GIUSEPPE GRASSI
Corresponding author.
Dipartimento di Ingegneria dell'Innovazione, Università di Lecce, 73100 Lecce, Italy
SAVERIO MASCOLO
Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, 70125 Bari, Italy

Received 19 February 1999
Revised 4 December 2000

In this Letter a systematic procedure for synchronizing different classes of hyperchaotic systems is illustrated. The approach can be applied to dynamic systems with one or more nonlinear elements as well as to time delay systems. The method is rigorous and systematic. Namely, if a structural property related to the drive system is satisfied, it is easy to design the synchronizing signal and the response system, which is chosen in the observer form. The technique is successfully applied to a recent example of 8th order circuit, to a cell equation in delayed Cellular Neural Networks and to an example of high dimensional system, which consists of five identical coupled Chua's circuits forming a ring. Simulation results are reported to show the performances of the technique.