Meassuring energy of a pulse

[Ellile]

Hello,

How do you calculate the energy of a pulse in the scope part of AD3. In my Keysight scope I use a meassurement caled "Area under curve" function and zoom in to the area I want to calculate.  

Br

Leif G

[Ellile]

I might found a solution to it.

Would it be correct to use a math channel like this?

sum += (C1*C1)/20000 * 1/Rate

return sum

Where C1 is the voltage meassured over the 20k resistor. 

The time aspect I am alittlebit unsure about but the result seems to be correct when I use Extend with T1 and T2 in a meassurement script like this

value = 0

data = Channel.getData(T1,T2)

data.forEach(function(sample){ value+=sample })

value /= data.length

[artvvb]

Hi Ellile,

If the other end of your resistor is grounded, that should be correct - the "Energy through C1 100R C2" example, which seems to be what you're basing this on, calculates power from the current through the resistor multiplied by the voltage at the top of the resistor. Current is calculated as the voltage difference across the resistor divided by the resistance in ohms - so, if C2 would measure 0 by the other end of the resistor being grounded, the modified example is fine. Energy is calculated by integrating the power - summing it all up, with each sample multiplied by the amount of time between samples.

There might be a little bit of error from the digitization process, but that's what having a sufficient sample rate is for.

Thanks,

Arthur

Edit: Moved the thread to the T&M subforum, which is more appropriate for this topic.

[Ellile]

Thanks for looking into it for me :) and I more and more are confident that this seems to be the way of doing the energy calculation. I use a diff probe as the signal is not common to the rest of the setup so ground shound therefore be ok. It might be some offset issue with that probe to be introduced but for now it is ok.

My next issue now is to be able to calculate the amount of pulses having this energy. I struggle a lot to be able to calc that in a good way.

If you look at mye attached scope picture you see that in this case it calc this trigg almost correct (6 cycles) but it is actual 7, but in most cases this is even worse, 0, 1 etc

How do I do this calc exact? Each pulse is approx 50uS wide. Another way maye is to zoom inn on the 50uS signal and count the amount of trigg, but I have not found a good way of doing that eighter.  

 

it could