810297 0.000 0.078439342 0.000000 4
> 55506 78316.298 0.002716332 0.000 0.084507033 0.000000 4
> 55506 78334.297 0.001533888 0.000 0.089652370 0.000000 4
> 55506 78352.298 0.000866173 0.000 0.094006017 0.000000 4
> 55506 78370.298 0.000489120 0.000 0.097751274 0.000000 4
> 55506 78388.297 0.000276202 0.000 0.100850407 0.000000 4
> 55506 78406.297 0.000155969 0.000 0.103480985 0.000000 4
> 55506 78424.297 0.000088074 0.000 0.105713875 0.000000 4
> 55506 78442.297 0.000049735 0.000 0.107604976 0.000000 4
> 55506 78460.297 0.000028085 0.000 0.109209608 0.000000 4
> 55506 78478.298 0.000015859 0.000 0.110570569 0.000000 4
> 55506 78496.298 0.003133702 10.416 0.111724541 0.000000 4
> 55506 78512.297 0.001806182 10.416 0.104509792 0.000000 4
> 55506 78528.297 0.000873748 10.416 0.097760515 0.000000 4
> 55506 78544.297 0.000362151 10.416 0.091446767 0.000000 4
> 55506 78656.297 0.000353000 12.931 0.085540618 0.889337 4
> 55506 78688.298 0.000354000 13.104 0.080015921 0.834140 4
> 55506 78720.297 0.000226000 13.214 0.074848054 0.781241 4
> 55506 78736.297 -0.000163000 13.175 0.070014079 0.730920 4
> 55506 78864.299 -0.000234000 12.718 0.065492179 0.702547 4
> 55506 78912.299 -0.000289000 12.506 0.061262326 0.661420 4
> 55506 78944.298 -0.000286000 12.366 0.057305659 0.620669 4
> 55506 78992.297 -0.000286000 12.157 0.053604536 0.585287 5
> 55506 79008.297 -0.000233000 12.143 0.050142455 0.547509 5
> 55506 79269.297 -0.000469000 11.676 0.046904046 0.538099 5
> 55506 79430.297 -0.000319000 11.480 0.043874749 0.508089 5
> 55506 79495.297 -0.000265000 11.414 0.041041075 0.475841 5
> 55506 79755.304 -0.000206000 11.210 0.038390415 0.450932 5
> 55506 79852.297 -0.000257000 11.115 0.035910950 0.423146 5
> 55506 79949.297 -0.000249000 11.023 0.033591618 0.397155 6
>
> It starts at second 78196 with offset 122 ms and frequency zero. At 300 s
> later, second 78496, the frequency is set at 10.496, which happens to be
> within 1 PPM of the nominal value. At this point the residual offset is
> about 3.1 ms. At second 78544 the residual offset drops below 0.5 ms and the
> frequency clamp is removed. However, there is about a 0.3 ms residual
> offset, which at this low poll interval of 16 s and low time constant makes
> the frequency loop rather sensitive, so the frequency jumps to 12.9 PPM.
> While this slowly subsides to the e nominal value, note the residual offset
> stays below 0.35 ms. Victory is declared
>
> I haven't tried this on other machines, but the sheer blunderbuss approach
> here should tame even them. Your exploits to the contrary are invited. The
> new code is in the backroom, but not yet a snapshot.
>
> Dave
>
> Dave Hart wrote:
>
> On Sat, Nov 6, 2010 at 03:34 UTC, David L. Mills <mills at udel.edu> wrote:
>
>
> Now to the apparent initial frequency error. This is new, as tests in the
> past have not confirmed that. I need to plant some debug code in
> direct-freq().
>
>
> I ran several more tests without a drift file on the same FreeBSD 6.4
> machine, but now with the daemon loop.  The kernel frequency was reset
> with ntptime -f 0.  This is using ntpd 4.2.7p78 with four LAN sources
> each with less than 500ms delay on gigabit ethernet, maxpoll 6 and
> iburst on each.  The machine's drift when settled stays over 79 and
> under 81 PPM.
>
> 55506 60099.298 0.112224703 0.000 0.039677424 0.000000 6
> 55506 60430.299 0.087985591 265.808 0.031875465 0.000000 6
> 55506 60497.299 0.082268047 265.808 0.029885212 0.000000 6
> 55506 60501.299 0.063703305 265.808 0.028715263 0.000000 6
> 55506 60566.299 0.044976216 265.808 0.027664662 0.000000 6
> 55506 60570.299 0.035161159 265.808 0.026109553 0.000000 6
> 55506 60632.299 0.016835865 265.808 0.025268008 0.000000 6
> 55506 60637.300 0.007505765 265.808 0.023865132 0.000000 6
> 55506 60699.299 -0.005871398 265.808 0.022819291 0.000000 6
> 55506 60703.299 -0.012182324 265.808 0.021461792 0.000000 6
>
> Above I slowed the clock by 110ms before starting ntpd, and its
> frequency estimate is 3x too big.
>
> 55506 61035.172 -0.109110664 0.000 0.038576445 0.000000 6
> 55506 61364.172 -0.039509331 -120.080 0.047442141 0.000000 6
> 55506 61432.172 -0.018407984 -120.080 0.045000783 0.000000 6
> 55506 61441.171 -0.000743150 -120.080 0.042555170 0.000000 6
> 55506 61570.172 -0.039411530 -120.383 0.042088955 0.107139 6
> 55506 61907.172 0.077963129 -118.817 0.057202679 0.562671 6
> 55506 62109.172 0.112914955 -117.457 0.054916590 0.712782 6
> 55506 62588.325 0.000000000 -117.457 0.000001907 0.666746 6
> 55506 62597.324 0.036879681 -117.437 0.013038936 0.623723 6
>
> This time opposite offset and the drift ends up with the wrong sign.
>
> 55506 62673.088 0.046002361 0.000 0.016264291 0.000000 6
> 55506 63004.087 0.036022038 108.824 0.016594865 0.000000 6
> 55506 63072.088 0.024200794 108.824 0.016075870 0.000000 6
> 55506 63076.087 0.015639317 108.824 0.015339223 0.000000 6
> 55506 63139.087 0.007153841 108.824 0.014658809 0.000000 6
> 55506 63144.087 -0.001147804 108.824 0.014022670 0.000000 6
> 55506 63342.087 0.010581006 108.949 0.013756870 0.044150 6
> 55506 63546.087 -0.007289204 108.860 0.014335728 0.051841 6
> 55506 64089.087 -0.018442062 108.263 0.013977562 0.216530 6
> 55506 64156.087 -0.025361028 108.162 0.013301681 0.205686 6
> 55506 64224.087 -0.025423666 108.059 0.012442603 0.195821 6
>
> 46ms slow, frequency is ~28 PPM too large.
>
> 55506 64548.716 0.001700028 0.000 0.000601053 0.000000 6
> 55506 64879.717 0.023679569 71.539 0.010183162 0.000000 6
> 55506 64946.717 0.019872424 71.539 0.009620108 0.000000 6
> 55506 65013.717 0.002736900 71.539 0.010848108 0.000000 6
> 55506 65017.717 -0.008305963 71.539 0.010872643 0.000000 6
> 55506 65082.716 -0.004770959 71.539 0.010246931 0.000000 6
> 55506 65148.717 0.001608567 71.539 0.009846926 0.000000 6
> 55506 65219.717 0.012919477 71.594 0.010041603 0.019330 6
> 55506 65346.717 0.011396322 71.680 0.009408484 0.035457 6
> 55506 65486.716 0.003467074 71.709 0.009236544 0.034709 6
> 55506 65828.717 0.004913697 71.809 0.008655121 0.048044 6
> 55506 66236.717 0.006136544 71.959 0.008107660 0.069307 6
> 55506 66627.716 0.007779940 72.140 0.007606245 0.091173 6
> 55506 66776.716 0.009039619 72.220 0.007128916 0.089883 6
> 55506 67230.717 0.009392249 72.474 0.006669656 0.123060 6
> 55506 67373.716 0.009373844 72.554 0.006238895 0.118527 6
> 55506 67658.716 0.009579650 72.717 0.005836406 0.124912 6
> 55506 67908.717 0.009567647 72.860 0.005459459 0.127253 6
> 55506 67977.716 0.009286340 72.898 0.005107825 0.119797 6
> 55506 68513.717 0.009503342 73.201 0.004778549 0.155178 6
> 55506 68642.716 0.009570171 73.275 0.004469985 0.147469 6
> 55506 69168.716 0.009184942 73.563 0.004183506 0.171447 6
> 55506 69233.716 0.009189485 73.599 0.003913312 0.160868 6
> 55506 69365.716 0.009375908 73.672 0.003661161 0.152721 6
> 55506 69432.717 0.009193983 73.709 0.003425307 0.143446 6
> 55506 69959.717 0.008999743 73.992 0.003204817 0.167315 6
> 55506 70090.717 0.009024846 74.062 0.002997845 0.158480 6
> 55506 70155.716 0.008902531 74.097 0.002804561 0.148745 6
> 55506 70350.716 0.008570129 74.196 0.002626057 0.143526 6
> 55506 70672.716 0.008251968 74.355 0.002459026 0.145465 6
> 55506 71197.716 0.007350799 74.585 0.002322169 0.158521 6
> 55506 71456.716 0.007408970 74.699 0.002172288 0.153698 6
> 55506 71850.716 0.007506679 74.875 0.002032283 0.156700 6
> 55506 72376.716 0.007566595 75.113 0.001901145 0.168879 6
> 55506 72899.717 0.007325361 75.341 0.001780402 0.177408 6
> 55506 72965.716 0.007008212 75.368 0.001669184 0.166236 6
> 55506 73491.716 0.006596605 75.575 0.001568146 0.171833 6
> 55506 73689.716 0.006589897 75.653 0.001466868 0.163070 6
> 55506 74212.717 0.006427589 75.853 0.001373329 0.168186 6
> 55506 74407.717 0.006501221 75.929 0.001284895 0.159575 6
> 55506 74537.723 0.006513531 75.979 0.001201917 0.150332 6
> 55506 74672.717 0.006297412 76.030 0.001126884 0.141759 6
> 55506 74999.716 0.006044827 76.148 0.001057880 0.138992 6
> 55506 75524.716 0.005710565 76.327 0.000996588 0.144553 6
> 55506 75981.716 0.005532070 76.477 0.000934356 0.145334 6
> 55506 76313.716 0.005505819 76.586 0.000874059 0.141300 6
> 55506 76442.716 0.005524893 76.629 0.000817635 0.133025 6
> 55506 76768.716 0.005369956 76.733 0.000766787 0.129787 6
> 55506 77228.716 0.004834798 76.866 0.000741799 0.130137 6
> 55506 77685.716 0.004784225 76.996 0.000694120 0.130159 6
> 55506 78207.716 0.004621958 77.140 0.000651820 0.131942 6
> 55506 78273.716 0.004610433 77.158 0.000609735 0.123587 6
> 55506 78667.717 0.004535789 77.264 0.000570965 0.121585 6
> 55506 79191.716 0.004254460 77.397 0.000543272 0.123053 6
> 55506 79387.724 0.004210196 77.447 0.000508425 0.116412 6
> 55506 79451.716 0.004094866 77.462 0.000477333 0.109034 6
> 55506 79648.717 0.004053887 77.510 0.000446739 0.103371 6
> 55506 80173.716 0.003811266 77.629 0.000426599 0.105488 6
> 55506 80239.717 0.003807079 77.644 0.000399050 0.098817 6
> 55506 80761.716 0.003781913 77.762 0.000373383 0.101366 6
> 55506 80826.716 0.003742947 77.776 0.000349539 0.094957 6
> 55506 81286.717 0.003719909 77.878 0.000327066 0.095865 6
> 55506 81810.723 0.003575463 77.990 0.000310175 0.097981 6
> 55506 82008.717 0.003563863 78.032 0.000290171 0.092851 6
> 55506 82075.716 0.003460594 78.046 0.000273875 0.086991 6
> 55506 82139.716 0.003368641 78.059 0.000258241 0.081500 6
> 55506 82664.716 0.003331264 78.163 0.000241923 0.084677 6
> 55506 83058.716 0.003307356 78.240 0.000226456 0.083834 6
> 55506 83321.717 0.003079668 78.289 0.000226611 0.080255 6
> 55506 83452.716 0.002969860 78.312 0.000215501 0.075518 6
> 55506 83517.717 0.002958930 78.323 0.000201620 0.070757 6
> 55506 83646.716 0.002923137 78.346 0.000189022 0.066662 6
> 55506 84169.717 0.002828842 78.434 0.000179929 0.069717 6
> 55506 84233.716 0.002829801 78.445 0.000168310 0.065326 6
> 55506 84299.716 0.002810263 78.456 0.000157591 0.061232 6
> 55506 84823.716 0.002667552 78.539 0.000155809 0.064407 6
> 55506 85146.716 0.002627148 78.590 0.000146444 0.062845 6
> 55506 85601.716 0.002466953 78.657 0.000148233 0.063367 6
> 55506 86006.716 0.002419676 78.715 0.000139663 0.062769 6
> 55506 86122.717 0.002411172 78.732 0.000130677 0.059010 6
> 55506 86188.716 0.002383291 78.741 0.000122634 0.055298 6
>
> Under 2ms initial offset, the frequency estimate is ~8 PPM too small.
>
> Cheers,
> Dave Hart
>
>



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