Comments on "A modification and the Tustin approximation" with a concluding proposition

In the original paper (K.B. Janiszowski, ibid., vol. 38, no. 8, p. 1313-16, 1993) there is presented a modification of the Tustin approximation. The author argues that the justification of this modification, by means of three examples, is not convincing, because the choice of the examples is questionable and some calculations are not sufficiently accurate. It is shown that some good properties of the proposed modification can be justified by using the Tustin approximation of a continuous-time (CT) model for the discrete-time (DT) system. It is stressed that the proposed modification has only a limited value, since from application point of view the use of CT models is more reasonable. As the conclusion the DT controller design procedure by using CT methods is proposed.<
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