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Entry  Mon Dec 5 10:39:16 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue 
    Reply  Tue Dec 6 09:02:17 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue 
       Reply  Tue Dec 6 10:38:19 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue Screenshot.pnggps_time_offset.png
          Reply  Tue Dec 6 11:22:58 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue Screenshot-3.png
             Reply  Tue Dec 6 16:55:51 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue Screenshot.png
                Reply  Wed Dec 7 08:14:05 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue Screenshot-1.png
                   Reply  Wed Dec 7 16:27:11 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue 
                      Reply  Thu Dec 8 09:26:10 2016, Gabriele, Electronics, Configuration, Trying to debug GPS time issue figure_1.pngfigure_1.png
Message ID: 224     Entry time: Mon Dec 5 10:39:16 2016     Reply to this: 227
Author: Gabriele 
Type: Electronics 
Category: Configuration 
Subject: Trying to debug GPS time issue 

For a long time I had problems with the GPS time in frames being different from the real one.

This morning I rebooted the cymac3 and swapped the function generator with a new one.

I tested the GPS time in frames by switching on teh ESD noise at a given GPS time and checking the frames. The times are aligned.

I'll have to wait and see if this remains stable over time (in the past i saw an acculation of few seconds per day)

 

EDIT: I checked the two SR DS345 one against the other. Indeed, when bpth set to generate 65536 Hz, there is a continuos drift in the relative phase, accounting for one cycle over about 3.9 seconds. This would sum up to one second over ~256000 seconds, or about 3.5 days. It seems more or less comparable with the amount of GPS time mis-syncronization I saw. I'll have to wait a few days to see if the new clock is stable.

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