MATLAB: How to correct this error

MATLABmatlab function

Hello

I have done this program , no error is displayed but any curve is displayed.

Can you help me

clc; clear ; close all;

% acceleartion + displacement

cd Z:\Stage\Travail_fait\marwa

load data1; tmp = data1(:,1); disp = data1(:,2); acc = data1(:,3);

figure(1) plot(tmp, acc, 'b',tmp,acc,'r.') xlable('time (s)'); ylabel('Acceleration (ms^(-2))');

Best Answer

Hi,

to show disp over tmp Change the plot command:

plot(tmp, acc, 'b',tmp,disp,'r.')

which will give you this result:

You could also work with subplots using the following code:

figure(1)
subplot(2,1,1)
plot(tmp, acc, 'b') 
xlabel('time (s)');
ylabel('Acceleration (ms^(-2))');
subplot(2,1,2)
plot(tmp, disp, 'b') 
xlabel('time (s)');
ylabel('Displacement');

Which gives you:

Best regards

Stephan

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I will help you out a bit with the signal processing, and I will let you do the heart rate and all other necessary calculations:

fidi = fopen('Biza Ferreira ecg16.txt', 'rt');
Data = textscan(fidi, repmat('%f', 1, 11), 'Delimiter','\t', 'CollectOutput', 1, 'HeaderLines',8);
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Fn = Fs/2;                                                          % Nyquist Frequency
Ts = 1/Fs;                                                          % Sampling Interval (sec)
EKG = Data{:}(:,4);                                                 % EKG Data
T = [0:size(EKG,1)-1]*Ts;                                           % Time Vector
Rp =  5;                                                            % PAssband Ripple (dB)
Rs = 25;                                                            % Stopband Ripple (dB)
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grid
axis([0  2.5    ylim])                                              % Comment This Out To See The Entire Trace

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grid
axis([0  2.5    ylim])                                              % Comment This Out To See The Entire Trace
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xlabel('Time (sec)')
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It is generally necessary to filter an EKG signal to remove the wandering baseline (usually due to respiratory motion) and high-frequency noise. This EKG had a bit of high-frequency noise, so I used a Butterworth bandpass filter to filter the noise and the baseline drift to get a stable baseline. I then used the findpeaks function to locate the R-waves and their times, since in this EKG it will work for that purpose. The best way to understand this code is to read the documentation on the various functions to understand what they do and how I used them here.

ABNORMAL EKG I am not certain where you got this EKG, and I am not certain what lead it is, but it is distinctly abnormal. The ST segment should be isoelectric in a healthy EKG, and there are about 2 mV of ST segment depression in this one. There is also a degree of electrical alternans in the R-wave amplitudes. The intervals and amplitudes are otherwise within normal limits. The abnormalities could be normal variants, but both need to be investigated with a full workup.

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I would change the plot to:

semilogy(f,p)
axis([0  50    ylim])

Looking closely at the plot, it seems to be relatively ‘clean’ and without significant noise, so the other peaks may be too low amplitude to see easily. Taking the log will probably allow you to see them. You may want to expand the x axis limits in the axis call beyond 50 Hz once you see the semilogy plot.

Best Answer

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