Noise-Induced FM Demodulation and Nonlinear Dynamics in a PLL Circuit

Nonlinear dynamics and the effect of noise on the dynamics in the FM (Frequency Modulation) demodulator were investigated. The FM demodulator concerned here is composed of the phase-locked loop. Various nonlinear responses including chaos were observed. It was also found that an adequately demodulated output was recovered from a turbulent state by applying noise to the FM input. The obtained correlation curve exhibited a peak around a certain value of the power of the applied noise. This phenomenon was apparently similar to what is called the stochastic resonance observed in various kinds of nonlinear systems