Stochastic resonance, found in many natural and engineered bistable systems, refers to a physical phenomenon wherein the response of nonlinear dynamical systems to weak input signal is enhanced by the presence of noise, tuned to the optimal level. However, the observation of this phenomenon for weak subthreshold periodic magnetic field signals in chaotic bistable systems has not been reported. In this paper we present the experimental observation of stochastic resonance in a Chua circuit. The experiment was performed using an internal Gaussian noise source, and an external driving subthreshold sinusoidal magnetic field below 1mT, with a frequency range in the order of kHz. The circuit was operating near the switching threshold between single-scroll and double-scroll chaotic regimes. The spectral characteristics of interest (the output signal power at forcing signal frequency and the signal-to-noise ratio) pass through a maximum with varying noise intensity. The residence times probability distribution quantifying the synchronization between the forcing and the response has a multi-peaked structure for the optimal noise intensity. Our experiments show the possibility of stochastic resonance for weak subthreshold magnetic field signals in chaotic systems, with parts of the attractor located in different regions of the phase space and with internal noise.

在许多自然和工程双稳态系统中发现的随机共振是指一种物理现象，其中，通过将噪声调整到最佳水平，噪声的存在会增强非线性动力系统对弱输入信号的响应。但是，尚未报道在混沌双稳态系统中对弱亚阈值周期性磁场信号观察到这种现象。在本文中，我们介绍了蔡氏电路中随机共振的实验观察。实验是使用内部高斯噪声源和低于1mT的外部驱动亚阈值正弦磁场进行的，频率范围为kHz量级。电路在单滚动和双滚动混沌状态之间的切换阈值附近工作。感兴趣的频谱特性（在强制信号频率和信噪​​比下的输出信号功率）会随着噪声强度的变化而通过最大值。量化强迫与响应之间的同步的停留时间概率分布具有用于最佳噪声强度的多峰结构。我们的实验表明，在混沌系统中弱亚阈值磁场信号可能发生随机共振，其中部分吸引子位于相空间的不同区域，并且内部存在噪声。量化强迫与响应之间的同步的停留时间概率分布具有用于最佳噪声强度的多峰结构。我们的实验表明，在混沌系统中弱亚阈值磁场信号可能发生随机共振，其中部分吸引子位于相空间的不同区域，并且内部存在噪声。量化强迫与响应之间的同步的停留时间概率分布具有用于最佳噪声强度的多峰结构。我们的实验表明，在混沌系统中弱亚阈值磁场信号可能发生随机共振，其中部分吸引子位于相空间的不同区域，并且内部存在噪声。