Engineering Commons^™

The Design Criteria Of A Phoswich Transducer., Richard L. Crawford

Electrical and Computer Engineering ETDs

This dissertation is an experimental and theoretical treatise on the design criteria of a phoswich transducer. The major emphasis is on the application in a gamma-ray spectrometer. The conversion efficiency, gamma-ray cross sections, response to charged particles, luminescence decay time, spectral response and physical qualities are discussed, in considerable detail, in making the optimum choices for the inorganic crystal and the organic phosphor which will act as the charged particle anticoincident shield. The effect of the thickness of the anticoincident shield on resolution, the percentage of gamma-rays absorbed, the percentage of gamma-rays that are atten­uated in energy and the lower …

Electric Fields From Airborne Vertical And Horizontal Dipoles At Very-Low Frequencies, A. H. Garry Gibson

Electrical and Computer Engineering ETDs

A gap exists in present-day knowledge of the electric fields in the earth which are radiated from elevated antenna structures in the earth-air-ionosphere waveguide. It is the purpose of this paper to present a method of estimating the electric field at the earth-air boundary, caused by elevated antenna structures, and to show the existence of new phenomena that may lead to an improved design of communication systems.

Radiation Characteristics Of A U-Slot Antenna., Richard Paul Brueggemann

Masters Theses

"The radiation equations for a simple rectangular slot antenna are derived as a function of the field distribution in the slot. The electric field distribution in the slot is then formulated as a function of the aperture dimensions. The U-shaped slot antenna is described as an extension of the rectangular slot theory and the actual field is measured in the slot for comparison.

The far field equations a.re derived for the U-slot antenna similar to those for the rectangular slot antenna and are evaluated using the formulated distributions in the slot for antennas of two different electrical sizes. The equations …

Synthesis Of Unity-Gain Rc Networks From Second Degree Transfer Functions., Ronald L. Mcnally

Masters Theses

"A synthesis procedure is presented which realizes second order open circuit transfer functions. This procedure is developed using parallel networks. The transfer functions for each parallel network are obtained by use of separation parameters. Two constraints are used in the development: first, the realized network must be an RC network; second, the desired multiplicative gain constant must be realized. With these constaints a parameter space is developed which aids in the selection of the proper parallel networks to be combined. Necessary and sufficient conditions are developed which are used to test the transfer functions. The realization simply consists of the …

An Investigation Of The Adaptability Of The Linvill Model For Transistor Synthesis, John A. Reagan

Masters Theses

"The Linvill transistor model may be used for transistor synthesis if the model accurately approximates transistor response and may be readily simulated on an analog computer. Experiments were performed on a transistor to determine the Linvill model parameters. The transistor's large-signal transient response was investigated by pulsing the emitter with a current that drove the transistor from the active region of operation into saturation. The same problem solved experimentally was then solved analytically by replacing the transistor with the Linvill model. The experiment was then simulated on an analog computer by using the equations that govern the Linvill model's response. …

On Optimum Receiver Using Decision Theory, Philip T. Tai

Masters Theses

“In recent years communication engineers have given increased attention to the study of communication through random media. The name random is used to describe a medium the properties of which are stated only in a statistical sense. For example the impulsive response of a certain medium may only be known as one of an ensemble of possible impulsive responses; the particular member of interest being drawn up according to some statistical rule. In other words there exists some "uncertainty" concerning the characteristic description of the medium. Significant work on these problems has been done by Price and Turin. Related work …

An Analysis Of The Simulated Inductande Obtained From Forward Biased Semiconductor Diodes., Everett Harold Vannoy

Masters Theses

"The problem undertaken in this thesis is to study the simulated inductance observed in forward-biased abrupt junction p-n diodes with a highly doped p region and a nearly intrinsic n region and show that it is due to conductivity modulation. Unlike other analyses of this phenomenon, a voltage step is applied to the diode in such a direction as to forward bias it and the behavior of the injected minority carriers are observed. By comparing the resultant current through the diode to the relationship predicted by the equivalent circuit of the diode, an expression is obtained for the simulated inductance. …

The Resolution Of Two Known Signals In White Gaussian Noise., Peter Cheng-Fang Wang

Masters Theses

"The problem of resolving two signals F1(t) and F2(t) in white Gaussian noise n(t) is treated here as a problem in statistical decision theory. We assume a situation in which one of two similar signals is present and an observer is asked to make a decision concerning which of the signals is present with a tolerable probability of error. The observer is allowed to use the best system which he can design for this particular purpose. Of course, this observation will be disturbed by noise and therefore, the observer is led to ambiguous selections. It is apparent that the optimum …

Optimum Zero-Memory Nonlinear Filter, Benjamin Shaw-Hu Wang

Masters Theses

“The purpose of this report is to review the basic work described by Zadeh insofar as systems of class N₁ are concerned and to apply his general results to a specific problem in which a non-linear filter is mandatory simply because the linear filter is essentially ineffective. The ineffectiveness stems from the fact that the autocorrelation function of the signal plus the noise has essentially the same variational character as the signal alone. Therefore, the transfer function of the linear filter turns out to be simply a constant. Thus, the output of the linear filter is just an attenuated …

Time Optimum Switching Zones In Multiple-Valued Control Systems, Jack Leroy Crawford

Masters Theses

"Present control system theory provides the criteria necessary to bring a second-order single-valued system to rest in a minimum time after a step input. The bang-bang type controller has been developed to obtain this optimum response.

However, existing theory fails to provide the necessary information to obtain the optimum response from a second-order rotational system when multiple values of angular position are allowed. This thesis extends the control theory to include these multiple-valued systems by showing the existence of what are called optimum switching zones. These zones predict which of the infinite number of switching curves in a multiple-valued system …

Compensator Design For Unity Feedback Systems Using An Analytical Method, Chang-Yu Wu

Masters Theses

“In control systems engineering it is frequently necessary to compensate a fixed plant whose transfer function cannot be changed. Usually the characteristics of the resulting system are established in terms of steady-state and transient performance specifications. Generally it is necessary to insert a compensator which insures stability as well as satisfies the specifications.

In this thesis an analytical method is developed to determine the transfer function of the compensator in order to satisfy the following set of specifications. The fixed system is assumed to contain one non-linearity, saturation. The input to the saturable device is constrained in a statistical …

High Order Bang Bang Control System., Shing-Chou Pi

Masters Theses

"The problem undertaken in this thesis is to find a representation of a nonlinear controller to minimize the response time of a limited input plant whose transfer function has N negative real poles. The extension of the phase-space method to automatic control systems described by high-order differential equations with a general high-order input is considered.

The design utilizes a maximum effort controller whose switching time is determined by the concept of switching hypersurfaces of the system in N-dimensional phase space and the concept of a distance function, which is & geometric length between the initial state point and the switching …

Artifact Filter., Kent William Swearingen

Masters Theses

"Peripheral blood pulse monitors are highly susceptible to noise-artifact-- in their present stage of development. The purpose of this thesis is to demonstrate a feasible means for filtering the artifact, using existing monitors. Since no peripheral pulse monitor (transducer) was available for experimentation, a simulated test input was devised with frequency variations from JO cycles/minute to 1.50 cycles/minute.

The filtering circuit predicts the time location of each input pulse. The location of the prediction is governed by the accuracy of the preceding prediction. This is controlled by an R-C timing circuit with a Schmitt Trigger and relay.

From the data …

Optimalization By Peak-Holding, Curtis W. Dodd

Masters Theses

"The problem presented is a study of the peak-holding method of optimalization. This method applies to a system that has an extremum.

After describing how the complete system, consisting of the controller and the controlled system, works; variations in the controller are presented. These variations are changes in the final stage of the controller, the servo. A phase-plane analysis shows how the output of the controlled system varies with its rate of change. Limitations are presented which tell why the system cannot be kept at its peak value at all times. Finally an analog simulation is used to study the …

Real Time Testing With A Time Scaled Analog Computer., Wayne F. Balsman

Masters Theses

"A present limitation to the testing of a physical subsystem within an analog simulation is that the analog computer must compute in real time. If it is necessary to time scale the simulation of the complete system, a physical subsystem of the complete subsystem may not be tested within the simulation. Therefore, a means of changing the time scale of the analog signal is needed to test a physical subsystem within a time scaled analog computer simulation.

In this thesis a means of time conversion by sampling the analog signal at one rate, storing the samples, and reading the samples …

A Study Of Certain Atmospheric Effects On Radar Accuracy, Kenneth R. Swimm

Electrical and Computer Engineering ETDs

Along with other factors, accurate radar target location is dependent upon a knowledge of the electromagnetic propagation path. The propagation path is a function of the characteristics of the medium through which the signal travels. Advances in the resolution capabilities of modern electronic tracking equipment have led to requirements for more accurate prediction of atmospheric refraction characteristics. The inherent error of the equipment is, in many cases, less than the error introduced by the atmospheric refractive effects. After corrections to observed launch angle and target range have been made on the basis of atmospheric refraction information, residual errors in range …

The Magnetocardiogram A New Approach To The Fields Surrounding The Heart, R. A. Stratbucker, C. M. Hyde, S. E. Wixon

Department of Electrical and Computer Engineering: Faculty Publications

Experiments have been conducted which reveal the existence of a detectable magnetic field associated with cardiac electrical activity. The relationship between the magnetic record and the electrocardiogram has been explored and it is shown that under certain conditions of axis orientation the voltage induced into a toroidal sensing element around the heart has the form of the first time derivative of the electrocardiogram. A formula based on Maxwell's equations has been developed to relate these two phenomona.

A Five Dimensional Field Theory., Scott Holzhauser

Electrical and Computer Engineering ETDs

Several authors in the past have utilized the five dimensional manifold to accomplish their ends, as the next few sections explain. The ends are frequently different, however, Corben1,2 relates his fifth dimensional variables to rest quantities, such as the "rest mass density" and "rest charge density." Flint3,4,5 uses x as an unobservable 5 cyclic coordinate, and Ingraham6 interprets x as a "parameter of finiteness" that keeps finite the usual field quantities.

An Acoustic Antenna With A Hollow Searchlight Pattern, Thurlow W.H. Caffey

Electrical and Computer Engineering ETDs

Economy, repeatibility, and convenience make it desirable to model a radar system by means of an acoustic system. The modeling is based upon the fact that, in a lossless medium, both EM-waves and acoustic waves obey a traveling wave equation of the same form. Furthermore, the field components of a plane wave in each system are related to each other by equations of the same form.

Adaptive Communication Systems, Arthur M. Breipohl

Electrical and Computer Engineering ETDs

The purpose of this study is to investigate an "adaptive" communication system in order to characterize the elements of adaptation. Although the term "adaptive" does not have a universally accepted meaning in the technical literature, it is usually applied to systems that have a significant ability to adjust their performance automatically over relatively wide variations in environment. In this sense almost any feedback system is adaptive, but the term is usually reserved for the more exotic systems which appear to make a deliberate effort to monitor the environment and then adjust their performance. Man is usually taken as the primary …

Computation Of The Dipole Moment Of A Coaxial Antenna In Sea Water., Richard B. Reinman

Electrical and Computer Engineering ETDs

The purpose of this paper is to develop a meaningful expression for the dipole moment in dissipative medium. Since the dipole moment is dependent on the current distribution which in turn is a function of system parameters, and might well start with determination of the input impedance. Two of the most popular methods for determining input impedance to a radiator in an air medium are 1) the induced emf method, and 2) a method whereby the power flow across a spherical surface is calculated as the radius of the sphere becomes infinite. Both methods assume a current distribution; only the …

Wave Propagation Past A Change In Cross-Section, Samuel A. Cone

Electrical and Computer Engineering ETDs

This thesis was undertaken to accomplish the following:

1) To experimentally determine the longitudinal strain distribution in the region of a change in cross-section of a cylindrical bar when a longitudinal wave passes this region.

2) To experimentally determine the longitudinal strain distribution in the incident, reflected and transmitted waves produced by a longitudinal wave in the region of a change in cross-section of a cylindrical bar.

3) To experimentally observe, at a distance of several bar diameters away from the change in cross section, the relation between the magnitudes of an incident longitudinal wave and the reflected and transmitted …

Fortran For The Maniac, Richard C. Lindberg

Electrical and Computer Engineering ETDs

It is not the intent of this thesis to present the rules of FORTRAN; it is assumed that the reader is generally familiar with the principles of FORTRAN programming. Rather, this is an attempt to describe FORTRAN in relation to the compiler program it actually is -- a machine language program which translates FORTRAN statements to machine language instructions, the latter capable of being executed by the same computer. The FORTRAN statements will be interpreted in terms of the compiler program which performs the translation, and algorithms for these statements will be described.

Programming Manual For The Maniac Assembly Routine, Robert C. Ashley

Electrical and Computer Engineering ETDs

No abstract provided.

An Investigation Of Methods For Analyzing Networks Containing One Nonlinear Element, Dustin J. Wilson

Electrical and Computer Engineering ETDs

The inclusion of a single nonlinear element in a general N-loop network greatly complicates the resulting equations and prohibits a straightforward solution. The object of this investigation is to provide a method for solving such networks. In particular, a reduction of the network coefficient matrix will be considered in order to obtain one nonlinear equation and (N-1) linear equations. It will be shown that the form of the nonlinear equations is always the same, and a procedure for approximating the solution of equations of this type will be given.

Transistorized Circuits For Telemetry, Dominick Misciascio Jr.

Physics & Astronomy ETDs

This thesis is concerned with the telemetry of small DC signals from photomultiplier tubes. The circuitry must have a high input impedance so as not to load down the photomultiplier tube and a low output impedance which is capable of controlling the current through a small incandescent bulb. This bulb is used to illuminate a photoresistor. The output of the circuit consists of a variation of the resistance of the photoresistor. This variable resistance is conventionally converted into a variable audio frequency which is transmitted to the receiving station on a radio-frequency carrier. The output resistance must be independent of …

A Unique Analog-To-Digital Voltage Conversion Network, Thomas O. Summers

Electrical and Computer Engineering ETDs

The increasing utilization of digital data acquisition systems has resulted in the design and development of a large number of different analog-to-digital voltage converters. Each of these designs exhibits varying specifications with regard to accuracy, speed, environmental tolerance, reliability, and cost.

These specifications are usually interrelated and the nature of the interrelations are, in turn, related to the design approach.

As an example of these interrelations, one could consider the specifications of a converter designed around an electro-optical approach requiring a cathode ray tube with coding mask. In this approach, the analog input voltage causes the deflection of a swept …

Measurement Of Thin Film Thickness By The Crystal Resonance Method, David G. Adams

Electrical and Computer Engineering ETDs

Recent years have seen a tremendous increase in thin film activity. The electronics industry, in particular, has become increasingly active in the development and production of thin film components and complete micro-electronic circuits laid down as thin films. The principal methods of producing thin films are by chemical and electrolytic processes, and by evaporation and sputtering in vacuum. One of the problems associated with film deposition in vacuum involves the measurement of film thickness, a difficult task because: 1) the thicknesses encountered are typically measured in hundreds of angstroms; 2) the films are not physically flat; and 3) they do …

Properties Of Radar Augmentation For Missile Targets., Warren T. Randall

Electrical and Computer Engineering ETDs

This thesis presents a study made to investigate problems involved in the design of certain radar augmentation devices. The task arose from the requirement to add realistic simulation of radar reflection characteristics to drone targets during an evaluation of the performance capability of the Falcon missile, conducted by Hughes Aircraft Company at Holloman Air Force Base, New Mexico. In addition to performing a mathematical analysis of the problem, the author who asked to design and build equipment which would present a visual demonstration of the reflection activities. The necessary definition of radar properties and a description of the test equipment …

A Time Optimum Bang Bang Control System Under Specified Inputs., John F. Curtin

Masters Theses

"The problem presented is a study, by simulation on an analog computer, of a time optimum "bang bang" control system with a second order plant. Phase plane analysis techniques are used to describe the performance of the second order plant under the action of a maximum effort controller. From this, the system logic is developed for time optimum response to a step reference input. A fast time model of the plant is used to obtain repeated high-speed extrapolations of the plant outputs, at the same time a linear predictor generates future values of the reference. The error functions thus found …