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Entry  Sat Feb 12 13:06:56 2022, Matias Senger, Cannot trigger on pulses, have to trigger on undershoot 
    Reply  Tue Feb 15 12:02:29 2022, Stefan Ritt, Cannot trigger on pulses, have to trigger on undershoot 
Message ID: 862     Entry time: Sat Feb 12 13:06:56 2022     Reply to this: 864
Author: Matias Senger 
Subject: Cannot trigger on pulses, have to trigger on undershoot 

I am using the DRS4 board trying to measure pulses produced by an LGAD. I have no prior experience with this board, have just installed the `drsosc` application and am exploring. I am experiencing some strange trigger behavior. Consider the following screenshot:

 

Here nothing is strange, the board is triggering on the undershoot and it is working fine, I can trigger on rising/falling edge, different levels, etc.

Now, the strange thing is that if I pull the trigger up to trigger on the pulse itself it stops triggering:

I have tried many different setups for the trigger (rising, falling edge, different levels, etc) and nothing works. In the undershoot, everything works.

I have tried with the internal test signal and it works fine:

What could be the problem?

I have run the voltage and time calibrations as suggested in the manual.

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