Non-autonomous Chaotic Circuit Research Articles

Emergence of chaotic hysteresis in a second-order non-autonomous chaotic circuit

The observation of hysteresis in the switching between the attractors of a third-order autonomous chaotic system namely, the Chua’s circuit has been reported recently (Gomes et al., 2023). In the present work, we make a detailed study on the emergence of chaotic hysteresis in the switching between the attractors of MLC circuit. The experimental realization of chaotic hysteresis is further validated by numerical simulation and analytical solutions. The presence of chaotic hysteresis in a second-order non-autonomous electronic circuit is reported for the first time. Multistable regions are observed in the dynamics of MLC with constant bias.

A novel fractional nonautonomous chaotic circuit model and its application to image encryption

Abstract A novel fractional nonautonomous system is proposed by introducing fractional order meminductor-memristor based circuit. Four circuit models are presented by different arrangements for the elements and the dynamic behaviors for each circuit are explored. It is observed that the four systems exhibit chaotic and hyperchaotic behaviors which have been verified using Lyapunov exponents. Bifurcation diagrams and phase portraits are employed to examine the effects of parameters variation on the qualitative dynamics of each model. An image encryption scheme is presented based on pseudo chaos orbit generated by two interval extensions of chaotic circuit model. The security analysis is carried out to verify the robustness and efficiency of the encryption scheme against possible attacks.

Design, modeling and research of the new non-autonomous chaotic generator

Introduction. General scientific fields where can be used non-autonomous circuits that realize chaotic behavior and generate chaotic oscillations are presented. Main characteristic about non-autonomous chaotic circuits is described. For modelling, analysis and demonstrate results was selected MultiSim software environment. Modelling of Non-Linear Element. The simplest chaotic non-autonomous second-order circuit which belongs to the single-loop RL-diode series circuit, system of equations has described RLC circuit and theoretical nonlinear characteristic and circuit for realization of nonlinear characteristic, nominal components, parameters are presented. This non-linear element has designed to have a piecewise-linear characteristic and built only in one opamp. For realization of nonlinearity use only one bipolar power source for the opamp is enough. Results of computer modelling and simulation using MultiSim, i.e. the volt-ampere characteristic (VAC) at certain values of the components of the scheme's nominal values, is presented. Modelling and Analysis of the New Non-Autonomous Chaotic Circuit. System’s behaviour is investigated through numerical simulations, by using well-known tools of nonlinear theory, such as chaotic attractor and time distributions of the chaotic coordinates. This designed non-autonomous circuit, which generate a chaotic attractor, can be used in modern transmission and reception systems of information. Conclusions. For the first time was designed a new non-autonomous circuit that generate chaotic oscillations. The circuit, system of equations that describe circuit and nominal of components are presented. This circuit that generate chaotic oscillations can be used as one of the main part of modern telecommunication systems for masking and decrypt of information carrier.

Realization of Chaotic Circuits Using Lambda Diode

This paper presents the design of novel autonomous and non-autonomous inductorless chaotic circuit using lambda diode. The autonomous chaotic circuit is implemented using Chua’s circuit, where the piece-wise linear element of Chua’s circuit called Chua’s diode is replaced by lambda diode. The lambda diode used as a nonlinear resistor in Chua’s circuit comprises of BJT, FET and resistors. The non-autonomous chaotic circuit is studied by replacing the piece-wise linear element of Murali–Lakshmana–Chua (MLC) circuit by lambda diode. The reason for employing lambda diode is that it has a wide range of negative resistance characteristics, which enable the circuit to operate at higher frequency ranges. The resulting chaotic oscillator can easily be made to operate at both low and high frequencies. The chaotic behavior of the circuit is established through Multisim simulations in the time and frequency domains. Both theoretical analysis and electronic circuit experiments are presented. The circuit’s chaotic characteristics are further confirmed by means of Poincare plot and the Bifurcation diagram. The observed route to chaos is period-adding.

Bistable Nonvolatile Elastic-Membrane Memcapacitor Exhibiting a Chaotic Behavior

We suggest a realization of a bistable nonvolatile memory capacitor (memcapacitor). Its design utilizes a strained elastic membrane as a plate of a parallel-plate capacitor. The applied stress generates low and high capacitance configurations of the system. We demonstrate that a voltage pulse of an appropriate amplitude can be used to reliably switch the memcapacitor into the desired capacitance state. Moreover, the charge-voltage and capacitance-voltage curves of such a system demonstrate hysteresis and transition into a chaotic regime in a certain range of alternating-current voltage amplitudes and frequencies. The membrane memcapacitor connected to a voltage source comprises a single-element nonautonomous chaotic circuit.

A Truly Random Number Generator Based on a Pulse-Excited Cross-Coupled Chaotic Oscillator

A non-autonomous cross-coupled chaotic circuit is presented with its derivation mechanism. To guarantee robust chaotic behavior of the circuit against parameter variations, an ideal set of parameters is determined by constructing bifurcation diagrams. A truly random number generator (TRNG), which relies on generating non-invertible binary sequences according to regional distributions of underlying chaotic signal, is also introduced. Simulation and experimental results verifying the feasibility of the circuit are given. The proposed TRNG offers much higher and constant throughput rates, allows for offset compensation and fulfills the NIST-800-22 statistical test suite without further post-processing.

MLC CIRCUIT IN THE FRAME OF CNN

A CNN-based nonautonomous chaotic oscillator circuit design is presented. Murali–Lakshmanan–Chua circuit, known as MLC circuit, is modeled by using CNN cells. The circuit implementation is supported by an eigenvalue study of the introduced system. The proposed model gives an alternative to MLC circuit with inductorless RC-based circuit realization.

Experimental synchronization of single-transistor-based chaotic circuits

This work deals with nonautonomous chaotic circuits and, in particular, with the experimental characterization of the synchronization properties of two simple nonautonomous circuits. Two single-transistor chaotic circuits, which are among the simplest chaotic oscillators, are investigated. We studied synchronization of these circuits and found that the most appropriate technique to synchronize two single-transistor chaotic circuits is that based on the design of an inverse circuit.

Internal crisis in a second-order non-linear non-autonomous electronic oscillator

The internal crisis of a second-order non-linear non-autonomous chaotic electronic circuit is studied. The phase portraits consist of two interacting sub-attractors, a chaotic and a periodic one. Maximal Lyapunov exponents were calculated, for both the periodic and the chaotic waveforms, in order to confirm their nature. Transitions between the chaotic and the periodic sub-attractors become more frequent by increasing the circuit driving frequency. The frequency distribution of the corresponding laminar lengths and their average values indicate that an internal crisis takes place in this circuit, manifested in the intermittent behaviour of the corresponding orbits.

Truly random number generators based on a non-autonomous chaotic oscillator

A non-autonomous chaotic circuit which is suitable for high-frequency integrated circuit (IC) realization is presented. Simulation and experimental results verifying the feasibility of the circuit are given. We have numerically verified that the bit streams obtained from the stroboscopic Poincaré map of the system passed the four basic tests of FIPS-140-2 test suite. We also have verified that the binary data obtained from the hardware realization of this continuous-time chaotic oscillator in the same way pass the full NIST random number test suite. Then, in order to increase the output throughput and the statistical quality of the generated bit sequences, we propose a TRNG design which uses a dual oscillator architecture with the proposed continuous-time chaotic oscillator. Finally, we have experimentally verified that the binary data obtained by this oscillator sampling technique pass the tests of full NIST random number test suite without Von Neumann processing for a higher throughput speed while compared with the previous one where the proposed continuous-time chaotic oscillator is used alone.

Nonlinearities from a non-autonomous chaotic circuit with a non-autonomous model of Chua's diode

A numerical study is carried out on the dynamics of a non-autonomous chaotic circuit. The parametrical dependencies and features of a time-dependent circuit are explored. A novel feature of the present circuit model is that it contains a new non-autonomous nonlinear sub-circuit, namely, a non-autonomous Chua's diode (NCD), which indicates nonlinear resistor behaviour and enhances the complexity of the standard Chua's diode. Periodic cases are observed as functions of voltage f, driving frequency ω and the frequency of NCD ϕ. Chaos occurs for appropriate system parameters.

The smallest transistor-based nonautonomous chaotic circuit

A nonautonomous chaotic circuit based on one transistor, two capacitors, and two resistors is described. The mechanism behind the chaotic performance is based on "disturbance of integration". The forward part and the reverse part of the bipolar transistor are "fighting" about the charging of a capacitor. Measurements and PSpice experiments are presented.

A Simple Nonautonomous Chaotic Spiking Circuit with a Refractory Threshold

This letter studies a simple nonautonomous chaotic circuit constructed by adding an impulsive switch to the RCL circuit. The switch operation depends on time and on state variable through a refractory threshold. The circuit exhibits various chaotic attractors, periodic attractors and related bifurcation phenomena. The dynamics can be analyzed using 1-D return map focusing on the time-dependent switching moments. Using a simple test circuit model typical phenomena are verified in PSPICE simulations.

INDUCTORLESS REALIZATION OF NONAUTONOMOUS MLC CHAOTIC CIRCUIT USING CURRENT-FEEDBACK OPERATIONAL AMPLIFIERS

An inductorless realization of nonautonomous (Murali–Lakshmanan–Chua) MLC chaotic circuit is proposed. The main purpose of this study is to improve the performance of nonautonomous MLC chaotic circuit using only CFOAs. CFOA-based topology used in this realization enables to simulate floating inductance. This modification provides to the designer wideband chaotic signals for secure communication systems. In addition to this major improvement, a CFOA-based nonlinear resistor was used in the new realization of nonautonomous MLC chaotic circuit. The usage of CFOA-based inductance simulator and nonlinear resistor in the circuit structure reduces the component count and provides isolated outputs. The performance of the proposed inductorless nonautonomous chaotic circuit is demonstrated with both PSpice simulations and experimental results.

MIXED-MODE CHAOTIC CIRCUIT AND ITS APPLICATION TO CHAOTIC COMMUNICATION FOR TRANSMISSION OF ANALOG SIGNALS

We present a mixed-mode chaotic circuit which has both autonomous and nonautonomous chaotic circuit dynamics and we show how this mixed-mode chaotic circuit can be utilized in a chaotic communication system for transmitting analog signals. The investigation of static and dynamic analyses of the proposed circuit has been carried out and its chaotic behavior was verified by PSpice simulation experiments. For the transmission of analog signals via mixed-mode chaotic circuit, a well-known chaotic communication system introduced by Itoh et al. was chosen.

Non-autonomous second-order chaotic circuit with comparator

A novel non-autonomous nonlinear oscillator is suggested. The oscillator contains the integrator based second-order RC resonance loop, a comparator employed as a nonlinear device, and a buffer. When externally forced with periodic signal Asin(/spl omega//sub d/f), it exhibits a chaotic response in the certain bands of A and /spl omega//sub d/ parameters.

Mixed-mode chaotic circuit

A switching method is used to design a novel and extremely simple form of mixed-mode chaotic circuit which has both autonomous and nonautonomous chaotic circuit dynamics. The static and dynamic performances of the proposed circuit have been investigated and its mixed-mode chaotic behaviour verified by computer simulations.

SYNCHRONIZING NONAUTONOMOUS CHAOTIC SYSTEMS WITHOUT PHASE-LOCKING

Pecora and Carroll1 have shown how two nonautonomous chaotic circuits driven by periodic forcing can be synchronized using the master-slave driving principle. However, in their scheme, the periodic forcing in both circuits needs to be phase-locked through some additional circuitry for the system to synchronize. In this paper, we show two ways in which this can be avoided. In the first scheme, the two circuits are connected in a master-slave driving configuration and the periodic forcing is included in the driving signal such that it eliminates the need for the slave circuit to have an external periodic forcing signal. In addition, we can recover the periodic forcing signal at the slave circuit. In the second scheme, the two circuits are connected in a mutual coupling configuration. The two circuits will synchronize regardless of what the periodic forcing signals of the two circuits are. In particular, the two periodic forcing signals could have different phases, different frequencies, or different shapes. We discuss two interpretations of these synchronization schemes. First, we consider them as communication systems when the periodic forcing signal is replaced by a properly encoded information signal. We illustrate this in a physical circuit implementation. Second, we consider them as synchronization schemes for nonidentical systems by considering the external forcing signal as an error signal due to the difference between the two systems.

The simplest dissipative nonautonomous chaotic circuit

We show by computer simulation that chaos can occur in a sinusoidally driven second-order circuit made of three linear elements and a Chua's diode. Unlike many other nonautonomous second-order chaotic circuits whose nonlinear element is a nonlinear capacitor, the Chua's diode is a nonlinear resistor, and is therefore simpler from a circuit-theoretic point of view.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>