function  h = mexhat(nu) ;%MEXHAT	Mexican hat wavelet in time domain.%	H=MEXHAT(NU) returns the mexican hat wavelet with central %	frequency NU (NU is a normalized frequency in Hz). %%	NU : any real between 0 and 0.5		(default : 0.05).%	H  : time vector containing the mexhat samples. %		length(H)=2*ceil(1.5/NU)+1.%%	Example : %	 plot(mexhat);%%	See also KLAUDER.%	P. Goncalves, October 95%	Copyright (c) 1995 Rice University%%	------------------- CONFIDENTIAL PROGRAM -------------------- %	This program can not be used without the authorization of its%	author(s). For any comment or bug report, please send e-mail to %	f.auger@ieee.org if nargin==0, nu=0.05;elseif nargin>1, error('Too many input parameters');endif nu>0.5 | nu<0, disp('Warning : NU should be between 0 and 0.5');endN = 1.5 ;alpha = pi^2*nu^2 ;n = ceil(N/nu) ; t = -n:n ;h = nu*sqrt(pi)/2*exp(-alpha*t.^2).*(1-2*alpha*t.^2) ;