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function demo_signal()
demo_help demo_signal
SetPosition();
set figure_style old; //xselect();xbasc();
//xset("wpos",500,16);xset("wdim",500*0.9,350*0.9);
//xset('wpos',620,16);xset('wdim',600,540);
subplot(221)
hz=iir(3,'bp','ellip',[0.15 0.25],[0.08 0.035]);
[hzm,fr]=frmag(hz,256);
plot2d(fr',hzm')
xset("font size",3) ;
xtitle('Discrete elliptic IIR filter',' ',' ');
subplot(222)
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);
subplot(223)
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');
subplot(224)
[wft,wfm,fr]=wfir('lp',33,[.2 0],'kr',[5.6 0]);
plot2d(fr',log(wfm)')
xtitle(' ','frequency','magnitude');
xtitle(['Windowed FIR Low pass Filter';...
'Kaiser window,cut-off:0.2';...
'length 33'])
realtimeinit(0.1),for k=1:60,realtime(k),end
xdel()
endfunction
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