title: phase unwrap issue (the unwrapping of the phases is not correcly)?
body: <p>I have an issue regard to the unwrapping of phases over time.</p>
  
  <p>I have a radar which monitors a slow periodic moving object. From the received signal, i want to see the phase of the object over time. The phase-over-time signal is extracted from FFTs (at the same FFT bin for all the FFTs). Here is the result i got:
  <a href="https://i.stack.imgur.com/dW7lN.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dW7lN.png" alt="enter image description here"></a></p>
  
  <p>Because the phases are wrapped, so I need to do an unwrapping for the phases. I use the Matlab command "<em>unwrap</em>" to to this. So I got: 
  <a href="https://i.stack.imgur.com/XM427.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XM427.png" alt="enter image description here"></a></p>
  
  <p>The issue is marked at the red circle. Here I expect the signal at this time-instant to be unwrapped. However it wasn't, and the reason is:</p>
  
  <pre><code>- From time sample NO. 42 -&gt; 44, the phases take two time samples to being
  wrapped, instead of only one (i.e between two consecutive time samples).
  Because of this the phase-over-time signal are not unwrapped correctly. 
  </code></pre>
  
  <p>I also tried to used another phase-unwrapping method (Adaptive numerical integration), however the result is the same as using "<em>unwrap</em>" command from Matlab.</p>
  
  <p>Here is the phase-over-time signal I expected to see (I did the unwrapping manually):
  <a href="https://i.stack.imgur.com/uuRJE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uuRJE.png" alt="enter image description here"></a></p>
  
  <p>What is the problem mentioned above (Is it a well-known problem or has any name for it)? And of course what is the solution for this?</p>
  
  <p>I would really appreciate any help from you! Thanks alot.</p>