Simple RC chaotic oscillator

An RC oscillator exhibiting chaotic behaviour is described. It contains two opamps, a Wien bridge and a diode used as a nonlinear device. The typical waveforms, the phase portraits, the power spectra and the correlation dimension of the attractor are presented to illustrate the chaotic oscillations     

Simple log-domain chaotic oscillator

A log-domain chaotic oscillator generated from a simple model with double-scroll-like dynamics is presented. The circuit operates in current-mode and is well suited to integrated circuit implementation. Experimental verification of the proposed circuit is provided     

Implementation of a memristor-based 4D chaotic oscillator and its nonlinear control

Analog Integrated Circuits and Signal Processing - In this study, an electronic model of a memristive-based 4D autonomous chaotic system with a line equilibrium is proposed. A memristor offers many...     

Two-stage chaotic Colpitts oscillator

A novel version of the chaotic Colpitts oscillator is proposed. It contains two bipolar junction transistors coupled in series. The resonance loop consists of an inductor and three capacitors. The two-stage oscillator, compared with the classical circuit, enables the fundamental frequency of chaotic oscillations to be increased by a factor of three. The PSpice simulations performed with 9 GHz threshold frequency transistors demonstrate that the highest fundamental frequencies of chaotic behaviour are 1 and 3 GHz for the classical and the two-stage Colpitts oscillator, respectively     

混沌振荡器的计算机仿真

提出了用频变负电阻(FDNR)实现混沌振荡器的新电路,该电路结构简单,易于集成,仅用一个接地的频变负电阻作为有源器件,用二极管提供必要的非线性。并给出了电路的数学模拟和PSpice仿真。模拟和仿真结果表明,二者取得了很好的一致。     

微波混沌信号发生器技术研究进展

混沌(Chaos)是非线性动力学系统特有的一种运动形式,是确定性系统中出现的极其复杂的、类似随机的现象.合理利用混沌的多种特性可以有效地改善通信系统性能.基于其原理的混沌载波扩频通信是一种鲁棒性强、保密性好、实现简单的潜在应用价值的方案,可对当前的CDMA扩频体制做出重要的性能改善.     

High frequency Wien-type chaotic oscillator

A Wien-type oscillator based on a current feedback opamp (CFOA) employed as a non-inverting voltage-controlled voltage source is modified for chaos by adding an inductor and a general purpose signal diode. By using a CFOA as the active element, high operating frequencies are possible. The chaotic oscillator is described by a fourth order system of differential equations. Experimental results, PSpice simulations and numerical simulation of the proposed model are included     

Generation of multi-scroll delayed chaotic oscillator

A novel delayed chaotic oscillator capable of generating multi-scroll chaos is investigated. The nonlinear activation function can be represented as a piecewise linear function, and its circuitry implementation requires only a few operational amplifiers. The typical waveforms and phase portraits of the attractor are presented to illustrate mono-, two- or four-scroll chaotic oscillations     

RC op-amp implementation of hysteresis chaotic oscillator

An RC op-amp implementation of an oscillator based on hysteretic nonlinearity is proposed. Experimental results are reported, showing its main dynamic behaviours     

Improved chaotic Colpitts oscillator for ultrahigh frequencies

A novel version of the Colpitts oscillator is presented generating chaotic oscillations at gigahertz frequencies. In contrast to the standard oscillator the inductor is moved from the collector circuit of the transistor to the base circuit. PSpice simulations demonstrate chaos at the fundamental frequencies of 0.5, 1 and 2 GHz employing transistors with a threshold frequency of 9 GHz.     

一种新的混沌振荡器设计方法

介绍了一种具有普适性的混沌振荡器设计方法,该方法完全基于无量纲状态方程设计,整个电路由反相加法模块、积分模块和反相器模块三大模块组成.各状态变量以原变量和反变量的形式出现,设计者只需根据系统状态方程,将各模块连接起来就可实现,大大简化了混沌电路的设计,实现了混沌电路的模块化设计.根据该方法,文中分别设计了Lorenz、...     

Delayed feedback chaotic oscillator with improved spectral characteristics

A chaotic oscillator, including a nonlinear unit, an amplifier, an RC filter and a delay line, is described. Depending on the gain the circuit exhibits mono- or two-scroll chaotic oscillations. The two-scroll oscillations, in comparison with the mono-scroll oscillations, are characterised by three times higher fundamental frequency.     

Modeling and simulation of a chaotic oscillator by MATLAB

A MATLAB-based system is presented to model and simulate a chaotic oscillator. Chua’s circuit is selected to describe the chaos phenomenon. Furthermore, the nonlinear resistor (Chua’s diode) is modeled by an I-V piecewise-linear characteristic whose current and voltage ranges can be varied by the user. It is shown how to generate a sequence of chaotic behaviors by varying the value of a linear resistor. The simulation results can be plotted in a 2D and 3D graphs. Finally, it is described the synthesis of the chaotic oscillator by using standard CMOS integrated-circuit technology.     

On the realization of circuit-independent nonautonomous pulse-excited chaotic oscillator circuits

The aim of this paper is to present a simple circuit design method for realizing a nonautonomous chaotic oscillator given a second-order sinusoidal oscillator with two capacitors. The proposed method relies on applying a periodic pulse train, as an exciting source, and the addition of a signum-type nonlinear transconductor to the given sinusoidal oscillator. Experimental results of designed circuits are shown.     

A low-power biologically-inspired chaotic oscillator with process and temperature tolerance

This paper presents a low-power, biologically-inspired silicon neuron based implementation of a chaotic oscillator circuit. The silicon neuron structure is based on Hodgkin–Huxley neuron model. Subthreshold MOSFET and current reuse techniques have been utilized to achieve a low-power consumption of 180.30 nW for the room temperature (27 °C) and typical process corner. The chaotic behavior of the circuit is confirmed by calculating the largest Lyapunov exponent. A sensitivity analysis of the proposed chaotic oscillator shows that the circuit maintains the chaotic behavior for five different process corners within the temperature range of 0–60 °C.     

Double scroll in a simple `2D' chaotic oscillator

A very simple RC oscillator exhibiting the double-scroll chaotic attractor is described. The circuit contains two opamps, a Wien bridge, and two diodes used as nonlinear devices. The typical waveforms and the phase portraits of the attractor are presented to illustrate the double scroll in a quasi-two-dimensional oscillator     

Simple single longitudinal mode Q-switched Nd:YAG oscillator

A simple three-mirror resonator is considered for longitudinal mode control in a passivelyQ-switched Nd:YAG laser. This configuration provides temporally smooth output pulses with duration determined by dye concentration and continuously variable from 300 to 10 ns. Previous problems with spatial beam quality can be minimized by careful arrangement of cavity components.     

Implementation of a chaotic oscillator by designing Chua’s diode with CMOS CFOAs

The implementation of a chaotic oscillator which is based on Chua’s circuit, is presented. Chua’s diode is realized by using current feedback operational amplifiers (CFOAs). Furthermore, it is shown that a CMOS compatible CFOA can be designed by connecting two voltage followers sandwiched between two current mirrors. The proposed implementation is biased at ±1.2 V, and simulated by using SPICE and standard CMOS technology of 0.35 μm. Finally, simulation results are presented to show the sequence of chaotic behaviours for increasing values of the linear resistance. Esteban Tlelo-Cuautle received the B.Sc. degree in electronics engineering from the Technologic Institute of Puebla (ITP) México, in 1993, the M.Sc. and Ph.D. degrees from the National Institute for Astrophysics, Optics and Electronics (INAOE) México, in 1995 and 2000, respectively. In 1995 he joined the Department of Electronics at the ITP. Since 2001 he has been with the Department of Electronics at INAOE, where he is currently a Researcher. He has been member of reviewer-committees for the IEEE Trans. on CAS-I, IEEE Trans. on Education, IEEE Latin-America, Información Tecnológica, SCI Journal, IASTED, and IEEE ISCAS. He is member of IEICE, Senior Member of the IEEE, and his research interest include electronic design automation, modeling and simulation, symbolic analysis, circuit synthesis, and analog and mixed-signal CAD tools. Aarón Gaona-Hernández was born in Puebla, México in 1980. He received his B.Sc. degree from the Faculty of Sciences for Electronics at the Autonomous University of Puebla (BUAP-FCE), in 2005. His research interest include analog IC design and chaotic systems. Joel García-Delgado is with the BUAP-FCE México.     

Formation and suppression of stationary and chaotic oscillations in a non-autonomous gyrotron backward-wave oscillator

Formation and suppression of chaotic oscillation modes in a non-autonomous gyrotron backward-wave oscillator is studied. It is shown that, in the considered system, developed chaotic oscillations and stationary single-frequency oscillations can be formed in a gyrotron tube upon variation in the frequency and power of an external signal. Domains in the plane of basic control parameters are found in which the considered oscillation modes of a non-autonomous gyrotron backward-wave oscillator are observed.     

CMOS 2.4 μm chaotic oscillator: experimental verification ofchaotic encryption of audio

The authors report the first experimental verification of chaotic encryption of audio using custom monolithic chaotic oscillators. We use G_m-C techniques to realise a chaotic modulator/demodulator IC that implements a 3rd-order nonlinear differential equation. This has been fabricated in 2.4 μm double-poly technology and includes on-chip tuning circuitry based on amplitude detection. Measurements demonstrate how to exploit the synchronisation between two of these ICs for encrypted transmission