Deterministic identification of linear dynamic systems

This paper considers the problem of identifying multiinput single-output linear time-invariant discrete-time systems from noise-free input/output measurements. The effect or input on identification is studied in detail. It is shown that the correctness associated with an identification is critically dependent on the input sequence used. Furthermore, as long as only finite input/output sequences are used for identification, there is always a possibility that the actual system is of higher order than the identified models reveal This uncertainty leads to the concept of tentative identification. Sufficient conditions for correct order determination and modeling are also investigated.