Locking threshold as a stochasticity criterion in an oscillator with inertial nonlinearity

The locking threshold is used as a criterion in the experimental study of chaos in an oscillator with inertial nonlinearity and a parametric external influence modulating the active element gain. Results are presented of a study of the transition to chaotic amplitude modulation upon an increase in the depth of the parametric influence at frequencies equal to 2-4 kHz. It is found that, near the boundary of the transition to chaos, the curve of the amplitude threshold for locking has the same character as that of the maximum Lyapunov exponent. It is concluded that the locking threshold can serve as a convenient and informative characteristic of chaotic motion in dynamical systems.