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How to extract phase and amplitude information from FFT?

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Mayank Lakhani
Mayank Lakhani el 26 de Jun. de 2015
Comentada: Adam el 14 de Jul. de 2017
I am doing signal processing of radar data. I applied butturworth bandpass filter and applied fft to the radar data.I want to know how to extract the phase and amplitude information of radar data so i can add it to my ideal radar simualation and make it non ideal :D . Thanks
load('fb2040'); % loading the data
x = fb2040(3,:);
y_filt = filter(b,a,x); % filtering the received signal
nfft = length(y_filt);
res = fft(y_filt,nfft)/ nfft; % normalizing the fft
f = fs/2*linspace(0,1,nfft/2+1); % choosing correct frequency axes
res = res(1:nfft/2+1);
figure, plot(f,abs(res));
xlabel('Frequency in MHz');ylabel('Amplitude');
return

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Adam
Adam el 26 de Jun. de 2015
If you want the phase and amplitude for different frequencies then these are just:
angle( res );
real( res );
or
abs( res );
if you want the magnitude rather than amplitude.
  2 comentarios
Peter Mbamaluikem
Peter Mbamaluikem el 13 de Jul. de 2017
Hi, Adam what if there are several frequencies and one is to extract the magnitude of one say 60Hz. what will the code be?
Adam
Adam el 14 de Jul. de 2017
'res' in the above code is a vector of results corresponding to the frequencies in 'f' in the original code in the question so just find the 'f' that is closest to 60Hz and take the magnitude of that value rather than the whole vector.

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