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// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA - 1989 - G. Le Vey
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution. The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
function [hst]=fsfirlin(hd,flag)
//<hst>=fsfirlin(hd,flag)
//macro for the design of FIR, linear phase filters
//using the frequency sampling technique
// hd : vector of desired frequency response samples
// flag : is equal to 1 or 2,
// according to the choice of type 1 or type 2 design
// hst : vector giving the approximated continuous response
// on a dense grid of frequencies
//!
n1=prod(size(hd));//filter length
if int(n1/2)==n1/2,n=2*n1;else,n=2*n1+1;end;//even or odd length
scd=sincd(n,flag);//calculates the function Sin(N*x)/Sin(x)
hst=hd(1)*scd(4*n+1:6*n+1);
eps=(-1)**(n-1);
for j=1:n1-1,hst=hst+hd(j+1)*[scd(-4*j+4*n+1:-4*j+6*n+1)+..
eps*scd(4*j+1:4*j+2*n+1)];end;
endfunction
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