How can i take the FFT of this signal. Please any one can help me.

CORR=(X(:,1)-mean(X(:,1)))/g; %Shift of signal to zero value
%Plot Corrected signal in Time Domain
figure(3)
plot(t,CORR);
title('Corrected signal in Time Domain');
xlabel('Time [s]');
ylabel('Acceleration [cm/s^2]');

[Image Analyst]

You forgot to attach X and g. But I assume you know about the fft() function, yet you are not showing code where you called it. Why not?

[DRISHYA S KUMAR P N]

X=xlsread('sujith.xlsx');
disp(X);
g=981; %gravity acceleration [cm/s^2]


I already mentioned X and g

[DRISHYA S KUMAR P N]

I am getting this error

Error using fft

FFT length must be a nonnegative integer scalar.

Error in Accelerometer(line 34)

xdft=fft(t,CORR);

my code is:

N=length(X);
xdft=fft(t,CORR);
xdft=xdft(1:N/2+1);
psdx=(1/(Fs*N))*abs(xdft).^2;
psdx(2:end-1)=2*psdx(2:end-1);
freq=0:Fs/length(X):Fs/2;
figure(4)
plot(freq,10*log10(psdx))
grid on
title('FFT')
xlabel('Frequency (HZ)')
ylabel('Amplitude')

can you please help me sir.
Thank you

[Divija Aleti]

Can you attach the excel sheet 'sujith.xlsx' along with your entire code so we can understand better ?

[Mathieu NOE]

Hi

I think it's just because there is an error in your code :

xdft=fft(t,CORR);

to be replaced by

xdft=fft(CORR,N);