Frequency-locking in coupled chaotic systems

A novel approach is presented for measuring the phase synchronization (freq uency-locking) of coupled N nonidentical oscillators, which can characteriz e frequency-locking for chaotic systems without well-defined phase by measu ring the mean frequency. Numerical simulations confirm the existence off fr equency-locking. The relations between the mean frequency and the coupling strength and the frequency mismatch are given. For the coupled hyperchaotic systems, the frequency-locking can be better characterized by more than on e mean frequency curves.