Abstract
Considering information associated with the power spectrum characteristics of a system (2nd-order information) as well as information associated with its transfer characteristics (1st-order information), a better outcome is obtained in the field of the system approximation and reduction. In this paper, we discuss the problem of finding discrete-time systems such that its transfer function and the causal part of its power spectrum function have the desired Taylor expansion coefficients, respectively, about the given complex frequency points. Such systems are called system interpolating 1st-and 2nd-order information. We present a parametrization of all such systems, which turns out to be a generalization of some known results. Our result provides a method for the system approximation and reduction which can meet various specifications of frequency characteristics.
