System identification with multi-level periodic perturbation signals

Multi-level periodic perturbation signals for system identification in the frequency domain are defined. The design and properties of these signals, and the output signal processing methods used with them to reduce or eliminate the effects of noise and nonlinearity, are developed. Both pseudo-random and multi-frequency perturbation signals are considered, and an application in which these signals were used to identify the dynamics of steel strip in an industrial process is described. It is concluded that the use of these signals leads to considerable benefits, and that they are to be preferred for identification schemes of this kind. (C) 1999 Elsevier Science Ltd. All rights reserved.