function Cxy=coherence(x,y,L,over,win);
%COHERENCE	Coherence estimation using Welch's method.
%----
%USAGE	Cxy = coherence(x,y,L,over,win)
%
%	The coherence of a process x and y is estimated using Welch's method
%	of averaging modified periodograms.
%
%	x   : input sequence
%  y   : input sequence
%	L   : section length 
%	over: amount of overlap, where 0<over<1, 
%	win : The window type 
%       	1 = Rectangular
%		2 = Hamming
%		3 = Hanning
%		4 = Bartlett
%		5 = Blackman
%
%	Coherence spectrum is returned in Cxy 
%	using a linear scale.
%
if (nargin <= 3) win=1; end;
if (nargin <= 2) over=0; end;
if (nargin == 1) L=length(x); end
if (over >= 1) | (over < 0)  
   error('Overlap is invalid'), end

Sxy=crosswelch(x,y,L,over,win);
Sx=welch(x,L,over,win);
Sy=welch(y,L,over,win);
Cxy=abs(Sxy).^2./(Sx.*Sy);