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Matlab and Signals processing

  1. Sep 26, 2012 #1
    I have inputed the following, I was given a signal and told to plot it in a time domain. The signal ECG is a data file and imported.

    N = 15000;
    fs = 250;
    t = linspace(0, 60, N);
    %signal = ecg data = ecg

    subplot (2,1,1);
    plot (t,ecg);
    title ('Time-Domain ECG')
    xlabel ('Time (s)')
    ylabel ('Magnitude')

    The above works just fine, but I wish to focus on a part of the data.

    The problem is I do not know how to isolate a segment of the data, I'm not very experienced in MATLAB. The data represents heartbeats, and my goal is to plot one from the raw data, say for instance from time 50-60.

    I had thought perhaps the following would work:

    plot (t(50:60),ecg(my start point:end);

    Obviously it does not, so I'm asking for some help.
  2. jcsd
  3. Sep 26, 2012 #2


    User Avatar
    Science Advisor

    Try this Tom
    Code (Text):

    idx = find(t>50 & t<60);
  4. Sep 26, 2012 #3
    Thank you very much, you have ended a great deal of frustration for what amounted to a simple problem. I hate knowing what you want to do but not knowing the correct terminology to search for the help. I doubt this class will teach me much about signals and systems in the end, but I think I'll be better at MATLAB for my trouble.

    Any suggestions on where to actually learn signals and systems would be appreciated, in terms of self-study.
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