STOCHASTIC RESONANCE WITHOUT EXTERNAL PERIODIC FORCE

A model of a two-dimensional autonomous system subject to external noi se is investigated. Without noise the system has a stable limit cycle in a certain region of control parameter. Various noise-induced effect s have been found numerically, such as a noise-induced frequency shift in the presence of the deterministic limit cycle, and noise-induced c oherent oscillations in the absence of the deterministic limit cycle. An interesting result is that the stochastic resonance phenomenon appe ars in a system without an external signal and when the asymptotic sta te of the deterministic system is stationary.