How can I correct this error?

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))');

[Stephan]

Hi,

your question is a little bit unclear. What is the problem?

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.') 
xlabel('time (s)');
ylabel('Acceleration (ms^(-2))');

The actual code gives you a blue line with the acc over tmp values and additionally red dots from also acc over tmp. Do you want to show disp over tmp instead? Or does your curve not look like it should?

There was just one mistake in

xlable('time (s)');

which should be

xlabel('time (s)');

Please tell your problem a little more exactly. If possible attach data1 file.

Best regards

Stephan

[Mallouli Marwa]

Hi

See Data1 as attached.

I want also to show disp over tmp instead

Thanks for help

Answer 1

[Stephan]

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

[Mallouli Marwa]

Thanks

[Mallouli Marwa]

I have added this part in the program that calculate the Fourier

Transform of the voltage but the trend is not well.

The curve FRF wanted attached is the best trend.

So How can I ameloirate the trend of this FRF found (figure3 in the program).

The program is:

%% %script traitement signal %objet : traitement signal MPF clc; clear; close all; cd Z:\Matlam\Curves_oscillo_Pc %%

%% load 'data1.txt';

tmp = data1(:,1);

disp = data1(:,2);

acc = data1(:,3);

figure(1)

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

xlabel('time (sec)');

ylabel('Acc (ms^{-2})');

%on récupère les données de Oscilloscope en Volt

load 'data1V.txt';

tmpV = data1V(:,1);

Volt = data1V(:,2);

%Voltb = 40e-3*ones(size(tmpV));

figure(2)

plot(tmpV,Volt,'b',tmpV,Volt,'r.');

xlabel('time (sec)');

ylabel('Voltage(V)'); %%

L=length(tmp)

Lv=length(tmpV)

Fs = 5000; % Sampling frequency

NFFT = 2^nextpow2(L) % Next power of 2 from length of y

NFFTV = 2^nextpow2(Lv) % Next power of 2 from length of y

figure(3)

VOLT = fft(Volt,NFFT)/L; % Calcul de la FFT

amplitude = 2*abs(VOLT(1:NFFT));

f = Fs/2*linspace(0,1,NFFT/2);

semilogy(f(1:NFFT/12),2*abs(VOLT(1:NFFT/12)))

xlabel('frequency')

ylabel('FRF Volatage')