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Entry  Tue Jun 25 23:04:29 2019, Si Xie, drs_exam is always reading out a sin wave 
    Reply  Wed Jun 26 13:08:42 2019, Stefan Ritt, drs_exam is always reading out a sin wave 
       Reply  Wed Jun 26 15:10:09 2019, Si Xie, drs_exam is always reading out a sin wave 
          Reply  Mon Jul 8 14:29:12 2019, Stefan Ritt, drs_exam is always reading out a sin wave 
Message ID: 760     Entry time: Mon Jul 8 14:29:12 2019     In reply to: 758
Author: Stefan Ritt 
Subject: drs_exam is always reading out a sin wave 

Actually in the original drs_exam.cpp the sine wave oscillator is turned off with this command

/* use following line to turn on the internal 100 MHz clock connected to all channels  */
//b->EnableTcal(1);

If you remove the "//" then the generator gets enabled. Probably you did this by accident. With this line commented out, you see the proper input like this:

Event #0 ----------------------
  t1[ns]  u1[mV]  t2[ns] u2[mV]
  0.000     1.9   0.000    -2.4
  0.195     0.5   0.195     0.3
  0.391     0.1   0.391    -1.4
  0.586    -0.7   0.586    -0.4
  0.781    -1.1   0.781    -2.4
  0.977    -0.6   0.977     0.0
  1.172    -1.5   1.172    -2.8
  1.367    -0.4   1.367    -0.6
  1.562    -1.2   1.562    -3.8
  1.758    -1.5   1.758    -1.7
  1.953    -1.0   1.953    -3.3
  2.148    -0.7   2.148    -1.8
  2.344    -1.6   2.344    -4.2
  2.539     0.5   2.539    -1.5
  2.734     0.2   2.734    -3.6
...

167.969    -3.4 167.969    -5.2
168.164    -3.7 168.164    -3.6
168.359     0.0 168.359    -2.0
168.555     1.9 168.555    -0.2
168.750     2.8 168.750    -2.8
168.945     5.4 168.945    -1.4
169.141    18.0 169.141     1.2
169.336    26.6 169.336     2.7
169.531    46.2 169.531     0.4
169.727    56.2 169.727     1.6
169.922    93.3 169.922     0.1
170.117   115.6 170.117     0.0
170.312   174.4 170.312    -1.5
170.508   206.9 170.508    -0.8
170.703   282.2 170.703    -2.4
170.898   328.4 170.898    -1.2
171.094   419.6 171.094    -3.2
171.289   465.8 171.289    -2.5
171.484   500.0 171.484    -2.0
171.680   500.0 171.680    -0.6
171.875   500.0 171.875    -4.0
172.070   500.0 172.070    -1.1
172.266   500.0 172.266    -3.7
172.461   500.0 172.461    -2.1
172.656   500.0 172.656    -5.0
172.852   500.0 172.852    -3.3
173.047   500.0 173.047    -4.8
173.242   500.0 173.242    -4.1
173.438   500.0 173.438    -5.1
173.633   500.0 173.633    -3.3
173.828   500.0 173.828    -6.4
174.023   500.0 174.023    -3.9
174.219   500.0 174.219    -5.5
174.414   500.0 174.414    -3.2
174.609   500.0 174.609    -3.6
174.805   500.0 174.805    -2.6
175.000   500.0 175.000    -5.2
175.195   500.0 175.195    -2.7
175.391   434.3 175.391    -3.9
175.586   391.7 175.586    -2.4
175.781   312.2 175.781    -4.1
175.977   275.7 175.977    -1.8
176.172   202.4 176.172    -3.8
176.367   167.6 176.367    -1.4
176.562   117.4 176.562    -2.9
176.758    96.1 176.758    -2.3
176.953    62.8 176.953    -3.3
177.148    49.1 177.148    -1.8
177.344    35.9 177.344    -4.3
177.539    33.4 177.539    -2.6
177.734    30.4 177.734    -4.2
...

 

Si Xie wrote:

I see. Where is the code that we can use to turn off the generator? I thought the example is taking data with CH1 as the trigger.

For our board, which is BoardType == 9, it is running these lines:

      b->EnableTrigger(1, 0);           // enable hardware trigger
      b->SetTriggerSource(1<<0);        // set CH1 as source

Is that not using the hardware trigger with CH1 as the source?

 

Stefan Ritt wrote:

Sure, that’s correct. The example program turns on the internal sine wave generator in case people don’t have a real signal. That’s why it’s called „example“. Find the code which turns on the generator and change it. You will also have to change the trigger settings depending on your actual signal.

Stefan

 

Si Xie wrote:

We are using the drs_exam.cpp to read out waveforms, but it seems to be outputting only sin waves on all channels - as if it was reading out the simulated waveform from the oscilloscope program if we run it without the board plugged in. Does anyone know what is causing this?

We are taking data with a pulser plugged into channel 1, which produces a single pulse with width of 8ns, and nothing plugged into channel 2. 

Our board is as follows:

Found DRS4 evaluation board, serial #2567, firmware revision 21305
Board type: 9

The output is something like the following:

Event #0 ----------------------
  t1[ns]  u1[mV]  t2[ns] u2[mV]
  0.000  -452.7   0.026  -469.3
  0.289  -460.8   0.293  -469.8
  0.413  -477.3   0.400  -481.5
  0.642  -485.3   0.650  -482.4
  0.806  -486.9   0.821  -477.8
  1.086  -476.8   1.085  -457.2
  1.183  -467.3   1.162  -446.4
  1.450  -435.6   1.459  -405.1
  1.619  -410.1   1.630  -373.3
  1.843  -366.2   1.851  -323.9
  1.945  -342.9   1.948  -298.9
  2.221  -275.7   2.210  -229.3
  2.359  -237.6   2.357  -187.6
  2.602  -165.6   2.609  -111.2
  2.687  -141.1   2.697   -84.3
  2.976   -50.5   2.987     5.5
  3.164     8.4   3.144    53.3
  3.377    73.9   3.384   124.2
  3.503   111.4   3.506   158.0
  3.753   182.0   3.769   226.9
  3.924   227.5   3.929   265.8
 

 

 

 

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