U-SEQUENCE AND PERIOD-TRIPLING PHENOMENA IN A FORCED NONLINEAR CSCILLATOR

Experiments on a nonlinear oscillator reveal the same periodic structure as that in one-dimensional unimodal maps and a simple method is found to assign words from a symbolic dynamics of two letters to the periods observed in experiments. This paper gives plentiful patterns of U-sequence, including period-tripling patterns R*RL, RL*RL and RL²*RL. Spectral analysis gives a confirmation of the patterns.