Why does findchangepts doesn't work right?

Hey guys, For the attached data file i use the following code so i can find the areas for each of the four separate waves:

D = load('008a_100Hz.mat');
Ch9 = D.Channel_9_Data;
tv = D.Channel_1_Data;                                              % Time Vector

[lpt,rsd] = findchangepts(Ch9, 'Statistic','rms', 'MaxNumChanges',8);
for k1 = 1:2:numel(lpt)-1
    sig_seg{(k1+1)/2,1} = Ch9(lpt(k1):lpt(k1+1));                   % Signal Values At Each Segment
    sig_seg{(k1+1)/2,2} = lpt(k1):lpt(k1+1);                        % Index Range
end    

vl = bsxfun(@times, ones(numel(lpt), 2), [min(Ch9) max(Ch9)]);      % Create Vertical Lines For ‘figure(1)’

figure(1)
plot(tv, Ch9)
hold on
plot([tv(lpt),tv(lpt)]', vl', '-r', 'LineWidth',1.5)
hold off
grid

With the code I get sth. like this:

The second vertical line should be on the right of the first waves. Any ideas how that might work? Thanks people:)

[jonas]

Related Q

https://se.mathworks.com/matlabcentral/answers/418641-how-to-create-plots-for-special-areas-of-an-array

Answer 1

[Greg Dionne]

If you have R2016b or later try:

Fs = 100;
[sst,f] = fsst(Ch9,Fs,kaiser(512,10));
fridge = tfridge(sst,f,10,'NumRidges',1);
findchangepts(fridge,'Statistic','mean','MaxNumChanges',8)