NONLINEAR AMPLIFICATION EFFECTS IN A PERIOD-DOUBLING SERIES RESONANCE CIRCUIT

Abstract

The influence of small near-resonant perturbations on the period-doubling bifurcations in a nonlinear series resonance circuit has been investigated in detail. The series resonance circuit contains ferroelectric triglycine sulfate (TGS) as nonlinear capacitor. If the temperature of the TGS-crystal is below the Curie-temperature this dynamical system is a good experimental realization of a Duffing-like oscillator with double-well potential. The depth of the double-well potential may be changed easily by temperature variation of the TGS-crystal. Variation of the amplitude of the driving voltage in the order of magnitude of the coercive field strength and the frequency of the driving voltage in the range of domain relaxation can be used to tune the system towards period-doubling bifurcations. An additional near-resonant perturbation has been introduced into the system by amplitude modulation of the driving voltage. The observed effects (small signal amplification, shift of the bifurcation point, multiple-side peaks around odd harmonics of half the driving frequency) are compared to theoretically derived results. They are well understood on the basis of the center manifold analysis taking into account nonlinear effects in the normal form of the period-doubling bifurcation.