Hi, how can I divide this signal into 3 segments? The first segment I want to be the signal before the major peak, the second segment would be the major peak and the last segment would be the signal after the peak.

The first segment I want to be the signal before the major peak, the second segment would be the major peak and the third segment would be the signal after the major peak. You can find the signal attached.

Answer 1

[Star Strider]

One approach:

The Code —

D = load('signals (1).mat');
Signal = D.Signal;                                                                                      % Get ‘Signal’

N = length(Signal);
t = linspace(0, 1, N) * N;                                                                              % Create Time Vector

[pk,loc] = findpeaks(Signal, 'MinPeakHeight',1);                                                        % Determine Indices Of Various Components
[trofs,trlocs] = findpeaks(-Signal);
ltidx = find(trlocs < loc, 1, 'last');
gtidx = find(trlocs > loc, 1, 'first');

Out{1} = {Signal(1:trlocs(ltidx)); Signal(trlocs(ltidx)+1:trlocs(gtidx)-1); Signal(trlocs(gtidx):end)}; % ‘Signal’ Cell Array
Out{2} = {t(1:trlocs(ltidx)); t(trlocs(ltidx)+1:trlocs(gtidx)-1); t(trlocs(gtidx):N)};                  % ‘t’ Cell Array

figure
plot(Out{2}{1}, Out{1}{1}, 'r')
hold on
plot(Out{2}{2}, Out{1}{2}, 'g')
plot(Out{2}{3}, Out{1}{3}, 'b')
hold off
grid

The Plot —

[Hannah Oduntan]

Thank you for this answer, but I'm trying to actually separate each segment into their own individual graph, if that makes sense.

[Image Analyst]

Then how about using subplot():

subplot(2, 2, 1);
plot(Out{2}{1}, Out{1}{1}, 'r')
subplot(2, 2, 2);
plot(Out{2}{2}, Out{1}{2}, 'g')
subplot(2, 2, 3);
plot(Out{2}{3}, Out{1}{3}, 'b')
grid

[Star Strider]

My pleasure.

@Image Analyst — Thank you. That is exactly what I would have suggested.

@Hannah Oduntan — My code does exactly what you want. You did not specify how you wanted the results presented, so I combined them in one plot to demonstrate the results my code produces. Use Image Analyst’s subplot code to present each segment in a separate axis.

The Plots —

[Hannah Oduntan]

Yes this is it, thank you for the help!

[Image Analyst]

Note that things like "grid on", title(), xlabel(), ylabel(), xticks(), yticks(), etc. will have to be applied individually to each plot right after you plot it.

You could also use

subplot(3, 1, 1);
subplot(3, 1, 2);
subplot(3, 1, 3);

if you want them all three full screen width stacked vertically.

[Hannah Oduntan]

Both ways are perfectly fine, thank you.

[Star Strider]

As always, my pleasure!

@IA — Thank you.