MATLAB: How to cut the signal

csvcutremovesignal

Dear All, I have waveform data in csv file in 'X' and 'Y' axis, the plot is on the figure attached. I want to remove the unneeded signal marked by arrows sign in order to get complete waveform signal. Is there any advice/better algorithm to remove the signal automatically ? My idea is to track the data in a loop then find the '0' value in the 'Y' axis and delete the rows before. Best regards.

Best Answer

How about if you simply find the first and last time that y is negative?

index1 = find(y<0, 1, 'first'); % Find left index
index2 = find(y < 0, 1, 'last'); % Find right index.
% Now crop signal
yCropped = y(index1:index2);

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MATLAB: Cut Sinusoidal signal in a integer number of periods

Hi,

bear in mind that the sampling of your curve might play an important role in the game.

The code below might help you out:

t = linspace(0,10*pi,200); 
x = sin(t); 
zero_crossings_pos = [];
for kind = 1:length(t)-1
    if (x(kind) <= 0) && (x(kind+1) > 0)
    zero_crossings_pos = [zero_crossings_pos kind];
    end
end
figure,
plot(t,x,t,x,'o')
hold on
plot(t(zero_crossings_pos),x(zero_crossings_pos),'r*')
hold off
xlabel('x')
ylabel('sin(x)')
title('sin')
t_crop = t(zero_crossings_pos(2):zero_crossings_pos(5));
x_crop = x(zero_crossings_pos(2):zero_crossings_pos(5));
figure,
plot(t_crop,x_crop)
xlabel('x')
ylabel('sin(x)')
title('Cropped sin')

MATLAB: How to find x range value and calculate average of corresponding peaks in a graph signal

Try this;

index = find(y>100);                            % find peaks
ind = find( diff(x(index)) > 0.01 );            % find start and end of peak searies
index = [index(1) index(ind+1);                 % first row - start of series
        index(ind) index(end)];                 % second row - end series

Best Answer

Related Solutions

MATLAB: Cut Sinusoidal signal in a integer number of periods

MATLAB: How to find x range value and calculate average of corresponding peaks in a graph signal

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