How to integrate imported data with specified limits.

Hi,

I am studying switchies losses during swithcing transients of certain devices. I have imported the swithcing data from a different software an uploded it into MATLAB. I am trying to calcuate the area under the curve from the data that has been imported. I have used the Trapz rule and can find out the area under the whole curve, however when I am struggling to apply limits.

I have also looked at the integration Funciton however, I dont know how to run my waveform into a specific function.

I have included the full wavform, and then a section of it, which I wish to calculate the area under.

Thanks,

J

[M Herper]

Hi,

trapz integrates the whole array, so you can create a subset of the array to be integrated.

Here a little code sample:

lower_limit = 2;

upper_limit = 4;

stepsize = 1;

t = lower_limit:stepsize:upper_limit;

raw_data = [1 1 1 1 1 1 1 1]

data_to_be_integrated = raw_data(lower_limit:upper_limit)

trapz(t, data_to_be_integrated) % ans = 2

cumtrapz(t, data_to_be_integrated) % ans = 1x3: 0 1 2

Answer 1

[Jiri Hajek]

If you data is e.g. X,Y, both vectors 1:N, you can create suitable subinterval by assigning Xsub = X(i1:i2), Ysub = Y(i1:i2) and then applying the trapz function on these new data vectors.