[scilab-Users] Cascaded IIR filter design

[Adelson Santos de Oliveira]

Do you mean,

coef_hz=coeff(hz) ?

coef_hz is a vector with the coefficients of hz.

coefhz=coeff
Markus Svilans escreveu:
> Hello,
>
> I would like to use Scilab to design a cascaded IIR filter.
>
> I'm able to design a filter using iir(), as in the following example
> code:
>
> ystr=[ 'type (lp, hp, bp, sb) ';
>    'order (integer)';
>    'design (butt, cheb1, cheb2 , ellip)' ;
>    'cut-off frequencies (2-vector in [0, 0.5])';
>    'error values  0 delta(1),delta(2) 1 '];
> w = x_mdialog('Choose filter type and parameters',...
>    ystr,['bp';'3';'ellip';'0.15 0.25';'0.08 0.035'])
>
> if w<>[] then
>  hz=iir(evstr(w(2)),w(1),w(3),evstr(w(4)),evstr(w(5)));
>  [hzm,fr]=frmag(hz,256);
>  xselect();
>  plot2d(fr',hzm')
>  xtitle('Discrete IIR filter '+'( '+ w(3)+' ) ',' ',' ');
>
>  hz
> end
>
> My question is, how can I convert the z domain expression in hz to a
> set of coefficients suitable for use in a cascaded IIR filter
> implementation? Any help would be greatly appreciated.
>
> Best regards,
> Markus.
>
> (also posted in the comp.soft-sys.math.scilab group)
>
>