I have a question on plotting a specific part of data from a larger section,

Below shows my code for plotting two waveforms over 12 seconds,the workspace variable D10 is 240001 x 2 double, I am particularly interested in a section of this data between 5 and 8 seconds and I want to plot it separately on its own, several attempts have given errors so any help is much appreciated.

Thanking you in advance

t = [((0:length(D10)-1))]*1/20000; plot (t,D10); xlabel('Time(s)'), ylabel('Pu') title ('Engine and Generator Shaft Speed')

Answer 1

[Wayne King]

It looks like your sampling frequency is 20 kHz

I'll just create a noise signal as an example

   fs = 2e4;
   D10 = randn(240001,1);
   t = 0:1/fs:(240001*1/fs)-1/fs;
   dt = 1/fs;
   idxstart = round(5/dt);
   idxend = round(8/dt);
   plot(t(idxstart:idxend),D10(idxstart:idxend));
   set(gca,'xlim',[5 8])
   xlabel('Time(s)'), ylabel('Pu'), title ('Engine and Generator Shaft Speed')

[Bryan]

Hi Wayne

Thanks for your answer,it has really improved my plotting, however the plot wont display the two graphs contained in the D10 data, to give a little background info the two graphs should show as a reference trajectory (Step input)and a control loop response (Step response), My plot will only show the step input

Thanks again