Three-frequency resonances in dynamical systems

We investigate numerically and experimentally dynamical systems having thre e interacting frequencies: a discrete mapping (a circle map), an exactly so lvable model (a system of coupled ordinary differential equations), and an experimental device (an electronic oscillator). We compare the hierarchies of three-frequency resonances we find in each of these systems. All three s how similar qualitative behaviour, suggesting the existence of generic feat ures in the parameter-space organization of three-frequency resonances.