含源多端口网络源向量与参数矩阵间的关系

在电路课程中一端口网络的戴维南和诺顿定理为重点内容之一。从一端口扩展为多端口网络此两定理的表现,应予以关注。本文将给出含源多端口网络参数矩阵和源向量间的关系。以下为了叙述方便称含源的网络为含源网络,不含独立源的网络为非含独立源的网络,非含源网络仍可能是有源网络。非含源多端口网络可以用短路参数矩阵Y_0、开路参数矩阵Z_0或混合参数矩阵H表征。对含源多端口网络、全部端口开路情况下的各端口开路电压或全部端口短路情况下的各端口短路电流和部分端口开路,另一部分端口短路情况下的各端口电压和电流显然是不同的。为便于区分,以下对全部端口开路情况下的端口电压用V_(00?)表示,即,向量     

广义的诺顿——戴维宁定理

1 诺顿定理的推广和并接口端的应用形式 如图1,一个线性有源网络A,可用一个无源网络P和一些独立电源J_k(k=1,2,…,m)的并联网络A_eq来等效,其中P是令A内的独立源等于零;若取适当的2个端点构成一个端口,J_k是适当的m个端口短接时的短路电流取反向,则等效电路A_eq和原网络A,对端口外接的任意负载L_k,贡献相同的端口电压和端口电流。本文所指的任意负载通指L_k可以是线性非线性的,无源有源的,端口空载或短路的,类似单端口网络的证法,利用替代定理将端口电压以电压源替代,然后采用迭加原理,参看图2,写成矩阵的形式为     

预设控制量法求含受控源一端口网络的输入电阻

在电路理论中,除了独立电源外,还引进了“受控源”。受控源的源电压或源电流的值受电路中其它支路或元件上电压或电流的控制,本身不独立地起“激励”作用。在分析具有晶体管元件的电路时,受控源的概念是很有用的,并且经常遇到的是只含有一个受控源和线性电阻的电路模型。 在电路分析中,求不含独立源,仅含线性电阻和一个受控源的一端口网络的输入电阻,是一个比较常见的问题。一般可采用在欲求端口外接电压(电流)源,求端口的响应电流(电压),从而得出输入电阻。本文在这一方法的基础上,介绍一个比较简单而又实用的方法,即预设控量法。     

纠正“预设控制量法求含受控源一端口网络的输入电阻”一文的论点

“电工教学”第17卷第2期杨柏林同志所撰的“预设控制量法求含受控源一端口网络的输入电阻”一文中写道:“在电路分析中,求不含独立电源,仅含线性电阻和一个受控源的一端口网络的输入电阻,是一个比较常见的问题。一般可采用在欲求端口外接电压(电流)源,求端口响应电流(电压),从而得出输入电阻。本文在这一方法的基础上,介绍一个比较简单而实用的方法,即预设控制量法”(见P29)。     

含受控源单口网络的等效电阻的一种求解法

介绍了含受控源单口网络的等效电阻的一种求法。该方法尤其适用于受控源的控制量能方便地表示成端口电流或端口电压的等效电阻的求解。     

阵列系统中多端口网络噪声系数测试分析

多端口网络常用于阵列系统中进行波束合成,其噪声系数测试成为系统设计的关键问题。给出了多端口网络模型,基于将多端口网络转化换成双端口网络的思想,给出了3种测试方法。方法一和方法二将多端口网络n-1个输入端口接负载,只留一个端口作为输入,其区别是加电工作的有源双端口网络数量不同。方法三在多端口网络前接一n分路器。通过对网络信号功率和噪声功率进行详细的分析和推导,给出了不同情况下的噪声系数。通过试验验证了测试方法的正确性。     

互易性一端口网络等效阻抗的灵敏度分析

本文研究了互易性一端口网络等效阻抗对元件参数的灵敏度分析.利用互易二端口的T形等效电路,建立了等效阻抗对电阻、电感和电容的灵敏度公式.只需计算在单位电流源相量激励下的元件电流或电压,再计算这些相量的平方或乘积,便可得到严格的灵敏度.由此也为相量的平方,以及电压相量与电流相量之积找到了理论价值.     

双口形式的戴维宁定理在电路分析中的应用

本文通过网络撕裂法,将电路网络分解为共地连接的有源双口网络和无源双口网络的组合,构造戴维宁定理双口等效网络,分别求出有源双口网络开路电压和无源双口网络的Z参数,根据戴维宁定理的矩阵形式计算双端口电流。文章分析了戴维宁定理在独立电源与含受控源双口网络中的应用,通过算例说明该方法的正确性与适用性。本文的讨论可供讲授电路理论课程的教师参考。     

受控源装置

本文介绍一种能满足电路实验要求的受控源装置,讨论该装置的性能及元件的选择方法。一、受控源装置的要求及框图要想使受控源装置能模拟电路中任意支路的受控源元件,受控源装置应满足如下要求:1.电压控制量端口的输入阻抗应极大,电流控制量端口的输入阻抗近似为零。2.被控电压源端口的输出阻抗近似为零,被控电流源端口的输出阻抗应极大。     

关于在放大器电路中应用叠加原理的探讨

叠加原理是线性网络的一个重要原理,它普遍适用于一切本质上属于线性范围的网络。按照传统的定义,线性网络即由线性网络元件,独立电源组成的网络。叠加原理适用于传统的线性网络,是并无异议的。可是,对于其他网络又如何呢?在半导体放大器的教学与研究中至少遇到了下面两个问题:(1)认为低频电压放大器在小信号工作时就其端口的输入,输出特性而言是满足叠加原理的,而放大器中包含有非线性元件,因此,叠加原理也适用于此     

Indirect Adaptive External Neuro-Control for a Series Capacitive Reactance Compensator Based on a Voltage Source PWM Converter in Damping Power Oscillations

A series capacitive reactance compensator (SCRC), using a voltage source converter to inject a controllable voltage in quadrature with the line current of a power network, is capable of rapidly providing a specified and controllable magnitude of capacitive reactance compensation independent of the line current. Moreover, with a suitably designed external controller, the SCRC can also be used to damp low-frequency power oscillations in a power network. Conventionally, linear control techniques are used to design the SCRC external controller around a specific operating point, where the nonlinear system equations are linearized. However, at other operating points its performance degrades. Nonlinear adaptive neuro-controllers offer an attractive approach to overcome this degradation problem. In this paper, an indirect adaptive external neuro-controller (INDAEC) using two radial basis function neural networks (RBFNNs) is proposed to improve the damping performance of an SCRC connected to a power network. This nonlinear INDAEC needs no mathematical model of the SCRC or the power network. It provides the SCRC with improved damping performance over a wide range of system operating conditions. This is shown by results on a single machine infinite bus power system, as well as a multimachine power system     

分析线性反馈网络的新方法

本文应用回路阻抗矩阵的行列式和广义余因式导出一种分析线性反馈网络的新方法,深入系统地研究了网络函数,灵敏度、回归差、零回归差及其矩阵等,得到了规律性很强适合机辅分析的一系列公式。此法不局限于研究平面网络,特别适用于RLCM和流控电压源组成的受电压源激励的网络。     

Canonical modeling of power processing circuits based on the POPIconcept

The fundamental power-processing properties of switching converter circuits are modeled using generalized power-conservative (POPI) networks. Depending on the application, it may be most appropriate to model the first-order converter properties as those of an ideal transformer, gyrator, loss-free resistor, or other POPI network. These basic functions can be obtained either through selection of a topology that naturally possesses the desired characteristics or by addition of a suitable control network. Some well-known converter topologies are shown to behave naturally as gyrators, loss-free resistors, and constant power networks. The application of the gyrator to network two voltage sources and the use of the loss-free resistor as a unity power factor rectifier are described     

体声波传感器的系统级行为仿真

为证明六端口网络可用于体声波(BAW)传感器读出电路,对包含薄膜体声波谐振器(FBAR)和微带六端口网络的BAW传感器最小系统建立等效电路模型。在ADS软件中对FBAR建立Mason等效电路模型和对微带六端口网络建立等效电路模型。微带六端口网络的端口1连接射频源,端口2与FBAR相连,其他4个端口分别连接4个50Ω的电阻用于读取功率;在Matlab软件中分别使用根心解法和平均解法对FBAR的反射系数进行求解,解得两条反射系数与频率曲线,分析得到了两种反射系数近似计算方法的优劣,并分析了六端口网络工作频带的增宽方法。仿真结果表明,微带六端口网络能准确测量出FBAR的反射系数与频率曲线,证明六端口网络可用于BAW传感器读出电路。     

Wave spreading evaluation of interconnect systems

This paper derives general multiport interconnect constraints and presents a new approach, wave spreading evaluation (WSE), which uses S-parameter based network techniques to analyze coupled, multiconductor interconnect systems for high speed analog and digital integrated circuits. WSE is based on the spreading process of voltage waves with initial spreading waves created by the sources. The spreading process is independent of input sources, and every step of wave spreading meets the constrains of KCL and KVL. The continual spreading of voltage waves will create accurate results. Since the spreading voltage waves is the process of energy attenuation, the WSE method is always convergent for passive networks     

The Future – Vision and Challenges (Seen from a Cellular Operator's Perspective)

The current trend within the development of the telecommunication networks indicates that the user will constantly be connected to the network independent on the locations and the covering network. In the following, this is defined as “Always on – everywhere”. Being always on everywhere requires more heterogeneous access networks, more intelligent services and a significant increase in the available capacity in the transmission- and the core network as well as a technology convergence. In the following, we will cover some of the ongoing trends towards a common high capacity infrastructure and what it requires to get there. An overall view will be presented on how the services, their availability, the bit rates and the infrastructure may develop. Most of the examples are seen from a cellular operator's perspective due to the background of the authors. The content of the paper reflects only the view of the authors and not necessarily the one of the TeliaSonera group.     

A compact planar ultra-broadband sum-and-difference network

In this paper, the design of a planar ultra-broadband sum-and-difference network is presented. This network employs a novel power divider and anti-phase balun as a building block. An equivalent 180° coupler with a bandwidth of 6.2 - 14GHz is achieved by back-connecting the power divider and balun together. Four such couplers are connected to form an ultra-broadband sum-and-difference network which has a bandwidth of 91%. This network, with insertion loss less than 1.8dB in sum port and nulls less than -20dB in all delta ports, is verified to be excellent, resulting in the advantages of being compact, easy manufacturing and low cost.     

我国部分进口交换机接入本地网网管系统情况

本文概要介绍Ｓ１２４０等８种进口交换机接入我国本地网网管系统的情况。     

Analysis of the equal-delay topology for transformers and hybrid networks

A complete scattering matrix representation for the ideal equal-delay topology for transformers and hybrid networks is presented. It is shown that while the operation of the hybrid as a 180/spl deg/ power combiner, current balun, or voltage balun is essentially frequency independent, the operation as a 0/spl deg/ power combiner or splitter is not. Instead, the isolation between the 0/spl deg/ and 180/spl deg/ ports is finite and frequency dependent. Moreover, the reflection coefficient at the sum port is nonzero and frequency dependent. These characteristics lead to the conclusion that while the equal-delay 180/spl deg/ power splitter/combiner is fundamentally frequency independent, its 0/spl deg/ counterpart is limited to operation well below the fundamental quarter-wave frequency of the constituent transmission lines. Full three-port scattering parameter representations, which are compatible with the calibration and analysis approach given in the CISPR 16-1 specification, are given for the three fundamental transformer and balun types derivable from the equal-delay hybrid: 1 the Guanella voltage balun, 2 the Guanella current balun, and 3 the 180/spl deg/ power divider or terminated hybrid balun, as specified in the CISPR 16-1 specification.