I have a program , a part of which is shown below:
X=x(:,1); %assigning X, all the values of x of length n.
Y = fft(X,n); % calculating the fast fourier transform of X.
T=fft(t,n); %calculating the fast fourier transform of time.
After the execution of the program, I get the spectral plot, but a warning too: Warning: Imaginary parts of complex X and/or Y arguments ignored.
This means imaginary parts has been excluded. I am keen interested in, if I am be able to get the plot which will involve both real and imaginary parts. I will be much thankful, if anyone take interst to clear my problem.
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That is because you want to plot only the magnitude of the DFT coefficients, or the magnitudes squared
I have no idea why you are taking the Fourier transform of your time vector, that is not the frequency vector.
You need to create a meaningful frequency vector by knowing the number of points and the sampling frequency (interval)
t = 0:0.001:1-0.001; %sampling interval is 0.001 Fs = 1000; x = cos(2*pi*100*t)+randn(size(t)); xdft = fft(x); freq = 0:Fs/length(x):Fs/2; xdft = xdft(1:length(x)/2+1); plot(freq,20*log10(abs(xdft)))
Of course in the DFT coefficients, you certainly have the imaginary parts.