Active RC realization of RL impedances

In this communication, an active RC circuit realizing RL impedance is proposed. It uses an amplifier and three passive elements; and realizes both linear and bilinear RL impedances.     

RC电路的应用

RC电路在模拟电路、脉冲数字电路中得到广泛的应用，由于电路的形式以及信号源和R，C元件参数的不同，因而组成了RC电路的各种应用形式：微分电路、积分电路、耦合电路、滤波电路及脉冲分压器。     

Active RC realization of a bilinear RL impedance

A circuit configuration utilizing a differential-input dual-output operational amplifier to simulate a bilinear RL impedance approximating an inductor is presented. The advantages of the method are that the value of the parameters can be varied by adjusting a potentiometer and the capacitor used has one of its terminals connected to ground.     

Comments on "Active RC realization of RL impedance"

It is pointed out that the configurations presented in the above letter have been previously known in the literature.     

RC Distributed Circuits for Vibration Damping in Piezo-Electromechanical Beams

An RC distributed circuit is proposed in the paper to control vibrations in piezo-electromechanical systems. The circuit is designed on the basis of a distributed electromechanical model obtained, in particular, for Euler beams. The aim is to achieve mechanical damping while relaxing the constraints on the electrical design. With respect to previous RL approaches, the proposed RC circuit performs better and avoids the use of floating inductors, whose implementation is complex and critical in the stabilization sense. Conversely, even if negative capacitors are necessary, their active realization is simpler and the whole stability of the system can be directly controlled based on explicit constraints derived in the paper.     

一阶RC电路时域分析和频域分析的对比

本文以一阶RC积分电路和微分电路为例,分别给出了这两个电路的时域和频域分析结果.对这些分析结果进行对比,并从信号处理的角度做出定性解释,表明对同一电路从时域和频域两个不同角度得到的结论在本质上是一致的.对动态电路的这种对比分析,有利于加深学生对动态电路本质的理解,并且对不同章节的内容建立统一的认识.     

RLC synthesis of certain functions with real poles and zeros not expressible as the product of an RC and an RL function

Using the new-found result that RC × RL-functions are synthesisable employing 1st-order building blocks only, a subclass of higher-order non-RC × RL functions is indicated, which needs only canonically realisable 1st-order and 2nd-order subnetworks for its straightforward RLC realisation.     

Optimization of Fractional-Order RLC Filters

This paper introduces some generalized fundamentals for fractional-order RL _β C _α circuits as well as a gradient-based optimization technique in the frequency domain. One of the main advantages of the fractional-order design is that it increases the flexibility and degrees of freedom by means of the fractional parameters, which provide new fundamentals and can be used for better interpretation or best fit matching with experimental results. An analysis of the real and imaginary components, the magnitude and phase responses, and the sensitivity must be performed to obtain an optimal design. Also new fundamentals, which do not exist in conventional RLC circuits, are introduced. Using the gradient-based optimization technique with the extra degrees of freedom, several inverse problems in filter design are introduced. The concepts introduced in this paper have been verified by analytical, numerical, and PSpice simulations with different examples, showing a perfect matching.     

Approximated Fractional-Order Inverse Chebyshev Lowpass Filters

In this paper we use a least-squares fitting routine to approximate the stopband ripple characteristics of fractional-order inverse Chebyshev lowpass filters which have fractional-order zeros and poles. MATLAB simulations of \((1+\alpha )\)-order lowpass filters with fractional steps from \(\alpha =0.1\) to \(\alpha =0.9\) are given as examples. SPICE simulations of 1.2-, 1.5-, and 1.8-order lowpass filters and experimental results of a 1.5-order filter using approximated fractional-order capacitors in a Multiple-Input Biquad circuit validate the implementation of these circuits.     

带有干扰观测器的分数阶滑模控制

针对一类带有匹配不确定性的系统,结合分数阶理论设计分数阶滑模控制器,在保证控制精度的同时,更好地削弱系统中存在的抖振;针对系统中存在的不确定量,利用干扰观测器来估计;最后对系统稳定性进行分析。通过仿真验证可以看出,所用方法不仅能很好地估计不确定量,而且能极大降低系统抖振。     

State-Space Self-Tuning Control for Stochastic Fractional-Order Chaotic Systems

Based on the modified state-space self-tuning control (STC), a novel low-order tuner via the modified observer/Kalman filter identification (OKID) is proposed for stochastic fractional-order chaotic systems. The OKID method is a time-domain technique that identifies a discrete input-output map by using known input-output sampled data in the general coordinate form, through an extension of the eigensystem realization algorithm (ERA). First, the estimated system in the general coordinate based on the conventional OKID method is transformed to the one in an observer form to fit the state-space innovation form for the STC. Then, in stead of the conventional recursive least squares (RLS) identification algorithm used for STC, the Kalman filter as a parameter estimator with the state-space innovation form is presented for effectively estimating the time-varying parameters. Besides, taking the advantage of the digital redesign approach, the derivation of the current-output-based observer is proposed for the modified STC. As a result, the low-order state-space self-tuner with the high-gain controller property is then proposed for stochastic fractional-order chaotic systems, which the fractional operators are well approximated using the standard high integer-order operators. Finally, the fractional-order Chen and Roumlssler systems with stochastic system process and measurement noises are used as illustrative examples to demonstrate the effectiveness of the proposed methodology     

从RC5到RC6

论文详细描述并分析了从RC5到RC6的演化设计过程,在详细研究了RC6性能的同时,指出了应该如何从一个旧的密码设计出好的新密码。最后对RC6和Rijndael作了一些比较,指出各自在性能上的优缺点。     

Highly-Accurate Fractional-Order Microwave Differentiators for Band-Specific UWB Applications

Wireless Personal Communications - Highly accurate designs of band-specific fractional-order microwave differentiators are proposed to operate in lower and upper frequency bands of UWB range....     

有源电路和无源电路术语的讨论

本文讨论了理想电路、实际电路中有源电路和无源电路术语的精确含义和受控源的概念,指出理想电路中有源电路和无源电路术语容易引起歧义;举例说明含有有源元件的理想电路既可以是有源电路,也可以是无源电路。笔者提出了对理想电路应使用理想有源电路和理想无源电路术语,对实际电路应使用实际有源电路和实际无源电路术语的观点。     

Numerical Solution for Fractional-Order Differential Systems with Time-Domain and Frequency-Domain Methods

For a general nonlinear fractional-order differential equation, the numerical solution is a good way to approximate the trajectory of such systems. In this paper, a novel algorithm for numerical solution of fractional-order differential equations based on the definition of Grunwald-Letnikov is presented. The results of numerical solution by using the novel method and the frequency-domain method are compared, and the limitations of frequency-domain method are discussed.     

Ferrite Planar Circuits in Microwave Integrated Circuits

The ferrite planar circuit to be discussed in this paper is a general planar circuit using ferrite substrates magnetized perpendicular to the ground conductors. The main subject of this paper is the analysis of an arbitrarily shaped triplate ferrite planar circuit. In particular, the circuit parameters of the equivalent multiport are determined. To analyze ferrite planar circuits in general, two approaches are possible. One approach is based upon a contour-integral solution of the wave equation. In the other approach the fields in the circuit are expanded in terms of orthonormal eigenfunctions. Examples of the application of such analyses are described.     

A New Fractional-Order Chaotic System and Its Synchronization with Circuit Simulation

A new fractional-order chaotic system is proposed in this paper, and a list of state trajectories is presented with fractional derivative of different areas. Furthermore, a circuit diagram is studied to realize the fractional-order chaotic system. The new fractional-order chaotic system can be controlled to reach synchronization based on the nonlinear control theory, and the results between numerical emulation and circuit simulation are in agreement with each other.     

Design of Wideband Fractional-Order Differentiator Using Interlaced Sampling Method

In this paper, the design of a wideband digital fractional-order differentiator (FOD) is investigated. First, conventional FOD designs are reviewed, and the reconstruction formula of the interlaced sampling method is used to design the proposed wideband FOD by index substitution and the Grünwald–Letnikov fractional derivative. Because a closed-form window design is obtained, the filter coefficients are easily computed. Then, the weighted least squares and convex optimization methods are applied to design non-sparse digital FODs that are optimal in the least squares or min–max sense. Next, the iterative hard thresholding and orthogonal matching pursuit methods are used to design sparse digital FODs to reduce the implementation complexity. Finally, several numerical examples are presented to show that the proposed FODs have smaller design errors in the high-frequency band than conventional digital FODs that do not use the auxiliary interlaced sampling signal.