Showing papers in "IEEE Transactions on Education in 1969"

The Fast Fourier Transform and Its Applications

Abstract: The advent of the fast Fourier transform method has greatly extended our ability to implement Fourier methods on digital computers A description of the alogorithm and its programming is given here and followed by a theorem relating its operands, the finite sample sequences, to the continuous functions they often are intended to approximate An analysis of the error due to discrete sampling over finite ranges is given in terms of aliasing Procedures for computing Fourier integrals, convolutions and lagged products are outlined

Generalized Clarke Components for Polyphase Networks

Abstract: This paper deals with the generalization of the Clarke components to polyphase current and voltage systems. Two definitions are proposed and their relative merits are discussed. It is shown that the second definition is to be preferred, since it is not only valid for completely symmetrical networks, but also for networks containing elements with only partial symmetry, such as the stator of an electric machine or an untransposed polyphase transmission line. The considerations of this paper may be used in the classroom to provide the student with a complete understanding of the principles of the decomposition techniques of polyphase quantities.

A Regional Approach for Computer-Aided Transistor Design

Abstract: A regional approach to transistor design is presented which makes possible the determination of transistor gain hFE for any transistor (doping profile specified) operating at any given values of emitter current IE and collector-to-emitter voltage VCE. This approach extends the classical diffusion theory of transistors to include conductivity modulation, voltage-controlled base motion, and current-controlled base motion (base widening). Due to the simplicity of this technique, time-sharing computer techniques were used. This allowed for user interaction, making this approach very attractive for education as well as design. The regional approach is a likely candidate for satisfying the needs for the device designer (it contains device performance versus doping profile), the circuit designer (it allows determination of equivalent circuit models from knowledge of the electron and hole densities throughout the device), and the academic world (it is simple and physical). It is anticipated that the regional approach will allow engineers to develop a "feel" for transistor behavior under wide ranges of operating conditions.

A Computer-Oriented Sophomore Course on Nonlinear Circuit Analysis

Abstract: This paper describes the philosophy, application, and implementation of a collection of FORTRAN IV computer programs currently being used in a sophomore course on nonlinear circuit analysis at Purdue University Since these programs were developed from the education rather than the user point of view, some of them were deliberately designed in the form of a series of subroutines, and were stored in a common disk file These subroutines and programs are used to analyze a large class of nonlinear electronic circuits such as waveshaping networks, multivibrators, time-base generators, etc Since the computer is used to take over only the nonconceptual but otherwise very time-consuming task, the students were found to be much more receptive and motivated in learning new concepts The results reported in this paper are based on the experiences and reactions of approximately 150 students using the batch-processing mode A short description, however, is also given on a forthcoming experiment to be conducted at Purdue University on the merits of using an on-line graphic display console

Applying Audlio Tutorial Techniques to Laboratory Instruction

Abstract: In the senior communication theory course at Purdue University, instructional material which was formerly handled in a lecture-type preparation session is now being presented individually to students by means of audio tape recordings. Features of the audio tutorial method of instruction are discussed, with emphasis on the advantages and flexibility the method affords in laboratory instruction. The interplay between taped material, written notes and instructor activities is also discussed. Information for those interested in obtaining a sample audio tutorial tape is given at the end of the paper.

New Considerations in Teaching Switching Theory

Abstract: In this paper some aspects of the relation between the state of the art and the way of teaching in the field of switching theory are described. Some critical comments and suggestions concerning the contemporary way of teaching switching theory are presented.

Logical Instruments for Teaching Logical Design

Abstract: A way of teaching combinatorial logic is presently based on experimentation with physical models of logical relations ("logical instruments"). The Marquand chart [7] originated in 1881 is described and discussed. A graphical representation of a Boolean function on that chart is processed by experimental application of "implication masks." As an example of such a processing, the paper describes the construction of a minimal ??-form of a given Boolean function (by respecting DON'T-CARE conditions). The main part of the minimization algorithm is based on a sufficient condition of extension (of the expression (9) towards the minimal), which is satisfied if a certain "necessary condition of extension" does hold and if a certain "sufficient condition of exclusion" does not. To save processing time, a weight is assigned to each point on the chart where the Boolean function must be 1 (true). Then the minimization algorithm is applied, with a preference to points with smaller weights. Logical punch cards are used as a logical instrument for experimental evaluation of weights.

On the Frequency Response of Sampled-Data Systems

Abstract: Earlier work on sampled-data theory has extended the powerful technique of frequency response analysis to discrete systems. It is shown in this paper that the development to date has been inadequate in explaining the behavior of sampled systems under sinusoidal excitation. For purely discrete systems, replacing s with j? in Laplace and Z forms is satisfactory. However, for discrete-continuous systems, a more complete analysis is necessary. In the present work, impulse sampling is considered as a suppressed carrier modulation process where input sinusoidal components appear as sidebands about the sampling frequency and all of its integer multiples. Thus, signal behavior at the output of continuous elements may be interpreted in terms of these spectral components. This approach provides a deeper insight into the sampling process and raises some interesting questions about the meaning of frequency response.

The Essential Focus of Engineering Education-The Individual Student

Abstract: This paper presents the radical view that training manpower to satisfy the needs of industry or government is not the purpose of engineering education. Rather, the focus is the individual student, his needs, his development, his fulfillment. Often the needs of the individual are not compatible with the needs of the corporation or of government; in such cases the latter should yield. The curriculum should be designed with this outlook.

Black-Box Models for Linear Integrated Circuits

Abstract: The paper presents a general approach to the modeling of linear integrated circuits for computer-aided analysis in the frequency domain. The modeling is done through black boxes whose internal details are ignored and which are characterized only at their external terminals. Lumped and distributed, ideal and experimentally characterized multiterminal devices can be handled. The mathematical characterization is the indefinite admittance matrix. The implementation of the methods discussed is very simple, since no topological matrices are required. The method lends itself to analyzing large circuits by tearing them and then reconnecting the pieces. The method has been implemented in a program entitled BELNAP. A transient counterpart BELTIP and a design program IMPROVE have been in use by designers at Bell Laboratories for some time. An example circuit is solved in detail in the paper using BELNAP.

Circuit Models for Transformers

Abstract: Circuit models are developed from the physical behavior of transformers. The models contain passive elements and controlled sources which are directly useful in computer analysis programs, and which the designer can use a readily as transistor and vacuum-tube models. Linear models are developed for ideal and perfect transformers and for lossy transformers. A piecewise linear model is developed for saturable reactors. The development is carried out for the generalized n-winding transformer. The parameters of the circuit model are related to winding and core parameters to facilitate transformer selection and design.

Feedback Made Easy for the Undergraduate

Abstract: The increased use of linear integrated circuit amplifiers, which require feedback stabilization, has resulted in increased emphasis on teaching feedback techniques to undergraduates. This paper describes the method used at the Polytechnic Institute of Brooklyn to teach juniors how to analyze and design feedback circuits. We have found that these students can, after taking the course, analyze and design complicated feedback circuits, and test feedback amplifiers to determine (and adjust) the feedback present in an amplifier. The procedure presented in this paper is different from that used by other instructors in that we teach by example. Therefore, we do not use a block diagram approach which students have difficulty in relating to real amplifiers, but instead analyze and design actual circuits. Generality is sacrificed for clarity.

An Undergraduate Experiment in Signal Detection

Abstract: A simple but effective method for extracting periodic signals from noise is discussed, and experimental results of its implementation are given. This method (integration or storage), while only one of many ways in which such signals may be recovered from noise, has the advantage that it is easy to explain and to mechanize and thus is particularly useful in undergraduate signal theory courses and laboratory work. While certain of the components must be designed and constructed, most of the required equipment is readily available in the typical electrical engineering laboratory. The amount of design that is required can be varied and is consistent with undergraduate training. This allows the student to become involved in the planning and construction of the signal extraction system and should be helpful in stimulating the student's interest in random processes which continue to receive increased emphasis. Using the simple system described, it is possible to recover signals that are far below the noise level. A noise-to-signal power ratio of 100:1 presents no difficulties (provided the signal amplitude is sufficiently large) and limited results are given where the noise-tosignal ratio is 2500:1.

Computer-Aidee Control of Learning

Abstract: This paper presents the first computer-aided experiment on learning control which took place in Europe at the Faculte des Sciences de Paris. The teaching objectives, the level and the needs of the interaction (dialogue, open answers, feedback to the student) are described in the first part of this paper. Then the computer configuration is given and the technical solut'ions decided are discussed. The third part of the paper deals with the man-machine communication problem to which has been given great importance in the definition of the experiment. Some examples showing either the way the course is described and put into the system or the dialogue between the computer and a student are included in the paper.

Off-the-Shelf Black Boxes for Programming

Abstract: When a good circuit designer lays out a new circuit, he isolates those functions which are more or less self-contained and puts them in separate modules This not only has the advantages of simplification, flexibility, and easier maintenance, but it also enables the designer to take advantage of whatever off-the-shelf modules he can obtain A good programmer plans his programs the same way, dividing the operations up into black boxes called subroutines or procedures What black boxes should he expect to be able to get "off-the-shelf"? This paper deals with the type of numerical calculations an electrical engineer is likely to do, and describes fourteen kinds of computations for which he could expect to find black boxes to do the job In addition, ten kinds of computations are described for which he should not look for black boxes, as either they do not exist or they are hopelessly inadequate

Student Experience with Interactive Computer Programs for Linear Circuit Design

Abstract: Computer programs which allow interactionbetweenthe user and the machine in the design of linear circuits have been used by students of a graduate course in computer-aided circuit design. These programs, which enable the determination of circuit element nominal values to realize responses within specified constraints, have been operated both with batch processing and on-line through commercial time sharing utilities. Student experience with each mode of operation is described, including student reaction, relative gains through each type of operation, problems encountered, and exportability of this work to other schools and machines. Use of a typical interactive program for on-line design of an ac circuit is described in detail.

Circuit Design Application of the Michigan Terminal System

Abstract: The student use of batch on-line teletypewriter and graphical display facilities for circuit design at the University of Michigan is discussed. This includes batch use of GCA programs, teletypewriter use at the elementary algorithmic level, and display use for man-machine and automatic iterative design. Focus is placed on the economics of each level of design and on student reactions.

A Hybrid NASAP Module for Direct Design of Linear Dynamic Circuits

Abstract: This tutorial paper presents an introduction to the application of hybrid computation and optimization to the direct design of linear dynamic circuits using a simple optimization technique that does not require sophisticated computer programming. The chief merit of such simple techniques is that the user can easily verify the execution by stepping through the program in a manner that permits him to mentally check the logical decisions implemented by the optimization algorithm. This type of operation is economically feasible because of the development of a hybrid computer system which permits these techniques to be demonstrated at minimum capital cost.

Graphic Communication of Data from the Digital Computer

Abstract: Computer technology has provided a means by which large amounts of data may be accumulated and reduced to graphical form. The advantages of this type of computer output are considered and illustrated by means of two applications of particular interest to engineers. The utilization of computer drawn flow charts is discussed and some of the logical and technical problems involved are examined; characteristics of available programs are compared. The procedures of graphical data plotting and the available routines are then discussed and curricular applications are considered.

The NASAP Computer-Aided Circuit Design Program and Its Use in Undergraduate Education

Abstract: A description is given of the use of computer-aided circuit design programs in undergraduate education. The development of the NASAP program as a cooperative effort of universities and industry is presented. An example of the use of NASAP in the solution of an electromechanical problem is included.

Effective Teaching: Institutes for Engineering Teachers

Abstract: Concern for effective teaching in engineering appeared almost simultaneously with the inception of engineering education in this country, some 135 years ago, as seen in statements made by the first head of Rensselaer Polytechnic Institute. To place in perspective current efforts toward the teaching and training of engineers and to stress the significance of such endeavors, aspects of the evolution of efforts to foster and enhance engineering teaching are described. Pedagogical training for engineering teachers was proposed by persons such as early presidents of the Society for the Promotion of Engineering Education; but it was strong recommendations from that Society's four self-studies that appeared responsible for gradual development of formal programs. Under sponsorship of the American Society for Engineering Education (successor to the SPEE), the current "institutes on effective teaching" activities began with a series of two-week summer institutes, at Pennsylvania State University, during the summers of 1960-63. At the tennination of this series it was concluded that many more engineering teachers could participate through a number of regional institutes. Hence the ASEE promoted and developed a number of short-term institutes at various institutions throughout the country and, in 1967-68, inaugurated a system of Regional Institutes on Effective Teaching which are expected to become a regular and continuing part of engineering education and which should constitute evidence of the profession's historical concern for teachers "qualified for giving instruction...."

The Fourier Transform Asymptotic Behavior Theorem

Abstract: As a result of an increased utilization of the digital computer in Fourier analysis applied to engineering problems, the asymptotic behavior of the Fourier transform is becoming increasingly important. This paper presents a heuristic and detailed proof of a rather fundamental theorem bearing on this behavior, with the hope that this will engender greater emphasis on this technique in engineering curricula.

Linear Circuit Models Derived via Computer Optimization

Abstract: To make more efficient use of the computer as an aid in obtaining linear small signal circuit models, a method of successive approximation is presented and used to obtain a variety of circuit models. Several useful search strategies are presented and specific examples illustrate their use in deriving better approximations from an initial starting point. The relative merits of various search strategies are compared to furnish guidelines for future use. The modeling techniques are also applied to specific resistor and transistor characterization problems. The hybrid-pi model for the transistor is developed in a way which allows considerable flexibility in the inclusion of parasitic effects. A final example models a practical amplifier at frequencies up to UHF.

The Use of On-Line Graphical Computer Systems for Student Research

Abstract: The purpose of this paper is to point out the advantages and disadvantages of using an on-line graphical computer for graduate student research. The system itself consists of an IBM 2250 model I graphic console operating through IBM 360/40,/75, and /91 computers. It was hoped that this would provide an interactive graphical system permitting the student to solve his dissertation problems in a novel fashion. The experience gained in this endeavor and the methodology which the student might develop could prove to be even more valuable than the solution of the problem itself and would constitute an integral part of his thesis. The paper reports on the work carried out for a Master's thesis and for a Ph. D. dissertation. The former consisted of an attempt to solve nonlinear programming problems in n dimensions by searching for the optima on a CRT screen exhibiting contour lines and constraints in two variables, the others being varied by on-line control. The other application consisted of developing a simulation language allowing for on-line graphical displays and interaction, and applying this language to the design and analysis of a complex digital computer system consisting, in particular, of a variable number of time shared consoles. The results of this work clearly showed the convenience of an interactive graphic system while underlining the difficulties experienced in operating either with an inherently slow system or a powerful system slowed down by batch background operation.

Computer-Flavored Circuit Theory

Abstract: The objective in the courses described herein was to teach circuit analysis, optimization, and design in a way that recognizes the important role of computers, but does not become overpowered by the myriad subtleties and irrationalities of real-world computers. This paper discusses the author's experience in using existing interactive computer facilities to teach graduate and undergraduate circuits subjects, and suggests promising directions in which to go and not to go. Questions raised concern the role of omnibus circuit analysis programs, if any, how to teach numerical analysis without quite, time-sharing economics, and the use of a computer in teaching machine mode someday.

Partial Fraction Expansions with Repeated Poles

Abstract: Special methods are generally used to evaluate the partial fraction constants corresponding to the repeated poles of a proper fraction. Here it is shown by example that the normal method is easily extended to cover this situation; the procedure is useful pedogogically as an introduction to the Goldstone method.

A Simple ECAP Transformer Model

Abstract: A bridge is constructed between the concept of mutual inductance and available transformer data to enable the construction of simple ECAP transformer models.

Design of Digital Systems: The Parse-Implement Approach

Abstract: Presently the design of digital systems as treated in undergraduate engineering programs is restricted to one of two environmental levels, software or hardware, with little pedagogical effort directed at uniting these levels. This paper introduces the concept of a systems level of study at which environmental level considerations become special case treatments of a generalized design procedure. This procedure is called the parse-implement (systems level-environmental level) design approach. The features of this approach are outlined with the presentation of six fundamental considerations of digital system design within the context of the systems level language. The applicability of this approach is demonstrated by means of an example design problem for which both a hardware and a software solution are generated. The usefulness of this approach as a means of teaching design is also demonstrated by these examples.

A Compiler Level Program for Teaching Digital Systems Design

Abstract: Instruction in the concepts as well as the design techniques of digital systems, including computers, can be considerably facilitated by demonstration. The hardware equipment required for such demonstration in a comprehensive course covering many systems and techniques may be very expensive. One solution to the cost problem is to simulate the systems to be studied using programs written for a general purpose digital computer, which normally is readily available. The instructional aids described are based on systems whose simulation programs are written in a compiler language as well as a language specifically developed for the simulation of digital systems. In summary, the design of digital systems and computers can be made more meaningful through the aid of such digital simulation programs.