xy = CMTM(X,Y,NW,Fs) specifies a sampling frequency Fs.

   [Cxy,F] = CMTM(...) also returns the vector of frequencies at which
   the coherence is estimated.  If Fs is specified, this vector ranges
   from [0,Fs/2] and the units are the same as Fs.  If Fs is not
   specified, F ranges from [0,1/2] and the units are relative to the 
   sampling frequency.

   CMTM(...) without output arguments plots the magnitude-squared
   and phase of the coherence (in two subplots) in the current figure.</pre></div>

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