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, a nd the output signal processing methods used with them to reduce or elimina te the effects of noise and nonlinearity, are developed. Both pseudo-random and multi-frequency perturbation signals are considered, and an applicatio n 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 thes e signals leads to considerable benefits, and that they are to be preferred for identification schemes of this kind. (C) 1999 Elsevier Science Ltd. Al l rights reserved.