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////////////////////////
//MINIMAX FIR FILTERS///
////////////////////////
// Copyright INRIA
xbasc();xselect();
//Low pass filter (length 33, cut-off in [.23,.27], weight 1/.1)
hn=eqfir(33,[0 .23;.27 .5],[1 0],[1 .1]);
[hm,fr]=frmag(hn,256);
plot2d(fr',hm'),
title_c=['Minimax FIR filter';
'low pass cut-off in [.23,.27]';
'length 33'];
xtitle(title_c);
halt(),xbasc();
//Triangular filter created using remezb
nc=21;
ngrid=nc*16;
fg=.5*(0:(ngrid-1))/(ngrid-1);
ds(1:ngrid/2)=(0:-1+ngrid/2)*2/(ngrid-2);
ds(ngrid/2+1:ngrid)=ds(ngrid/2:-1:1);
wt=ones(fg);
[an]=remezb(nc,fg,ds,wt);
hn(1:nc-1)=an(nc:-1:2)/2;
hn(nc)=an(1);
hn(nc+1:2*nc-1)=an(2:nc)/2;
[hm,fr]=frmag(hn,maxi(size(ds)));
plot2d(fr',hm'),
xtitle('Remez Triangular filter','frequency','magnitude');
halt();xbasc();
plot2d(fr',(hm-ds)'),
xtitle(' ','frequency','magnitude error');
halt(),xbasc();
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