title: How to generate noise in frequency range with numpy?
body: <p>I have a main signal, for example sinus with period of 200 samples. </p>
  
  <p>I would like to add a noise to this signal. The periods of "noise signal parts" should be in range for example 5-30 samples.</p>
  
  <p>I thought that will be enough to generate multiple sinuses in this range with different randomly chosen amplitudes:</p>
  
  <pre><code>noise = np.sin(np.array(range(N))/0.7)*np.random.random(1) + np.sin(np.array(range(N))/1.1)*np.random.random(1) + np.sin(np.array(range(N))/1.5)*np.random.random(1) 
  </code></pre>
  
  <p>But this solution is still too much "deterministic" for my purpose.</p>
  
  <p>How could I generate noise with randomly changing amplitude and period?</p>