What are stochastic filtering and stochastic resonance?
Lomonosov Moscow State University, Department of Physics, Vorobevy gory, Moscow, 119992, Russian Federation
The concept of stochastic resonance (SR) was introduced in 1981 in the study of ice-age periodicity in the northern hemisphere. To describe this phenomenon, a relaxation model — an overdamped bistable oscillator — is used. SR is caused by the simultaneous action of a periodic signal and noise and appears as a nonmonotone response to noise intensity variations. Since the subject of the study is actually the filter passband width as a function of noise intensity, ’stochastic filtering’ (SF) seems to be a more appropriate term to describe the phenomenon. It is shown that when driven by a signal and noise, a low-attenuation bistable oscillator also displays ordinary SR when the signal frequency coincides with the effective noise-intensity-dependent frequency of the oscillator. Thus the possibility of the resonance being controlled by varying the noise intensity arises.