TRG vs GPS Statistics of May-June 2000 run


Plots of data from 05-11-2000 00:00:59 to 06-21-2000 09:56:58


Relative time between spills (via TRG 48-bit clock)



same as above, but zoomed in [2.17 ... 2.21] and with histogram


TRG oscillator drift from 50 MHz (*1)



Absolute spill time difference between GPS1 and GPS2 (*3)


Relative spill time difference between GPS1 and TRG (*2)


Relative spill time difference between GPS2 and TRG (*2)


Histograms

Note: y axis is log scale


Notes

(*1)   Both, the TRG module and LTC module each use an internal, free-running 50 MHz crystal oscillator (independent) for their clock counters. The two oscillators are not temperature compensated! Therefore, any change of the room temperature in the North Hall control room causes them to drift. Cooler temperatures usually result in higher frquencies than at warmer temperatures.
(*2)   Absolute TRG clock vs. GPS time measurements cannot be made due to the mentioned temperature-dependent TRG oscillator drifts, as shown in the wave forms of the plots above. The waves are inverse proportional to temperature changes in the North Hall.
(*3)   GPS2 had four 12.5-minute satellite synchronization problems during this run period, caused by a firmware bug on the Motorola UT-plus Oncore module. During these 12.5-minute sections, GPS2 data is totally wrong and should not be used (GPS1 is ok, though):
  • 05/17/2000 from 01:53:57 until 02:06:29 (UTC),
  • 05/19/2000 from 13:03:57 until 13:16:26 (UTC),
  • 05/31/2000 from 04:48:56 until 05:01:28 (UTC),
  • 06/06/2000 from 19:51:16 until 20:03:57 (UTC).


See also list of errors.