Experimental study of high frequency stochastic resonance in Chua circuits

We study the stochastic resonance phenomenon occurring in electronic Chua circuits operating in the chaotic regime when the forcing signal is modulated at relatively high frequency, of the order of magnitude of the main Chua frequency in the absence of forcing ($f_o$). In all the cases, a clear maximum in the signal-to-noise ratio for an intermediate noise level is observed. When modulating with a frequency smaller than $f_o$ we also observe a resonance at a harmonic of the external frequency which is closer to $f_o$ or to one of its harmonic. If the modulating frequency is larger than $f_o$ we only observe the resonance at the modulating frequency.