title: Implementation of a Least mean squares adaptive filter (LMS)
body: <p>Designing an <strong>adaptive filter</strong> (example : LMS filter <a href="http://en.wikipedia.org/wiki/Least_mean_squares_filter" rel="nofollow">http://en.wikipedia.org/wiki/Least_mean_squares_filter</a>) is <em>highly technical</em> and would need high skills in signal processing in order to code such a filter. </p>
  
  <p>Do you think there is somewhere a <em>ready-to-use</em> sourcecode implementation of such a filter?</p>
  
  <p>Example : a simple notch (band reject) filter with a certain fixed frequency ?</p>
  
  <p>I follow here the pilosophy mentionned here (<a href="http://www.mathworks.com/matlabcentral/newsreader/view_thread/14202" rel="nofollow">http://www.mathworks.com/matlabcentral/newsreader/view_thread/14202</a>) :</p>
  
  <blockquote>
    <p>An alternate way of doing this is to use an adaptive LMS approach. The
    narrowest notch will be achieved by adding a sine wave of the same
    amplitude and opposite phase (same frequency)
    to the original waveform. </p>
  </blockquote>