Hello everyone,
a short question about the calculation of the PSD using the FFT. I used the example code provided:
rng defaultFs = 1000;t = 0:1/Fs:1-1/Fs;x = cos(2*pi*100*t) + randn(size(t));N = length(x);xdft = fft(x);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;
I understand each step except this one:
psdx(2:end-1) = 2*psdx(2:end-1);
Why do we double entry except the first and the last? Is it about the symmetry of the FFT?
Thanks ahead and best regards, Chris
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