function [w,t]=ormsby(f1,f2,f3,f4,tlen,dt)

% [w,t]=ormsby(f1,f2,f3,f4,tlen,dt)
%
% Make a ormsby wavelet given the four frequency parameters
% f1 = low frequency stop
% f2 = lowest frequency to pass unattenuated
% f3 = highest frequency to pass attenuated`
% f4 = high frequency stop
% tlen = wavelet length in seconds. Wavelet will go from
%	-tlen/2 to tlen/2
% dt = wavelet sample rate in seconds
% NOTE: It is illegal for you to use this software for a purpose other
% than non-profit education or research UNLESS you are employed by a CREWES
% Project sponsor. By using this software, you are agreeing to the terms
% detailed in this software's Matlab source file.
 
% BEGIN TERMS OF USE LICENSE
%
% This SOFTWARE is maintained by the CREWES Project at the Department
% of Geology and Geophysics of the University of Calgary, Calgary,
% Alberta, Canada.  The copyright and ownership is jointly held by 
% its author (identified above) and the CREWES Project.  The CREWES 
% project may be contacted via email at:  crewesinfo@crewes.org
% 
% The term 'SOFTWARE' refers to the Matlab source code, translations to
% any other computer language, or object code
%
% Terms of use of this SOFTWARE
%
% 1) Use of this SOFTWARE by any for-profit commercial organization is
%    expressly forbidden unless said organization is a CREWES Project
%    Sponsor.
%
% 2) A CREWES Project sponsor may use this SOFTWARE under the terms of the 
%    CREWES Project Sponsorship agreement.
%
% 3) A student or employee of a non-profit educational institution may 
%    use this SOFTWARE subject to the following terms and conditions:
%    - this SOFTWARE is for teaching or research purposes only.
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%      software that will be resold is expressly forbidden.
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% END TERMS OF USE LICENSE

% make the time coordinate vector`
	t=-tlen/2:dt:tlen/2;

%make the wavelet
	w= (pi*f4)^2 * (sinque(pi*f4*t)).^2/(pi*f4-pi*f3);
	w= w- (pi*f3)^2 * (sinque(pi*f3*t)).^2/(pi*f4-pi*f3);
	w= w- (pi*f2)^2 * (sinque(pi*f2*t)).^2/(pi*f2-pi*f1);
	w= w+ (pi*f1)^2 * (sinque(pi*f1*t)).^2/(pi*f2-pi*f1);