用Nullor构建理想电压源模型求解符号传递函数的方法

电路网络的符号传递函数分析技术在电路分析与设计中起着重要的作用。本文利用Nullor元件，构建了理想电压源的模型，扩展了节点分析法的应用范围，并且基于Mathematica强大的符号处理能力，设计出一种求解网络符号传递函数的节点分析法。该方法可以求解节点间含有理想电压源的线性时不变（LTI）系统中各种电路参数的符号传递函数。电路分析与设计实例表明，利用本文给出的方法所开发的符号传递函数求解程序，是电路分析和电路设计的有利助手。     

DQDB城域网暂态和稳态公平性分析

本文分析了DQDB城域网在大文件传输时的公平性。通过分析大文件传输时某一节点的性能及网络各节点的关联性,证明了网络经过一个暂态过程后将达到稳态,给出了各节点在稳态及暂态时的吞吐量、暂态过程长度的表达式。     

广义节点方程建立算法研究

通过引入由若干互连的无伴电压源支路及其端节点组成的广义节点,采用节点分析法和加减消元法,探究广义节点方程的建立规范和方法,建立了广义节点方程建立算法,解决了用节点电压分析法分析含有无伴电压源支路电路时所遇到的困难,确保了节点电压分析法的规范性和一致性,并可使所列节点电压方程尽量减少。理论分析和实例表明,这里提出的算法对于解决合有无伴电压源支路的电路具有很大的优越性。     

基于Matlab的电路节点分析法

在用计算机求解大规模电路时，多采用节点法分析。Matlab具有强大的矩阵运算功能，在电子技术中应用广泛。对用Matlab分析大规模电路时的模型建立方法进行了研究，并编写了相应的程序用于求解大规模电路中的电流和电压。结合一个实例，说明用Matlab分析大规模电路的方法。     

1985年上海铁道学院铁道运输自动化与通信专业硕士研究生入学试题及题解

试题名称:电路、信号与系统一、试求图1(a)、(b)和(c)所示电路中各电阻上的电压,电阻上消耗的功率,并通过计算电压源和电流源所提供的功率来确定各电阻所消耗功率的来源. (12分) 二、图2(a)和(b)所示电路处于正弦稳态,试用相量法写出图2(a)的网孔电流方程和图2(b)的节点电压方程.(12分)     

基于电压灵敏度矩阵的分布式配电网电压控制

随着我国分布式光伏的大规模发展,配电网电压的控制变得越来越重要。为了提高配电网中分布式光伏发电的负载能力,文中提出了一种基于电压灵敏度矩阵的配电网电压控制方法。该方法首先通过分析节点注入功率变化对节点电压的影响,构建关联各主节点有功功率和无功功率的电压灵敏度矩阵。然后依据电压灵敏度矩阵,充分利用分布式光伏逆变器的无功调节能力,将配电网的节点电压快速控制在工作范围之内。仿真结果表明,该方法可以有效降低分布式配电网在各种工作场景下的电压偏差,提高电压质量。     

电路分析的观察法和矩阵法的等效证明

回路电流法与节点电压法是电路分析的有效方法,而节点导纳矩阵Y_n,回路阻抗矩阵Z_l,节点源电流向量I_Sn,回路源电压向量U_Sl是在使用这两种方法时定义的矩阵与向量。然而,教材后文在引入两种方法的矩阵形式时,再次对上述矩阵与向量进行了定义。本文利用矩阵展开法,证明了两种定义的等价性,并给出含有耦合电感及受控源时,上述矩阵与向量的计算方法。     

基于基准源提出的一种环路稳态分析方法

提出了一种便捷的环路稳态分析仿真方法,辅助多环路多稳态系统设计,进一步确保系统正常稳定工作的可靠性。该环路稳态分析方法通过在系统关键节点添加测试激励源,直流扫描仿真测试源的静态电流,分析系统多个稳定工作状态具体情况。以基准源多态问题为例,使用该环路稳态分析方法从理论定位,仿真验证到流片测试,解决了该基准源多态问题,全面证明了该环路稳态分析方法的正确性和实用性。     

LCoS灰度控制电路的研究

提出了一种硅上液晶(LCoS)灰度控制电路的设计方案,分析了液晶的电光特性,给出了LCoS 256级灰度和参考电压源各部分电路的实现方法.用Cadence环境下的Spectre仿真工具对参考电压源系统进行了仿真,给出了电路的仿真结果,验证了设计的正确性.仿真结果显示,参考电压源的4个输出口能够分时输出8个不同的参考电压,实现了参考电压源输出口的时分多路复用,满足了设计要求.     

LCoS芯片集成可编程参考电压源的数字电路设计

介绍了LCoS显示系统的工作原理,分析了可编程参考电压源中各部分电路的功能和液晶显示器的电光特性,给出了可编程参考电压源的总体框图.用Verilog硬件描述语言完成了参考电压源数字电路的设计和编码算法,并用Cadence NC-Verilog对电路进行了仿真,给出了电路的仿真结果.用此算法设计的电路能够实现参考电压源输出口的时分多路复用,减小系统电路版图面积,降低系统的功耗.仿真结果显示系统电路的输出符合设计要求.     

A methodology for large-scale R&D planning based on clusteranalysis

A decision-support approach to large-scale R&D planning is described. A quantitative model based on three analytical tools, the interaction matrix, hierarchical cluster analysis, and the Boston Consulting Group (GCG) strategic planning matrix, is used. Results of the model are used to determine the number of R&D program areas, the technological focus of each R&D program area, and the relative allocation of resources to the R&D program areas. Traditional optimization techniques for R&D planning often generate solutions without allowing for the judgement, experience, and insight of the decision maker. The decision-support approach presented supports, rather than replaces, the judgement of the R&D planner by using a graphic display of the relative position of technology clusters, and by using an interactive and iterative approach to problem solving. An application to R&D program planning for Virginia's Center for Innovative Technology's Commercial Space program is presented     

关于正弦稳态功率传输的讨论

正弦稳态最大功率传输定理是电路教学中的重要内容。本文讨论了在给定电源内阻抗和负载阻抗的情况下,通过在电源和负载之间接入一个二端口网络,以达到实现阻抗变换的目的,从而实现负载阻抗获得的功率最大;推导了在电源和负载之间接入由动态元件构成的对称互易二端口网络实现负载功率最大的传输矩阵计算公式;并对二端口网络的结构作了进一步的说明。上述讨论结果可供讲授电路课程的教师参考。     

C/C++源代码静态检测系统的设计和实现

为了检测出C/C++源代码程序中常见的运行时错误,设计了一个静态检测系统。该系统通过词法分析、语法分析、语义分析来获取程序的语法树。然后系统的检测程序将会分析语法树的每一个结点,判断结点中的属性信息是否存在错误。创新点在于语法树数据结构和检测程序的设计。通过检测程序对结点的属性值的分析,能够检测出C/C++源代码程序中出现的数组越界、指针错误、字符串函数错误,内存泄露等问题。     

A Fourier analysis for a fast simulation algorithm [for powerconvertors]

A powerful discrete modeling approach to the simulation of a switching converter that has appeared in power electronics literature over the last several years is briefly reviewed, and some desirable traits for its matrix exponential subroutine are discussed. The key result is a systematic and generic Fourier analysis that operates on the steady-state solution as provided by a discrete model. The Fourier analysis algorithm was tested on a phase-controlled parallel-loaded resonant converter which is useful as a fixed-frequency low-distortion AC source. Three verifications of the algorithm were made: a phasor analysis, an alternate closed-form analysis directed specifically to the problem at hand, and an analysis using experimental data. The performance of the algorithm was good for the case considered     

基于I2C总线的大型开关矩阵设计与实现

介绍了一种基于I2C总线的大型开关矩阵结构及其功能,给出了其测试电路结构组成及控制电路组成.根据测试流程,给出了主机控制程序设计及部分实现代码,并针对开关矩阵硬件构成,分别给出了各个组成部分的固件程序代码.该系统为低成本、便携化、通用化、多通道测试方案提供了一种新的实现手段.     

A Technique for the Analysis of Repairable Redundant Systems

A new analytical technique is presented for evaluating the steady-state performance of large repairable systems which cannot be described in terms of series-parallel subsystems. The method, which is based on a novel combinatorial algorithm, is used to calculate the frequency of failures and expected failure durations at each node in networks of repairable devices. The networks may have multiple input and output nodes, but the uptimes and downtimes of the devices in the network are assumed to be exponentially distributed and independent. To demonstrate the usefulness of the technique for large-scale networks of general configuration, the solution of a sample problem using a pilot computer program is also included.     

PC programs for engineers

Two programs are described. The first is a program for digital signal processing that provides for a wide range of input signals and uses the fast Hartley transform for conversions from the time domain to the frequency domain and vice versa. The desired input waveforms can be created internally by the program or imported from an appropriate disk file. The data obtained can be stored in a file as well as displayed on the screen. The second program extends the use of the PC from performing algebraic operations on matrices to the case in which the matrix elements are complex numbers. It provides a compact, easily applied tool for performing sinusoidal steady-state computations and other operations requiring the manipulation of arrays of complex numbers. Examples of the use of both programs are given     

Steady-State Availability of k-out-of-n:G System with Single Repair

This paper presents a solution and computer program for steady-state availability of a k-out-of-n:G system with single repair. Techniques and methodologies are commonly treated in text books to solve one and two element availabilities. This paper provides both the solution for k-out-of-n system availability and a FORTRAN source program for calculating the availability. The managers of mass transit and computer systems can put n elements on line with the assurance that, on the average, at least k elements will actually be available to complete the mission.     

程序代码相似度度量中词法分析器的设计实现

针对程序代码相似度度量中的词法分析问题,提出了一种基于语言词典的词法分析器的设计和实现方案。通过对程序源码进行预处理,将其转换为一个字符串,然后对该字符串逐字符进行分解,得到构成源代码的每一个标识符Token,并判断其类型,实现对程序源码的词法分析。实验结果表明,该方法能有效分析程序源码的词汇构成情况。     

Carrier-Based Modulation Technique for Matrix Converter

This paper presents a carrier-based modulation method for a matrix converter. By using the offset voltage and changing the slope of carrier, it is possible to synthesize the sinusoidal input currents with the unity power factor and desired output voltages. The proposed method is equivalent to the so called space vector pulsewidth modulation method. The proposed method uses a new point of view to understand the matrix converter modulation method such as the voltage source inverter (VSI) modulation method. Using the proposed method, this paper presents the two-phase/three-phase modulation method and dynamic/steady-state overmodulation method for the matrix converter. These methods are well developed in the study of a VSI. By the proposed steady-state overmodulation method, it is possible to synthesize the fundamental component of output voltage to be equal to that of input voltage at the cost of some distortion of input current. The feasibility of the proposed modulation method has been verified by a computer simulation and experimental results. These results show that the proposed carrier-based modulation method can be implemented easily without any tables. It can be used for the application where a higher voltage transfer ratio is essential