Comment on `Minimal realisation algorithm for impulse response matrix using modified moments´

In their letter, Eydgahi and Singh (see ibid., vol.20, p.742-3, 1984) presented a procedure for the minimal realisation of an impulse response matrix of a linear time-invariant system based on modified moments which are simply connected to the coefficients of the Taylor series expansion of the system transfer function about a general point. The commentator shows that the modified moments, also useful in system identification and model reduction, can be measured directly by using shape-designed measuring signals. The signals may be designed by the generalised mirror reflection (GMR) method given. The method concerns linear systems which can be represented by a set of linear functionals