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。     

双口网络特性参数转换及网络函数计算程序

在双口网络分析设计中,为了方便,常常根据实际情况选用某种参数表征网络特性。例如,一般用 A 参数描述链联双口网络特性,用 Z 参数描述串联双口网络特性,而在需要实际测量时,又采用实验参数描述等等。这样,在整个分析设计过程中,往往需要进行不同参数间的等效转换。一般说来,这种转换计算属于相量运算,用人工方式进行时,不仅计算繁复、精度低,而且很容易出错。此外,在研究接有电源和负载的双口网络特性时,其网络函数计算也有类似困难。应用微型计算机解决上述问题是很方便的。本文介绍一个用于双口网络特性参数转换及网络函数计算的计算机程序。根据网络理论,如图1所示双口网络的 Y 参数、E     

基于Simulink的钻井信息传输通道特性仿真

为利用钻杆有效地随钻传输地面与井下之间的数据。本文应用声波无缝传输模型将任意钻柱组合分解为单个声波无缝传榆模型级联方法．根据某单个典型钻具无缝传输模型系统函数的S参数和声波钻井信道的传输特性,推导了在信道通带内某一频点等效传输函数．在Simulink环境下仿真了该S参数的等效传输函数,并仿真了将双口网络S参数构成单钻具系统函数进行级联构成多个钻具的联接的系统函数。最后根据双口网络参数性质,多钻具级联的系统函数等效为各级T参数的连乘,将S参数转化为T参数,得到多个相同钻杆级联后的模型系统函数特性,仿真结果将对随钻声波传输仪器的方案设计提供有力的技术支持。     

关于线性无独立源双口网络串并联接的有效性讨论

对于线性无独立源双口网络串并联接(分为串联、并联、串并联和并串联)成复合双口网络的有效性问题,现行国内教材(包括译成中文的有关外国书籍)中论述很少,一般只提及检验方法而不说明其原理。只知怎么做,不知为什么该这样做,教师心中不踏实,学生的疑惧心理也难以排除。本文的讨论作为教与学的参考,或许有所裨益。讨论以串联复合双口为例子说明联接有效条件的来由,以并联复合双口为例子证明联接有效条件的充分性和必要性。限于笔者水平,不妥与错误在所难免,恳切读者及时指正。     

嵌入式多层多域光网络路由及控制器设计(本期优秀论文)

提出一种光网络路径计算及连接控制专用系统的设计和实现方法.搭建基于该设计的实验平台实现了在多SDH及OTN域光网络之上的跨域连接调度、生存性策略等多层多域光网络互连互通功能,并满足实时性、可靠性、低成本等要求.     

自由空间非对称与对称混洗网络的拓扑等价

为了解决非对称Omega Omega混洗网络的拓扑等价问题,提出一种新的方法.对Omega Omega网络的左或右半部分节点对应的二进制位进行逆操作,将取逆操作后得到的混洗网络与另一半混洗网络串联,中央级间的连接根据具体的规则采用简单蝶互连或复杂蝶互连方式,从而将非对称的Omega Omega混洗网络转变为对称的Omega-1 Omega或Omega Omega-1混洗网络,最后得到它们之间拓扑等价.     

基于Matlab符号计算的双口网络分析

双口网络的分析是"电路分析"的重要内容之一,其中涉及大量的公式推导与计算.本文以电路中的双口网络为例,利用Matlab的符号计算功能,推导双口网络各参数间的关系,分析具有端接的双口网络,以此说明符号计算在电路分析中的应用.将符号计算引入电路分析可提高学生的学习兴趣和课堂教学效果.所编程序及计算结果可供在电路分析的教学中使用.     

基于S参数的RC内连网络约简

本文介绍一种ＲＣ互连网络化简的算法。利用Ｓ参数矩阵表示互连网络并对互连网络进行约简，使算法具有可扩充性。本文给出了用Ｃ语言实现该算法和用软件进行化简后的电路以及化简前后电路的模拟结果。模拟结果表明，基于Ｓ参数的ＲＣ内连网络约简算法是正确的。化简前后的模拟结果基本吻合。     

混洗网络中光开关矩阵研究

基于偏振控制技术,利用偏振光分束器和位相型空间光调制器构建1×2和2×1的节点开关单元,节点开关单元各端口间按照特定的映射规则和连接关系以光纤实现互连,从而得到一种新型的4×4光开关矩阵.该 4×4光开关矩阵利用位相型空间光调制器对信号光偏振态的控制实现路由,通过对其各输入端口光信号路由状态的分析表明,它可以完成信号光点对点的全排列无阻塞的输出与交换,同时,还具备部分的多点组播功能.该矩阵开关具有交换速度快、插入损耗小、串话低、性能稳定等特点,对于构建大规模的光互连网络具有一定的帮助.     

复合多端口网络的参数矩阵计算

一些电路教材对二端口网络的连接方式进行了介绍并给出复合二端口参数矩阵的计算方法。多个二端口的任意连接可以构成复合多端口网络,其参数矩阵也可以由构成它的二端口网络的参数矩阵表示。本文类比了电路网络中的关联矩阵,建立描述二端口和复合多端口关系的端口关联矩阵,并利用二端口的特性和串并联的特点,给出了求解复合多端口网络参数矩阵的新方法。     

关于互易二端口网络互连的讨论

互易电路及二端口电路互连是电路课程教学中的重要内容。本文讨论了互易二端口电路互连后总二端口电路的互易性,给出了一般性结论及证明,即互易二端电路互连后如仍满足端口定义,则互连后的总二端电路仍然是互易的。对于对称二端电路,也有类似的结论。本文的讨论对电路课程的教学具有一定的参考价值。     

群论在网络理论中的应用研究

本用群论研究了双口网络集合，双口理想换器与器件的集合，２ｎ端口理想变换器和器件的集合。     

二端口传输参数测量及互易性对称性导出

针对现有教材在表述二端口传输参数时由其他参数推导而得的情况,讨论了二端口参数的测量方法。针对现有教材在叙述采用传输参数表达的互易或对称二端口电路性质时基于其他参数形式而非传输参数形式本身而导出的情况,讨论了基于传输参数本身的二端口互易性或对称性的导出方法。本文的讨论表明,二端口电路VCR的传输参数表达形式是独立于其他参数表达形式的。     

Efficient Technique for the Cascade Connection of Multiple Two-Port Scattering Matrices

There are several practical applications in microwave engineering that require the cascade connection of multiple two-port scattering matrices. Many microwave devices are analyzed by segmenting the structure into small building blocks (steps, resonators, lines, etc.) that are characterized by means of the generalized scattering matrix. In order to obtain the reflection and transmission parameters of the entire structure, the scattering matrices of all the building blocks must be cascaded. Traditionally, the conversion of the scattering matrices to ABCD or T matrices has been used in order to perform the cascade connection. An alternative to this procedure is to perform a recursive connection by pairs of the scattering matrices. In this paper, we present a new technique for the efficient cascade connection of N monomodal or multimodal scattering matrices that reduces the computation time by 35% when compared to the cascading by pairs, and by 75% when compared with the use of ABCD matrices.     

Cascade of simple commensurate uniformly distributed RC four-port unit elements

The simple commensurate URC? four-port unit element is defined, and the transfer matrix for a cascade of these elements is derived. It is shown that certain terminal connections will produce a two-port network with two short-circuited admittance parameters (transfer and one driving-point) which are rational in the normalised URC? complex frequency variable t = tanh ?s. The real-frequency transfer response is investigated, and typical responses for networks containing two elements are presented.     

A Generalized Design Technique for Practical Distributed Reciprocal Ladder Networks

A generalized design approach is presented for ladder networks consisting of a cascade of constituent two-port networks connected by short lengths of transmission lines. The design is made possible by the derivation of simple equations which define the inverter impedance and associated reference planes of any passive lossless reciprocal two-port. This enables the general ladder network to be equated to a prototype network at a reference frequency. An example is given of the design of a coaxial low-pass filter where fringing capacitances are compensated automatically.     

关于端口总功率有条件满足叠加性的讨论

本文讨论了线性无独立源二端口和多端口网络的功率叠加性问题。指出,在网络自身满足一定条件,并且端口所接独立电源符合某种要求时,网络消耗的总功率满足叠加性。用网络的端口参数之间的关系描述了这些条件。端口所接的独立电源区分为三种情况：全部为电压源；全部为电流源；部分为电压源,部分为电流源。举例验证了第三种情况下的功率叠加性。这些内容可以扩展人们对电路叠加性质的认识。     

Note on Impedance Transformations by the Isometric Circle Method (Correspondence)

The isometric circle method is a graphical method of transforming a complex quantity by the linear fractional transformation. It has recently been applied to impedance transformations through bilateral two-port networks. The purpose of this note is to show the connection between the isometric circle method and another graphical method called the "triangular" method, and also to present a useful formula for reflection-coefficient transformations through bilateral, lossless two-port networks.     

一种新的RC双口网络综合方法

本文提出了一种新的网络综合方法。该方法解决了单端接RC负载和一端接RC负载,另一端接RL负载的RC双端口网络的实现问题。     

Noise parameters of SIS mixers

It has been shown that low-noise receivers can be constructed at millimeter wavelengths by using mixers containing superconducting tunnel junctions as the nonlinear elements. This is possible because of both the low intrinsic noise of these devices and their potential for high conversion gain. Here, the quantum theory of mixing is used to derive the full-noise parameters and small-signal parameters of sinusoidally pumped SIS (superconductor-insulator-superconductor) junctions. These are then put into a form that allows the theory of two-port linear networks to be brought to bear, allowing calculation of such useful parameters as minimum noise temperature, optimum source impedance, available (or exchangeable) gain at minimum noise, and stability factor. These quantities are properties of the pumped junction that do not depend on the source or load impedance, but do depend on the terminations at the image and harmonic sideband frequencies. The harmonic sidebands are taken to be shorted, and the image termination dependence is studied. Numerical results are presented for both ideal (BSC theory) and practical (measured current-voltage characteristic) junctions. The noise parameters of the cascade connection of an SIS mixer and a (noisy) IF amplifier are considered, leading to a specification of the optimum coupling network between the two. It is noted that the SIS mixer is usually not unconditionally stable, but that oscillation can be avoided by careful design of the IF coupling network