Matched pole-zero discrete-time models

The previously proposed concept (Hori, Mori, and Nikiforuk, 1989) of classifying various discrete-time models, such as invariant and mapping models is extended to matched pole-zero models. In the existing matched pole-zero methods, the gain adjustment of the discrete-time model is required and the addition of extra zeros is often suggested in the literature. In the newly proposed method, there is no need for such adjustments. A simple example is provided to show this point and to explain why the existing models need these adjustments.