A Note on Spectral Conditions for Positive Realness of Transfer Function Matrices
Robert Noel Shorten, PAUL F. CURRAN, Kai Wulff, E. Zeheb · IEEE Transactions on Automatic Control · 2008
Necessary and sufficient conditions for Positive Realness of general transfer function matrices are derived. The conditions are expressed in terms of eigenvalues of matrix functions of the state matrices representation of the LTI system. Illustrative numerical examples are provided.