SPICE applications to an undergraduate electronics program

A plan is presented for integrating SPICE (simulation program with integrated circuit emphasis) into an undergraduate electronics curriculum. Three design projects for students are described: a network theory project, an analog electronics design course, and a senior thesis project. In the first project used in a first course on network theory, the emphasis is on simple programs that can extend basic techniques (such as Thevenin's equivalent circuit) to cases where hand analysis is long and tedious. In the electronics course, the application of the bipolar-junction transistor and field-effect transistor is more clearly understood by the student when he/she constructs an analog amplifier according to a given set of specifications. Creativity is encouraged, since the design of the amplifier is flexible as long as the specifications are met. In the senior thesis project, SPICE, along with other computer design packages, enables the student to analyze and modify a project before it is constructed. This saves valuable construction time and allows for a more thorough theoretical analysis     

基于MSComm和队列技术的LabVIEW数据采集系统设计

针对传统LabVIEW数据采集系统中串行通信实时性不高和程序运行效率有待提高的现状,提出了一种基于MSComm和队列技术的LabVIEW数据采集系统设计方案。该方案以DSP作为下位机控制核心,实现了模拟前端的数据采集,采用PC机作为上位机,基于LabVIEW 2012开发环境,设计了上位机应用软件,实现了模拟前端采样数据的处理、存储、显示及统计分析等工作。实践结果表明,该设计方案具有运行稳定可靠,硬件接口简单、易用,软件编程简单,易于维护和扩展等优点。     

Predicting Control Performance of Residential Heating Systems with an Analog Computer

A properly designed residential heating system must provide homeowner comfort under a broad range of operating conditions. Doing this with an economically priced system requires knowledge of the many variables affecting system performance. A typical heating system including the house, furnace, heat conveyance, and thermostatic control has been simulated on an analog computer facility. By varying computer inputs to reflect changing outdoor weather conditions, house construction, type of heating plant, and occupancy, system performance with different types of controls can be readily evaluated. This type of computer analysis facilitates early consideration of component design variations aimed at achieving optimum performance with minimum cost.     

Computer Methods Course for Engineers

With the advent of the computer, engineering education had to be altered to accommodate the use of the computer as an engineering tool. Being aware of this need, the Electronic Engineering Department at Monmouth College, West Long Branch, N. J., has developed and is experimenting with a course which prepares students to use both the analog and the digital computer in engineering analysis. The content, purpose, development and laboratory facilities utilized in this course are described. The principal emphasis in the course is on the use of the computer as a tool in analysis and design.     

关于量化和A/D-D/A的讨论

数字、量化、量化效应、模拟、模拟量、A/D转换、D/A转换是计算机控制工程和控制理论上的常见概念.静心推敲,发现有不少流行性的误解.例如：不是“量化”而是截尾或四舍五入,不是“数字量”而是bit量,不是“模拟量”而是物理量等.     

The SDS-92/TR-48 Hybrid Computer Sytem in Engineering Education

This paper describes how an SDS-92 digital computer has been connected to a TR-48 analog computer by appropriate interface equipment to permit the high information rate capability of the analog computer and the precision of the digital computer to be combined into a practical hybrid system. The value of the hybrid computer as an educational tool is discussed. Some problems solved on the hybrid computer by students of the hybrid computer course at the Department of Electrical Engineering, University of Iowa, are illustrated.     

Personal computer support for teaching analog filter analysis anddesign

A computer-aided design (CAD) program for analog filter synthesis, FILTER, which enhances the effectiveness of teaching analog filter analysis and design, is described. Initially, FILTER was developed to support related courses in the Department of Electrical Engineering at the University of Wyoming, but eventually its scope went beyond that intent. This program very effectively fills the gap between textbooks, and professional programs, which are not designed for educational use. Essential features of an educational computer program in this field are considered and these requirements are fulfilled in FILTER. The paper can serve as a guide for the reader to launch FILTER and browse through it for the first time with almost no effort     

Controllable analog emulator for power system analysis

This paper details the development of a controllable analog emulator for power system analysis. The emulator consists of reconfigurable analog hardware for power system emulation and a digital computer, along with associated software, for configuration, control, calibration and data acquisition. The analog hardware is fully controllable via the software interface. System parameters, initial conditions, integration, faults and contingencies can be created or altered via the software with no changes or manual intervention to the analog hardware. This advance overcomes one of the larger drawbacks of older analog computers, which was the need for manual configuration and calibration. The emulation methodology is presented in this paper as well as power system modeling, both theoretical and in analog hardware. The software interface and control is also presented. To validate the operation of the emulator two examples are shown from a prototype emulator. The first being a steady state power flow solution, the second computes the critical clearing time of a generator fault for transient stability.     

Modal reduced dynamic equivalent model for analog type power systemsimulator

Analog type power system simulators are playing important roles in cases where real time dynamic studies are required. Power system reductions are more important in analyses using an analog type simulator than a digital computer due to facilities limitations. This paper describes a modal reduced dynamic equivalent model which was developed for an analog type power system simulator to provide power system reductions. The model is implemented by using a modal analysis approach based on a digital type synchronous generator model. In simulator tests on a 28-machine power system, the model is judged to be useful for representing subsystems to be reduced in an analog type simulator     

Application of Desk-Top Computers as Aids in Teaching Mathematics

Some basic, unpretentious analog circuits are presented which may be useful in demonstrating mathematical concepts introduced at the senior high and college freshman levels. The analog computer is used as a picture-drawing device. How it operates is not emphasized. These circuits have been used several times in presentations made to groups of teachers, and should be of particular interest to those involved in teaching algebra in high school and college freshman classes.     

An Analog Prepatch Panel for the Two-Dimensional Quasi-Linear Differential System

This paper describes a prepatch panel for a desktopsize analog computer which prewires the computer to simulate a large class of two-dimensional quasi-linear differential systems. Examples are given to show that once such a system is written in the proper mathematical form, its computer simulating can be accomplished directly from the panel without having to first draw the usual analog wiring diagram.     

Continuous recording and stochastic analysis of PD

We describe the design and use of a digital partial discharge (PD) data recording system capable of continuous real-time recording of PD pulse trains. The recording system consists of a custom two-channel PD digitizer coupled to a personal computer via a 10-bit parallel interface. The digitizer is under software control with the resulting data being stored in binary files on the computer's hard disk. The stored data subsequently are subjected to stochastic analysis using appropriate computer software. Because all data are retained and the computer provides the desired stochastic analysis of data files, the new system is well suited to investigate non-stationary PD behavior such as encountered in aging studies. By way of illustration, the new system was used to determine the time-varying stochastic behavior of ac-generated PD from point-to-dielectric gaps in air where the insulation material was cast epoxy with aluminum oxide filler. The results confirm and extend previous measurements made with an analog stochastic analyser. With these sample results, we demonstrate how the system allows detailed stochastic analyses not possible with data obtained from existing conventional PD measurement systems     

用“洪图”实现单片机实验的动态模拟演示

讨论了利用“洪图”多媒体编著系统实现单片机实验的动态模拟演示的方法，给出了单片机实验多媒体教学软件的总体设计框图、实验结果动态模拟演示的程序框图以及实现动态模拟演示的部分程序。结果表明，利用“洪图”开发多媒体应用软件，不仅可以缩短软件的开发周期，还可以使应用软件具有较大的灵活性。     

Novel applications of SPICE in engineering education

The author presents several novel applications of the SPICE circuit analysis computer program which should be of use to engineering students of various disciplines. Attention is directed to an implementation of SPICE for the MS-DOS operating system environment, named PSPICE. Three specific examples are presented. The first example shows a method of simultaneously displayed several parametric solutions. The second example demonstrates a method in which PSPICE simulates an analog computer. The third example illustrates the solution to a nonlinear differential equation     

Theory, simulation, experimentation: an integrated approach toteaching digital control systems

This paper discusses the approach adopted by the authors for teaching an undergraduate course (lecture and laboratory) in digital controls. Theoretical material is developed in the lecture concerning the application of direct digital control (DDC) to an analog bench-scale system consisting of a DC motor and tachometer. A simulation of the closed-loop control system with embedded digital controller is developed and run by the students using the TUTSIM dynamic simulation language. Finally, students perform a laboratory experiment in which they write a program to control the actual system using a personal computer and inexpensive interface card. The combination of hands-on experience and computer simulation with the more traditional, theoretical lecture material provides a well-rounded learning experience that better prepares the students to implement digital control systems in the real world     

Polarization-induced distortions in optical fiber networks withpolarization-mode dispersion and polarization-dependent losses

We review the formalism required to investigate the combined effects of polarization-mode dispersion (PMD) and polarization dependent losses (PDL) in optical fiber networks. The combination of PMD and PDL may lead to anomalous dispersion, which is not correctly described by a direct application of the Jones matrix eigenanalysis (JME) method. This calls for a careful assessment of PMD measurement methods in the presence of PDL. We also present a theoretical analysis of distortions in analog transmissions, and computer simulations of digital transmissions. These show that distributed PDL increases the power penalty of the transmission more than lumped PDL at the end of the channel     

Microcomputer-Based Controls for Continuous Casting

The continuous casting of steel eliminates many processing steps, thus allowing savings in time, energy, and processing costs. In this process a moving strand of steel is partially solidified in a water-cooled mold and subsequently cooled to complete solidification by intensive-cooling water sprays. Control of the cooling sprays is complex, requiring distributed control techniques, which are not readily implemented by analog means. Therefore, digital computer control systems have been developed for this purpose. In the past these systems have used a minicomputer in a supervisory control mode to provide optimum water-flow setpoints to conventional proportional plus integral analog controllers. This approach has given satisfactory results, but initial hardware and software costs have been high, and maintenance requirements, particularly in the computer/controller interface hardware, have been excessive. US Steel is currently testing a microcomputer-based control system which has the potential for resolving these problems. This system provides all the control features normally used as well as direct digital control (ddc) of cooling water flows, thus eliminating the need for analog controllers. Experience to date indicates that this new approach will provide increased reliability along with a significant reduction in equipment and maintenance costs.     

Experimental validation of a computer model simulating an impulsevoltage distribution in HV transformer windings

A number of computer models have been recently proposed for simulation of the impulse voltage distribution in the winding of power transformers. Some of these models can predict the winding behavior at high frequencies, some other were developed as a practical tool for designers of lower voltage transformers. The time and expenditure put in development of these models should be balanced by a similar effort to check the model validity. Such checks consist of a comparison of the predicted voltages to the actually measured ones. With the advent of high resolution, fast digital recorders and signal processing techniques, this validation can be performed to a much higher accuracy and completeness than the conventional comparison of analog oscillograms to simulated graphs. The paper presents such a validation technique applied to a computer model of a transformer winding     

Meeting the analog world challenge. Nyquist-rate analog-to-digitalconverter architectures

To bring digital processing and its benefits to bear on real-world applications, the analog signal of interest must be translated into a format a digital computer can utilize. This is the function of the analog-to-digital converter (ADC). After processing by a digital computer or digital signal processor (DSP), the resulting digital stream of information must be returned to its analog form by a digital-to-analog converter (DAC). The methods by which a digital code is generated within the ADC are diverse. We introduce three popular Nyquist-rate ADC architectures used today: the counter ramp ADC, the successive approximation ADC and the flash ADC     

数字模拟技术分析及微机通道的设计

Ａ／Ｄ和Ｄ／Ａ技术是计算机实时控制系统中的重要组成部分．外界的模拟量（如电压、电流等），只有经过Ａ／Ｄ转换为数字量计算机才能接受，加工、处理；同时，只有经过Ｄ／Ａ转换才能使计算机控制各类伺服系统（如调压、调温等）以达到实时控制之目的．根据实际系统的要求和Ｄ／Ａ、Ａ／Ｄ芯片建立微机通道，在特定接口的基础上用软件支持这种转换的完成，同时，给出了一种用Ａ／Ｄ，Ｄ／Ａ进行正道变换的实用系统．系统的设计方法对建立各自模拟系统的读者有一定的借鉴和启迪作用．