TRG vs GPS Statistics of Oct-Nov 1999 run


Plots of data from 10-27-1999 10:38:58 to 11-23-1999 23:59:59


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.
(*2)   During this run period, GPS2 had one 12.5-minute satellite synchronization problem, caused by a firmware bug on the Motorola UT-plus Oncore module. During this 12.5-minute section GPS2 data is totally wrong and should not be used (GPS1 is ok, though):
  • 11/06/1999 from 13:51:26 until 14:04:00 (UTC).


See also list of errors.