分数阶记忆元件转换关系的研究

记忆元件作为新型电路元件,其特殊的记忆特性引起了科研人员的广泛关注.从记忆元件的本构方程出发,推导出了记忆元件之间的转换关系,仿真实现了三种分数阶记忆元件之间的相互转换.仿真实验结果验证了分数阶记忆元件之间相互转换关系式的正确性.同时,也详细分析了分数阶阶次对记忆元件影响的规律.     

电路元件周期表——蔡氏周期表与新型记忆元件

在介绍蔡氏周期表的基础上,给出已有电路元件(电阻、电容、电感、忆阻、忆容、忆感、分抗和分忆抗元等)在周期表中的位置。近年来,“分数阶忆阻”的概念开始逐渐出现在文献中,但其概念并不统一。本文将已有的分数阶忆阻及电路总结为4种,并确定对应的元件在蔡氏周期表中的位置。分数阶积分是表征有损记忆的有力工具,本文不仅给出电路元件禀赋关系统一表示式,还给出分数阶积分控制式记忆元件——电流分数阶积分控制式忆容(CFMC)、电压分数阶积分控制式忆容(VFMC)、电流分数阶积分控制式忆感(CFMI)、电压分数阶积分控制式忆感(VFMI)、电流分数阶积分控制式分忆抗(CFFM)、电压分数阶积分控制式分忆抗(VFFM)等的定义,并给出部分分数阶积分控制式记忆元件的运算结构图。     

电容的分数阶等效电路建模与分析

实际的电容器件都是非理想的,其特性受到各种因素的影响,建立精确的电容模型对于电路系统分析与设计十分必要。考虑到电容的分数阶微积分特性,文中基于传统的电容整数阶等效电路模型,提出电容的分数阶等效电路模型,并采用差分进化算法辨识出模型参数,然后将该模型应用于Buck电路进行纹波电压的分析。仿真结果表明,同传统整数阶等效电路模型相比,分数阶等效电路模型拟合电容实际数据的准确度更高,验证了该电容分数阶等效电路模型的有效性。     

一种分数阶混沌系统的通用增强型FPGA实现

针对目前分数阶混沌系统的FPGA设计实现通用程度不高的问题,文中给出了一种通用增强型FPGA算法。首先给出基于G-L定义的分数阶微分算法原理,再将一个已知的三维整数阶混沌系统扩展至分数阶多涡卷混沌系统,通过平衡点、分岔图及最大李氏指数谱分析了其动力学特性,最后运用可变长度移位寄存器,设计分数阶微分的通用增强型FPGA算法,并将其应用至分数阶多涡卷混沌系统。实验结果与数值仿真结果一致,该算法当修改参数时,无需设计新的代码,并能够动态调节记忆长度,且对步长没有严格限制。     

一种新的分数阶记忆多项式预失真器

该文针对由记忆多项式设计的功率放大器预失真系统,提出了一种新的分数阶记忆多项式预失真器。提出预失真多项式是在常用记忆多项式基础上,通过去掉偶数阶项增加分数阶项以提高线性化性能。文中给出了分数阶记忆多项式的表达式,并给出了相应的系数估计算法。仿真分析表明,针对Wiener-Hammerstein和记忆多项式模型的功率放大器,在两种典型记忆多项式预失真的基础上可以分别得到10 dB和8 dB的带外谱抑制增益。相应的FPGA实现表明该预失真多项式总体硬件资源增加的代价并不高,易于在实际系统中应用。     

基本电子电路

TN701TN713.8 99020488n阶传输函数的CC实现/何怡刚(湖南大学电气系)11电子科学学刊.一1 998,20(5).一716一720文中提出了两个基于积分器的通用CC网络结构.该结构是在典型F LF结构的基础上增加输人分布和输出求和CC网络生成的.适当设置输入分布和输出求和CC网络元件参数,能实现任意高阶传输函数.文中给出了系统的设计公式。图3参7(李)便地根据实际需要编制自动测试与分析程序.(许)TN7OI 99020489电路拓展理论的公式及证明/王贵竹,熊炳kull(安徽大学)11电路与系统学报.一1 998,3(2)一50一55文中依据作者之一提出的环形等效电路,不仅…     

基于LTCC技术的椭圆函数低通滤波器设计

随着无线通信领域的快速发展,人们对微波滤波器性能的要求也越来越高。文章根据滤波器的分类和特点,研究了集总元件滤波器引入传输零点的规律和方法,分析并对比了三种不同类型低通滤波器的衰减特性。根据设计指标要求,基于LTCC技术设计了一款高性能小型化的椭圆函数七阶低通滤波器。滤波器的等效电路包括串联支路中的4个电感和并联支路中的3个LC谐振腔,共10个元件。通过对滤波器模型物理结构的优化,减小了滤波器内部元件间的寄生耦合效应,并在阻带中成功引入了传输零点,改善了滤波器的性能。     

掩埋隧道结VCSEL芯片小信号等效电路模型

提出了适用于一种1.55μm掩埋隧道结垂直腔面发射激光器(VCSEL)芯片的小信号等效电路模型.等效电路的提出是基于半导体激光器速率方程以及VCSEL芯片结构,电路中各元件都有严格的物理意义.根据实验测得芯片的反射系数及传输参数,通过小信号等效电路仿真模拟,得到电路各元件参数值.不同偏置电流下,模拟结果与实验结果吻合都非常好,证明了该等效电路的有效性.     

频率选择表面等效电路的计算与分析

提出一种利用全波数值计算和等效电路理论反演介质中频率选择表面(FSS)等效电路的方法。该方法物理过程直观,适用于任意形状FSS等效电路的精确求解。采用经典方环型FSS,验证该等效电路提取方法的可行性。最后采用该方法研究圆形缝隙型FSS结构尺寸、介质材料以及电磁波入射角对其等效电路参数的影响规律,为后续FSS等效电路研究及快速设计奠定理论基础。     

应用在GSM系统MS中的新型有源滤波器

给出一种新颖可用于GSM系统手持机MS的甚小型多层平面有源滤波器的结构、等效电路模型和分析方法.计算并讨论了1.9GHz频率下该滤波器的结构参数值、等效电路元件值和结构参数.计算表明在通带范围内该滤波器具有低噪声性能.     

基于分数阶忆阻器的混沌电路分析与设计

提出了一种新型的分数阶忆阻混沌电路.首先,建立了分数阶忆阻器的数学模型,通过数值仿真验证了分数阶广义忆阻器满足忆阻器的基本特性.然后,将分数阶广义忆阻器与蔡氏振荡电路相结合,建立了一种基于分数阶广义忆阻器的混沌电路模型.通过稳定性理论,对分数阶系统的稳定性进行了分析.为了进一步研究电路参数对系统动态行为的影响,利用相位...     

Small signal equivalent circuit modeling of resonant converters

A general analytical procedure is presented for the equivalent circuit modeling of resonant converters, using the series and parallel resonant converters as examples. The switched tank elements of a resonant converter are modeled by a lumped parameter equivalent circuit. The tank element circuit model consists, in general, of discrete energy states, but may be approximated by a low-frequency continuous time model. These equivalent circuit models completely characterize the terminal behavior of the converters and are solvable for any transfer function or impedance of interest. With the approximate model it is possible to predict the lumped parameter poles and zeros, and to quickly determine the relevant DC gains of the output impedance and the control to output transfer function. Closed-form solutions are given for the equivalent circuit models of both converter examples. Experimental verification is presented for the control-to-output transfer functions of both series and parallel resonant converters, and good agreement between theoretical prediction and experimental measurement is obtained     

整数阶电路基本定理到分数阶电路推广及分析

近几十年来,对分数阶电路的研究逐渐深入,但对其中电路定理的分析较少,因此针对分数阶电路需要进一步探究其规律,将一些经典的电路定理推广到分数阶电路中,使得在以后的分析过程中能直接使用。本文在整数阶电路定理的基础上,运用基尔霍夫定律在分数阶电路中证明了叠加定理、替代定理、等效电源定理和互易定理,并进行了应用分析。     

FET宽带小信号等效电路的研究

介绍了一种确定宽带FET小信号等效电路参数的一种方法。该方法基于FET内部器件的Y参数(Z参数)进行分析,从中得到与频率无关的等效电路参数(电容、电感、电阻值),根据模型可以得到任意指定频率下的电路等效模型或某频带内的参数均值。通过仿真测试,该等效模型在高达25 GHz频带范围频率变化,器件参数保持恒定,并与实际器件工作状况非常吻合。     

Sneak Paths in X-Y Matrix Arrays

In this paper, an equivalent circuit of an image sensor matrix is derived for a general array containing r rows and c columns. The circuit is useful in determining the "sneak paths" that exist, the amount of element isolation required, and/or the maximum array size possible for a given design. The various sneak paths that exist and general methods to minimize them are discussed. The matrix element employed is a photoconductor in series with a p-n junction diode. The circuit derivation is also applicable to the analysis of many photosensor arrays, with or without charge storage, as well as matrix display and memory arrays.     

A new element-saving equivalent circuit for the analysis of generalcoupled n-wire transmission lines

A novel efficient method for modeling the general coupled n -wire transmission line is proposed. The equivalent circuit presented has the following advantages: (1) no balanced lines are needed; (2) all element values are positive; and (3) the number of elements required by the equivalent circuit is at most equal to the number of nonzero couplings plus one. A simple method for deriving the equivalent circuit is outlined. Examples are supplied to show the application of the method     

Broad-band determination of the FET small-signal equivalent circuit

A method to determine the broadband small-signal equivalent circuit of field-effect transistors (FETs) is proposed. This method is based on an analytic solution of the equations for the Y parameters of the intrinsic device and allows direct determination of the circuit elements at any specific frequency or averaged over a frequency range. The validity of the equivalent circuit can be verified by showing the frequency independence of each element. The method can be used for the whole range of measurement frequencies and can be applied to devices exhibiting severe low-frequency effects     

Energetically consistent modeling of passive memelements

Memory elements are suited for building self-organizing circuits. In contrast to memristive devices (nonlinear resistors with memory), memreactive devices (nonlinear capacitors or inductors with memory) are lossless and can be utilized in order to achieve more degrees of freedom in electrical circuits with respect to adaptively adjustable parameters.Fabrication of pure memreactive elements is hard yet and hence mathematical models are needed to make pioneering pre-investigations. Modeling of memreactive elements is closely related to the modeling of nonlinear reactive elements. Common memreactive models are based on a static definition. Thus, they are not passive in general. But losslessness of such devices is of great importance from a circuit theoretic point of view. We propose a modeling approach for lossless memreactive elements based on an energetic definition. In this context, a novel equivalent circuit of memory devices including memtransformer or memgyrator is introduced. A known meminductive model is utilized in simulations and comparisons between different definitions are shown in order to underly the necessity of an energetically consistent model.     

HSPICE macromodel of PCRAM for binary and multilevel storage

A general macromodel of the phase change random access memory (PCRAM) elements for use in HSPICE-based computer simulator is proposed in this paper by introducing physical models of PCRAM elements. It can simulate the dc and transient behavior of PCRAM element. In this paper, the model was integrated with the standard R/W circuit and successfully simulated the R-I curve and dependence between amplitude and width of programming pulses. A comparison between experimental and simulation results were also given. Furthermore, by including the partial crystallization states, the macromodel was developed for simulating the multilevel storage.     

The piezoelectric crystal unit—Definitions and methods of measurement

The properties of a piezoelectric crystal unit as a circuit element are characterized and defined, in terms of a general equivalent circuit that is valid at any frequency up to and including the lower UHF ranges but reduces to the conventional equivalent circuit if the parameters are properly redefined. The characteristic values such as resonance frequency and resistance, parallel resonance frequency and resistance, etc., for a crystal unit with or without other reactive elements in series and/or parallel are tabulated and their significance is illustrated with the aid of the crystal impedance and admittance diagrams. These diagrams are also used in deriving and describing the methods to be followed when determining the crystal equivalent circuit parameters by impedance bridge measurements. Techniques are developed for use with various types of impedance and admittance bridges and the relations required to determine the resonance resistance R1, resonance frequency fs, and quality factor Q0of the motional arm, and the reactance X^-0of the parallel capacitance from the measured quantitites are listed. The effects of transmission lines of various lengths between the plane of measurement in the bridge and the crystal unit are fully considered. The nature and magnitude of the sources of measurement errors, exclusive of errors in bridge calibration, are examined.