Convert zero-pole-gain filter parameters to state-space form
[A,B,C,D] = zp2ss(z,p,k)
zp2ss converts a zero-pole-gain representation of a given system to an equivalent state-space representation.
given a system in factored transfer function form.
Column vector p specifies the pole locations, and matrix z the zero locations with as many columns as there are outputs. The gains for each numerator transfer function are in vector k. The A, B, C, and D matrices are returned in controller canonical form.
Inf values may be used as place holders in z if some columns have fewer zeros than others.