Abstract: “The paper proposes a mixed method for reducing the order of discrete time interval systems. The numerator and denominator of the reduced order model is obtained by forming table and combining factor division method and Cauer second form. Bilinear transformation (z = p+1) is used during the process of higher order discrete interval systems before applying reduction method. The proposed method shows that it is well suited to reduce both denominator and numerator interval discrete polynomials. The proposed method is compared with the existing methods of discrete interval system reduction. A numerical example has been discussed to illustrate the procedure. Accuracy of the system stability has been verified by using step response.”

Keywords: Cauer second form, discrete interval systems, α table, β table, factor division, mixed method.