A characteristic is suggested for the evaluation of the degree of synchroni
zation of the chaotic oscillations in a system of two coupled oscillators.
The proposed value is tested by application to the case of two unidirection
ally coupled logistic maps. It is shown that this characteristic is stable
with respect to a low noise and a nonlinear distortion of the signal. (C) 2
001 MAIK "Nauka/Interperiodica".