On computing the l/sub 1/ norm of a polynomial matrix fraction

This paper proposes a new algorithm for computing the l/sub 1/ norm of a linear MIMO system described by a polynomial matrix fraction. The algorithm follows the one proposed by Balakrishnan and Boyd (1992) with the only difference that there is no need to obtain a state space realization first. Instead, the coefficients of the polynomial matrices are used directly. The algorithm is based on two computational steps: an FFT-based long division of polynomial matrices and the polynomial computation of Hankel singular values presented by Kwakernaak (1992).