iirpowcomp
Power complementary IIR filter
Syntax
[bp,ap] = iirpowcomp(b,a)
[bp,ap] = iirpowcomp(b,a,c)
Description
[bp,ap] = iirpowcomp(b,a) returns
the coefficients of the power complementary IIR filter g(z)
= bp(z)/ap(z)
in vectors bp and ap, given
the coefficients of the IIR filter h(z) = b(z)/a(z) in vectors b and a. b must
be symmetric (Hermitian) or antisymmetric (antihermitian) and of the
same length as a. The two power complementary filters
satisfy the relation
|H(w)|2 + |G(w)|2 = 1.
[bp,ap] = iirpowcomp(b,a,c) where c is
a complex scalar of unity magnitude, forces bp to
satisfy the generalized hermitian property:
conj(bp(end:-1:1)) = c*bp.
When c is omitted, the function chooses c as
follows:
When
bis real, the function choosescas 1 or -1, whichever yieldsbpas real.When
bis complex,cdefaults to 1.
ap is always equal to a.
Examples
Power Complementary IIR Filter
[b,a]=cheby1(10,.5,.4); [bp,ap]=iirpowcomp(b,a); fvtool(b,a,bp,ap,'MagnitudeDisplay','Magnitude squared'); legend('Original Filter','Power Complementary Version');
