title: Implement Hann Window
body: <p>I take blocks of incoming data and pass them through fftw to get some spectral information. Everything seems to be working, however I think I'm getting some aliasing issues.</p>
  
  <p>I've been trying to work out how to implement a hann window on my blocks of data. Google has failed me for examples. Any ideas or links I should be looking at?</p>
  
  <pre><code>double dataIn[2048] &gt; /* windowing here? */ &gt; FFT &gt; double freqBins[2048]
  </code></pre>
  
  <p><strong>Update</strong></p>
  
  <p>Thanks to Oli for pointing out the issue I'm actually trying to fix is spectral-leakage, NOT aliasing...</p>