AdV-DAQ (Data Acquisition and Global Control)bonnand, masserot, mours - 18:23 Monday 25 June 2018 (41978)
Print this reportSwapping the GPS receiversThis morning, to fix the 10 MHz clock issue, we replaced the master GPS receiver that was located on the top of the timing rack, by the spare GPS receiver that was just below. Actually, we did not move the receivers, but thanks to Fabio, we just swapped the IRIG-B and 10 MHz cables at the output of the two receivers (see the two red arrows on the attached picture). The names of the channels that monitor the timing system were unchanged.
Then the DAQbox that were slaved on the 10 MHz clock were reinitialized to align them again on the IRIG-B, the various local controls on the suspended benches restarted, and the ITF recovery could start.
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fiori, paoletti - 11:40 Tuesday 26 June 2018 (41992)
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The spare GPS receiver looks much cleaner. The 10MHz clock noise reduced significantly (Figure 1). Figure 2 shows the consequent improvement in PRCL and DARM. Also the residual noise at 380Hz disappeared from hrec (Figure 3).
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fiori, paoletti - 11:57 Tuesday 26 June 2018 (41993)
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The 10MHz clock noise in not yet at the level of O2, but several structures (like 380Hz) are removed.