Simplification of z-transfer function via Padé approximation of tangent phase function

Simplification of
z
-transfer function is performed in the bilinear-transformed domain via approximating tangent phase function by a Padé technique. A modification has been given to the transformed transfer function so that the reduced
z
-transfer function has the same zero initial responses as the original system. The simplified
z
-transfer function is always stable and minimum phase.