Electrical and Computer Engineering Commons^™

Circuit Analysis Of A Gas Flow Switch, Teri Marie Owens

Electrical & Computer Engineering Theses & Dissertations

The circuit analysis of a gas flow switch is presented. The objective of the analysis is to model the switching process during spark gap breakdown. This information is useful in understanding switch operation and identifying ways to improve switch performance.

A lumped circuit model is used to describe a gas flow switch during the switching process. Certain circuit element values are determined experimentally through static tests. Other component values, including a time-varying switch resistance and inductance, are estimated from current measurements. In particular, unknown constants in expressions for gap resistance and inductance are determined using an iterative parameter estimation technique. …

Experiments Conducted On The Electron Beam Produced By A Dense Plasma Focus, Mark Steven Pronko

Electrical & Computer Engineering Theses & Dissertations

An experimental investigation was conducted using a 34-kJ Dense Plasma Focus (DPF) in which the possible enhancement of the electron beam was addressed. Electron beams ejected from the DPF have been observed to exceed 30 kA with pulse durations of a few nanoseconds. Enhancement was considered to be either an increase in the probability that the peak beam current exceeded some lower limit, or an increase in the mean energy of the beam electrons. The investigation was divided into two parts, each addressing one of the aspects of enhancement.

In the first part of the investigation, an axial magnetic field …

An Investigation To Model Radar Backscatter From Ridged First Year Sea Ice, Betty Lou W. Jackson

Electrical & Computer Engineering Theses & Dissertations

This thesis investigates the response of a radar type sensor, the microwave scatterometer, to meter scale roughness of first-year sea ice. The scatterometer measures the absolute backscattered power from a target, and use of the radar equation permits calculation of the surface reflectivity expressed as the radar scattering coefficient, σ⁰ also called the normalized radar cross section. This thesis develops an empirical, one dimensional model to predict the backscattered power from ridged first-year sea ice of known surface topography, by interpreting the surface as a series of angular facets and summing the proportional power from each facet. The model …

A Pattern Analysis Algorithm For Wind Ambiguity Removal, Jaime R. Tormos

Electrical & Computer Engineering Theses & Dissertations

Some remote sensing devices, such as satellite microwave scatterometers, produce sampled wind vectors that are accurate in speed and streamline direction, but have a directional ambiguity of 180°. The extraction of information from the two dimensional wind vectors is readily handled using pattern analysis techniques. It is shown that there is sufficient information in the spatial relationships of the generated windstream vectors to recognize the driving meteorological wind patterns. This then leads to the resolution of the wind ambiguity problem. This thesis presents the development of a pattern analysis algorithm that generates a measure of the raw data set that …

A Method Of Modeling Multirate Two-Dimensional Recursive Digital Filters Author, Albert P. Gerheim

Electrical & Computer Engineering Theses & Dissertations

This dissertation presents a method of modeling two dimensional sampled data systems with two sampling rates in each dimension. This methodology is applied to the problem of synthesizing two dimensional velocity filters using one dimensional prototypes and multirate concepts.

The modeling method includes the replacement of scalar z-transforms of signals by vectors of polynomials, and the replacement of scalar z-transforms of impulse responses by matrices of polynomials.

The synthesis of velocity filters is accomplished through the use of coordinate transformations in the z-transform domain which skew the ω₁ -ω₂ axes on the unit bidisc. The filters synthesized using …

Eigensystem Assignment Using Singular Value Decomposition, Ronald Dean Alley

Electrical & Computer Engineering Theses & Dissertations

An interactive approach to computer-based control system design is formulated and presented. There are four key features to this approach. Singular value decomposition is used for several matrix operations, rather than Gaussian methods, for improved numerical accuracy. Dynamic memory allocation is implemented to reduce system core requirements for matrix storage. Interactive plant parameter modification is implemented to allow user interaction with the program~ reducing design time. Finally, disk input-output is minimized to increase response time.

This design system is demonstrated in examples in which distinct user specified eigenvalues are achieved, and eigenvectors close to a user specified set of eigenvectors~ …

The Development Of A Stepped Frequency Microwave Radiometer And Its Application To Remote Sensing Of The Earth, Richard Forrest Harrington

Electrical & Computer Engineering Theses & Dissertations

The design, development, application, and capabilities of a variable frequency microwave radiometer are described. This radiometer has demonstrated the versatility, accuracy, and stability required to provide contributions to the geophysical understanding of ocean and ice processes. The design technique utilized a closed-loop feedback method, whereby noise pulses were added to the received electromagnetic radiation to achieve a null balance in a Dicke switched radiometer. Stability was achieved through the use of a constant temperature enclosure around the low loss microwave front end. The Dicke reference temperature was maintained to an absolute accuracy of 0.1 K using a closed-loop proportional temperature …

Precise Frequency Control Of The Voltage Controlled Oscillator Using Finite Digital Word Lengths, Timothy Peter Hulick

Electrical & Computer Engineering Theses & Dissertations

For an oscillator that is periodically swept in frequency between some upper and lower bound, the output amplitude may easily be made constant and therefore known with a high degree of certainty. The instantaneous frequency exists only at a point in time and therefore possesses a zero probability of existing at any point. This thesis deals with the development of a method for interchanging the probability density functions of amplitude and frequency so that the latter becomes known with certainty while the former is known only to the extent that it is within a certain range.

The method developed makes …

An Efficient Dft Algorithm Using The Walsh Transform, Albert P. Gerheim

Electrical & Computer Engineering Theses & Dissertations

The matrix transformation relating the sequency and frequency domains is derived. It is shown that these­ frequency-to-frequency conversion can be performed via a computationally efficient sparse matrix algorithm. The sequency-to-frequency algorithm can be used with a fast Hadamard transform to implement a discrete Fourier trans­ form. The efficiencies of this combined algorithm and a radix-two fast Fourier transform are compared.

The algorithm is applied to the sequency domain de­ sign of a Wiener digital filter. Improved computational efficiencies are achieved relative to the procedure de­veloped by Kahveci and Hall (9).

Simulation And Analysis Of A Second-Order System With An Added Finite Pole And/Or Zero, William Robert Bodwell

Electrical & Computer Engineering Theses & Dissertations

An original system whose transfer functions consist of two infinite zeros and two finite poles is modified by the addition of a finite pole and/or finite zero. Statespace techniques are used to obtain equations for simulating the transfer functions on both analog and digital computers. Sample cases were selected and simulated to demonstrate the various types of responses. Analysis of the computer results and mathematical analysis of the transfer functions provide nomographs for estimating the response of the systems to a step-input and methods for obtaining equivalent pole/zero configurations.

A Study Of Thin-Film Superconducting Junctions, William P. Korink

Electrical & Computer Engineering Theses & Dissertations

The information presented in this paper is the result of research conducted toward the development. of a reproducible thin-film superconducting junction. The results of this experimentation and the equipment and procedures used are provided.

A qualitative explanation is given for the theory used in the derivation of the volt-ampere characteristics of thin-film superconducting junctions of metal-insulator- metal construction. This explanation entails the electron flow through the insulating layer through the use of the Fermi-Dirac and density of states functions.

The theoretical investigation is based on the BCS Theory and results in volt-ampere characteristics that agree very well with published experimental …