• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT
    Make New Entry, Make Followup Entry

    User name R. Michaels

    Log entry time 16:58:28 on August31,2009

    Entry number 287249

    keyword=ADC18 DAC noise glitch, etc.

    Sometimes the DAC noise "glitches" leading to a glitch in
    the signal (see fig 1).  This was happening in the test crate too,
    and it seems worse with oversampling; though maybe it's not worse
    but you are more likely to see it because of the higher rate.
    This happens on all channels and on ALL boards in the crate 
    simultaneously, so it might be timing board related.  It would be 
    easy to cut out of the data -- look at base or peak, see a 
    discontinuity -- but I need to see if I can eliminate this in 
    the Test Crate.
    On a brighter note, some low-level checks pass:  the CSR is always
    normal (no event-buffer full conditions, etc), the event counters 
    are always synched, the word count is stable, the order of the 
    data is never scrambed.  With this CRL version the first 1 to 5 events
    get the "bad1" flag, but after that its clean.  If I get a chance
    to roll out the new CRL only the 1st event should be bad.

    FIGURE 1