title: Fast Fourier Transform (fft) with Time Associated Data Python
body: <p>I have data and a time 'value' associated with it (Tx and X).</p>
  
  <p>How can I perform a fast Fourier transform on my data.</p>
  
  <p>Tx is an array I have and X is another array I have. The length of both arrays are of course the same and they are associated by Tx[i] with X[i] , where i goes from 0 to len(X).</p>
  
  <p>How can I perform a fft on such data to ultimately achieve a Power Spectral Density plot frequency against |fft|^2.</p>