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function [hst]=fsfir(hd,flag)
//<hst>=fsfir(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 the chosen grid of frequencies
//!
//author: G. Le Vey Date: 1 Febr. 1989
// Copyright INRIA
n1=prod(size(hd));//filter length
if flag==1 then
hst=hd(1)*dirich(n,0,flag);
for j=1:n1-1,if hd(j+1)<>0,..
hst=hst+hd(j+1)*(dirich(n,j,flag)+dirich(n,-j,flag));end;end
else
if n1==n/2 then
hst=hd(1)*(dirich(n,.5,1)+dirich(n,-.5,1));
for j=2:n1,if hd(j)<>0,..
hst=hst+hd(j)*(dirich(n,j-1,flag)+dirich(n,-j+1,flag));end;end
else
hst=hd(n1)*dirich(n,0,1);
hst=hst+hd(1)*(dirich(n,.5,1)+dirich(n,-.5,1));
for j=2:n1-1,if hd(j)<>0,..
hst=hst+hd(j)*(dirich(n,j-1,flag)+dirich(n,-j+1,flag));end;end
end
end
function [bidon]=dirich(n,p,q)
bidon=0.5;
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