PicoScope 7 Software
Available on Windows, Mac and Linux
Deadtime measurement
Deadtime measurement
Dear all,
this is not a beginner's question but rather a setup / calibration of the device question. Please move, if this is wrong for this sub-forum.
We are characterising a picoscope 3406D MSO and try to measure the gap time (deadtime + setup time) between rapid block mode triggers by using regular pulses from a signal generator (10mV Amplitude, 20ns wide, 1kHz-10MHz). Using the method layed out in this article*, Chapter 3.1, we got a gap time of 2.161us as opposed to the <2us stated in the programmer's guide. We took the data using a self-written python program**
1) Any idea how the gap time was measured from the company to arrive at <2us?
Doing these measurements we observed strange effects:
2) "Saturation" of the rate (number of captures divided by time for the rapid block (taken from CPU time)) at 1 and 2 MHz giving a fixed upper rate of ~360kHz. See attached Fig. showing the histogram of rates
3) "Oscillation" of the rate at 5 and 10MHz input rate: the rate changes between 2 values in subsequent blocks. See attached Fig. showing our "raw" data over the time of 1h.
Any thoughts on these questions would be great!
Anna
*https://www.sciencedirect.com/science/a ... 3318302596
**https://github.com/Annalein214/picogui
this is not a beginner's question but rather a setup / calibration of the device question. Please move, if this is wrong for this sub-forum.
We are characterising a picoscope 3406D MSO and try to measure the gap time (deadtime + setup time) between rapid block mode triggers by using regular pulses from a signal generator (10mV Amplitude, 20ns wide, 1kHz-10MHz). Using the method layed out in this article*, Chapter 3.1, we got a gap time of 2.161us as opposed to the <2us stated in the programmer's guide. We took the data using a self-written python program**
1) Any idea how the gap time was measured from the company to arrive at <2us?
Doing these measurements we observed strange effects:
2) "Saturation" of the rate (number of captures divided by time for the rapid block (taken from CPU time)) at 1 and 2 MHz giving a fixed upper rate of ~360kHz. See attached Fig. showing the histogram of rates
3) "Oscillation" of the rate at 5 and 10MHz input rate: the rate changes between 2 values in subsequent blocks. See attached Fig. showing our "raw" data over the time of 1h.
Any thoughts on these questions would be great!
Anna
*https://www.sciencedirect.com/science/a ... 3318302596
**https://github.com/Annalein214/picogui
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Re: Deadtime measurement
Hi Anna,
To answer your question the dead-time in between captures for Rapid Block Mode/Rapid trigger mode captures is heavily dependent upon the time required to re-arm the Trigger (which, for instance, changes quite dramatically with the Sample Rate). I created a method to determine the re-arm time, for another customer who sent us a support request on our Help Desk, but didn't have time to formally turn it into a guide for the forum.
I'm responding to this quite late, so if this is still an problem for you then I can finish that off and post it here.
Regards,
Gerry
To answer your question the dead-time in between captures for Rapid Block Mode/Rapid trigger mode captures is heavily dependent upon the time required to re-arm the Trigger (which, for instance, changes quite dramatically with the Sample Rate). I created a method to determine the re-arm time, for another customer who sent us a support request on our Help Desk, but didn't have time to formally turn it into a guide for the forum.
I'm responding to this quite late, so if this is still an problem for you then I can finish that off and post it here.
Regards,
Gerry
Gerry
Technical Specialist
Technical Specialist
Re: Deadtime measurement
Hi Gerry,
yes this is still an open question. My student is still working on it. I think she wants to finalize within a week, though.
I think you have my mail address as we are writing about the PicoPyGui App of mine. So you could also send a not so polished version via mail, if this accelerates things.
Best regards,
Anna
yes this is still an open question. My student is still working on it. I think she wants to finalize within a week, though.
I think you have my mail address as we are writing about the PicoPyGui App of mine. So you could also send a not so polished version via mail, if this accelerates things.
Best regards,
Anna
Re: Deadtime measurement
Hi Anna,
In case you haven't seen it, I did send an updated, but still rough version, to you via email (still needs work on it to be able to post it here).
Regards,
Gerry
In case you haven't seen it, I did send an updated, but still rough version, to you via email (still needs work on it to be able to post it here).
Regards,
Gerry
Gerry
Technical Specialist
Technical Specialist