title: How to get high and low envelope of a signal
body: <p>I have quite a noisy data, and I am trying to work out a high and low envelope to the signal. It is kind of like this example in MATLAB:</p>
  <p><a href="http://uk.mathworks.com/help/signal/examples/signal-smoothing.html" rel="noreferrer">http://uk.mathworks.com/help/signal/examples/signal-smoothing.html</a></p>
  <p>in &quot;Extracting Peak Envelope&quot;. Is there a similar function in Python that can do that? My entire project has been written in Python, worst case scenario I can extract my numpy array and throw it into MATLAB and use that example. But I prefer the look of matplotlib... and really cba doing all of those I/O between MATLAB and Python...</p>
  <p>Thanks,</p>