SINCRONIZAÇÃO E MEMÓRIAS EM OSCILADORES COLPITTS ACOPLADOS

Abstract

We focus on the study of Colpitts oscillators. We have chosen this circuit due to the fact that it can be useful in applications to communication systems, as well as, it exhibits a rich dynamical behaviour for certain parameter values. In the Colpitts oscillator the operation frequency can vary from few Hertz up to the microwave frequency range, a characteristic that enables the use of this circuit to transmit information in channels with diferent frequency bandwidths. This thesis has two parts: (i) super persistent transient in a master-slave configuration with Colpitts oscillators, and (ii) short-time memories in coupled Colpitts. We considered Colpitts oscillators coupled according to a master-slave configuration to study chaos synchronisation. We revealed the existence of super persistent transients in this coupled system. Moreover, we showed that an additive noise in the slave system may suppress chaos synchronisation. When synchronisation is not suppressed, the noise induces longer transients. Moreover, we considered a network of coupled circuits, Colpitts oscillators, and we investigated memory storage with an external input. The memories were defined in terms of the diferences among the electrical currents amplitudes. We showed the existence of multiple memories, which enables us to use these systems to encode signals.