# build_SS_poly

Builds a discrete-time state-space representation of a polynomial system whose frequency response has from:

Ypoly[oo,ii](k) = -A2[oo,ii] D2(k) - A1[oo,ii] D1(k) - A0[oo,ii]

where C1,D2 are discrete-time models of first and second derivatives, ds is the time-step and the coefficient matrices are such that:

A{nn}=Acf[oo,ii,nn]