A low-order modelling method for Z-domain transfer functions

Abstract

When digital computer-based parameter estimation techniques are used to identify linear, dynamic systems, the results are usually obtained in the form of a high order Z-domain transfer function. For many practical applications, however, a model transfer function of second or third order is sufficient to represent the prominent features of the system dynamics. A computationally simple transfer function reduction method, based on the Matsuburu time delay theorem, is presented herein. This method is compared with a recently reported Padé approximation approach in both the time and frequency domains.