Resumo

SANCHEZ LOPEZ, C. A 1.7 MHz Chua's circuit using VMs and CF+s. Rev. mex. fis. [online]. 2012, vol.58, n.1, pp.86-93. ISSN 0035-001X.

In this paper, a high-frequency Chua's chaotic oscillator based on unity gain cells (UGCs) is introduced. Leveraging the internal buffers of the integrated circuit AD844, a voltage mirror (VM) and a positive current follower (CF+) are designed, taking into account the parasitic elements associated to each UGC. Afterwards, the behavior of the nonlinear resistor and of the grounded inductor are designed by using several VMs, CF+s, discrete capacitors and resistors. In this way, Chua's circuit is built by coupling a nonlinear resistor and an active LC tank circuit by using an RC passive filter. Hspice simulations performed at the state space and in the time and frequency domains show that the proposed topology generates chaos at 1.7 MHz. Experimental results are given, verifying that the chaotic spectrum is extended to high-frequency and showing close agreement with theoretical analysis. The proposed topology is compared with other topologies reported in the literature, showing that a number reduced of active devices and passive elements along with smaller supply voltages can be used to generate chaotic oscillations at high-frequency. Sensitivity and Monte Carlo analysis are also done in order to research the robustness of the proposed chaotic circuit.

Palavras-chave : Chaos; unity-gain cells; chua's circuit; double-scroll; voltage-mirror; current-mirror.

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