bilt

bilinear or biquadratic transform SISO system given by a zero/poles representation

Calling Sequence

[npl,nzr,ngn] = bilt(pl,zr,gn,num,den)

Arguments

:pl a vector, the poles of the given system. : :zr a vector, the zeros of the given system. : :num a polynomial with degree equal to the degree of den, the

numerator of the transform.

: :den a polynomial with degree 1 or 2, the denominator of the

transform.

: :npl a vector, the poles of the transformed system. : :nzr a vector, the zeros of the transformed system. : :ngn a scalar, the gain of the transformed system. :

Description

function for calculating the gain poles and zeros which result from a bilinear transform or from a biquadratic transform. Used by the functions iir and trans.

Examples

Hlp=`iir`_(3,'lp','ellip',[0.1 0],[.08 .03]);
pl=`roots`_(Hlp.den);
zr=`roots`_(Hlp.num);
gn=`coeff`_(Hlp.num,`degree`_(Hlp.num))/`coeff`_(Hlp.den,`degree`_(Hlp.den));
z=`poly`_(0,'z');
a=0.3;
num=z-a;
den=1-a*z;
[npl,nzr,ngn] = bilt(pl,zr,gn,num,den)

Hlpt=ngn*`poly`_(nzr,'z','r')/`poly`_(npl,'z','r')

//comparison with horner
`horner`_(Hlp,num/den)

See Also

• iir iir digital filter
• trans low-pass to other filter transform
• horner polynomial/rational evaluation