Identification Aspects of Inter

In this contribution aspects of inter sample input signal behavior are examined The starting point is that parametric identi cation always is performed on basis of discrete time data This is valid for identi cation of discrete time models as well as continuous time models The usual assumptions on the input signal are i it is band limited ii it is piecewise constant or iii it is piecewise linear One point made in this paper is that if a discrete time model is used the best possible in the model structure adjustment to data is made This is independent of the assumption on the input signal However a transformation of the obtained discrete model to a continuous one is not possible without additional assumptions on the input signal The other point made is that the frequency functions of the discrete models very well coincides with the frequency functions of the discretized continuous time models and the continuous time transfer function tted in the frequency domain