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     

Simple 4D chaotic oscillator

An extremely simple 4D chaotic oscillator is presented. It contains a single op amp, two LC circuits and a diode used as a nonlinear device. The chaotic oscillations have been characterised using the correlation dimension of the strange attractor, the Lyapunov exponents and the Lyapunov dimension. The dimensions are found to be >3     

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     

Insensitive very-low-frequency RC oscillator

The frequency-sensitivity problem associated with some types of very-low-frequency oscillators is examined and an insensitive structure is presented.     

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     

A temperature-stable RC transistor oscillator

Generation of stable sinusoidal oscillations of fairly good waveform has been realized in a basic multivibrator circuit by optimizing load and coupling elements and introducing an amplitude defining mechanism with the use of emitter coupling. The resulting differential operation introduces an inherent tendency of self-compensation against changes of active circuit parameters, and the frequency remains practically independent of temperature change even though transistors are used.     

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     

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.     

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。     

Chaos in a novel Wien bridge-based RC chaotic oscillator: dynamic analysis with application to image encryption

Analog Integrated Circuits and Signal Processing -     

New type of variable-frequency RC oscillator

A technique of realising a variable-frequency RC oscillator is proposed. The frequency of oscillation is found to be the difference of two RC functions, which permits a very-low-frequency realisation. The frequency variation is obtained by controlling a single resistance in the network.     

一种新型高精度RC振荡器电路设计

在对传统的振荡器电路的分析比较基础上,基于振荡器的基本工作原理,结合误差比较器技术,提出了一种新型高性能低功耗的RC振荡器.利用CSMC的DPDM Bsim3模型和Cadence的Spectre仿真器对该电路进行了模拟和仿真,结果表明该电路与传统的振荡器相比具有精度高、功耗低的优点.最后对该电路进行版图设计,版图面积为70.5×62.59μm2.     

Nullor representation of variable-frequency RC oscillator

A recently proposed RC oscillator is represented in nullor form. By rearranging the nullors, it is shown that only one operational amplifier is required, instead of two. Means are proposed to overcome a bias problem inherent in the original design.     

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     

Fast amplitude stabilization of an RC oscillator

A technique is proposed for stabilizing the output amplitude of a variable-frequency RC sine-wave oscillator. Amplitude settling time is reduced by converting amplitude to a d.c. voltage having only a small ripple content, which requires little filtering. A relationship between amplitude transient response and harmonic distortion is demonstrated, and the results are compared to those obtained by more conventional methods.     

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、...     

RC正弦波振荡电路教学设计

本文以8音阶简易电子琴电路引入,从信号产生和8音阶实现两个问题入手,引出RC正弦波振荡电路理论,并拓展应用到实现简易电子琴的设计.通过全员参与,步步设疑,层层探究,理论与应用结合,激发了学员兴趣,提高了学员能力.     

Nonautonomous pulse-driven chaotic oscillator based on Chua's circuit

A novel nonautonomous chaotic oscillator based on the passive structure of Chua's circuit is proposed. Unlike most of the available members of this class of chaotic oscillators, the proposed circuit is driven by a periodic bipolar pulse-train rather than by sinusoidal excitation. This results in equilibrium points which have fixed positions in space. The circuit employs self feedback via a single comparator, which is the only nonlinear device involved. The output of this comparator is a chaotic bipolar pulse-train. A mathematical model which captures the behavior of the circuit is derived and experimental results are presented. Also, a version of the circuit with a practical realization of the driving pulse generator is considered and a variant structure with an alternatively excited node is discussed.     

基于CCII的集成混沌振荡器设计

集成化混沌振荡器是混沌在实际应用中的一种重要趋势,特别是在大规模的混沌系统的电子实现方面。为了使混沌振荡器的集成度更高,并且具有较宽的频带,本文提出了一种新型的电流模式混沌振荡器。通过对自治混沌振荡器的电路模型分析,在文氏混沌电路基础上,采用CCII电路代替电压运算放大器、跨导运算放大器等传统运算放大器,实现了正弦波振荡电路,通过采用NMOS管将两个正弦振荡电路耦合最终实现电流模式混沌振荡器,通过对该电流模式混沌振荡器建模并进行仿真分析,描述了该振荡器的混沌行为,验证了该混沌电路的有效性和可行性。再通过仿真结果对比表明该混沌振荡器相比于传统的文氏混沌振荡器功耗更小、噪声抑制能力更强,由其产生的混沌信号在频带宽度、随机程度方面都有明显提高,更适合芯片集成。