function Dh=dwindow(h);%DWINDOW Derive a window.%	DH=DWINDOW(H) derives a window H.%%	Example : %	 plot(dwindow(tftb_window(210,'hanning')))%%	See also WINDOW.%	F. Auger, August 1994, July 1995.%	Copyright (c) 1996 by CNRS (France).%%	------------------- 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), error('one parameter required'); end;[hrow,hcol]=size(h); if (hcol~=1), error('h must have only one column');end;Lh=(hrow-1)/2;step_height=(h(1)+h(hrow))/2;ramp=(h(hrow)-h(1))/(hrow-1);h2=[0;h-step_height-ramp*(-Lh:Lh).';0]; Dh=(h2(3:hrow+2)-h2(1:hrow))/2 + ramp; Dh(1)   =Dh(1)   +step_height; Dh(hrow)=Dh(hrow)-step_height;