title: Fourier Transform on varied time data
body: <p>So... no clue where I should be asking this question but I'm hoping someone here can at least point me in the right direction. I have a time series that I would like to do spectral analysis on but I can't find any tools for doing FFT that accommodate a varied time difference between data points (they all assume dt is constant). Does anyone know of a tool that would work for this (I'm specifically looking for a periodogram or some other way to determine periodicity).</p>
  
  <p>My only thought is to do linear interpolation between data points at a specific time interval to give the data a constant dt but I'm worried that will scew the spectral analysis data.</p>
  
  <p>Here is a small chunk of the data; time, data, dt</p>
  
  <pre><code> time    data        dt
  39.630  49662.1     0.170
  39.810  49582.5     0.180
  40.150  49430.0     0.340
  40.320  49413.8     0.170
  40.490  49324.0     0.170
  40.670  49092.5     0.180
  40.830  49025.6     0.160
  41.010  49101.5     0.180
  </code></pre>
  
  <p>any suggestions??</p>