Scilab Function
Last update : 28/12/2008
eqiir - Design of iir filters
Calling Sequence
- [cells,fact,zzeros,zpoles]=eqiir(ftype,approx,om,deltap,deltas)
Parameters
-
ftype: filter type ('lp','hp','sb','bp')
-
approx: design approximation ('butt','cheb1','cheb2','ellip')
-
om: 4-vector of cutoff frequencies (in radians) om=[om1,om2,om3,om4], 0 <= om1 <= om2 <= om3 <= om4 <= pi. When ftype='lp' or 'hp', om3 and om4 are not used and may be set to 0.
-
deltap: ripple in the passband. 0<= deltap <=1
-
deltas: ripple in the stopband. 0<= deltas <=1
-
cells: realization of the filter as second order cells
-
fact: normalization constant
-
zzeros: zeros in the z-domain
-
zpoles: poles in the z-domain
Description
Design of iir filter interface with eqiir (syredi)
The filter obtained is h(z)=fact*product of the elements of
cells.
That is hz=fact*prod(cells(2))./prod(cells(3))
Examples
[cells,fact,zzeros,zpoles]=...
eqiir('lp','ellip',[2*%pi/10,4*%pi/10],0.02,0.001)
transfer=fact*poly(zzeros,'z')/poly(zpoles,'z')
See Also
eqfir, iir,