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Entry  Wed Apr 27 20:04:12 2016, Abaz Kryemadhi, Best settings for time measurements 
    Reply  Thu Apr 28 15:46:34 2016, Stefan Ritt, Best settings for time measurements 
Message ID: 518     Entry time: Thu Apr 28 15:46:34 2016     In reply to: 517
Author: Stefan Ritt 
Subject: Best settings for time measurements 

The DRS4 chip has been designed to work best at high sampling speeds. At 700 MSPS, the chip is at it's limit and timing is very poorr (ns?). In order to get good timing, run it at least at 2 GSPS.

Stefan

Abaz Kryemadhi wrote:

I am studing some pulses that are about 200-300 ns wide and a rise time of few ns,    which settings would be best for coincidence time measurements?

In some preliminary work I found for 700 MegaS the time measurement is better without time calibration (in -0.05 to 1V) rather than with time calibration in -0.5 to 0.5,  my pulses are about 60 mV.   Is it expected that always with time calibration time accuracy would be better or depends?   

Also I use this code snippet to find time for channel 1 and the same idea for chan. 2.

// find peak in channel 1 above threshold
      for (i=0 ; i<1022 ; i++)
         if (waveform[0][i] < threshold1 && waveform[0][i+1] >= threshold1) {
            tt1 = (threshold1-waveform[0][i])/(waveform[0][i+1]-waveform[0][i])*(time[0][i+1]-time[0][i])+time[0][i];
            break;
         }

 

Thanks!

Abaz

 

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