Engineering Commons^™

Pulse Width Modulated Adaptive Delta Modem Design And Analysis, Gregory L. Milne

Retrospective Theses and Dissertations

A unique design of a voiceband adaptive delta modem will be presented. The modulator utilizes a constant amplitude variable width pulse combined with the principles of delta modulation. This results in a modem that has lower amplitude distortion, requires less transmission channel bandwidth, and is less prone to slope overload than conventional adaptive delta modems. The design also allows the use of a simple single integration demodulator while maintaining fidelity.

The modem design and analysis is presented assuming a transmission channel which is bandwidth limited and amplitude limited.

Apodization Of Surface Acoustic Wave Three Phase Unidirectional Transducers, Benjamin P. Abbott

Retrospective Theses and Dissertations

This thesis presents an introduction to surface acoustic wave (SAW unidirectional transducer (UDT) apodization. An unbalanced apodization structure is described. The structure is shown to suffer from an unbalanced capacitive effects, significant apodization losses and passband ripple. A balanced UDT structure is developed for the purpose of improving performance and minimizing undesirable effects associated with the unbalanced structure.

Each apodization structure is analyzed and compared using a typical impulse response of a SAW transducer. The analysis is accomplished using SAWCAD2, a unidirectional Surface Acoustic Wave Computer Aided Design FORTRAN-77 program developed at the University of Central Florida. Having shown the …

A Zero Extraction And Separation Technique For Surface Acoustic Wave And Digital Signal Processing Fir Filter Implementation, Keith V. Lindsay

Retrospective Theses and Dissertations

Presented is a new method of separating the zeros of a Finite Impulse Response (FIR) filter producing optimal digital filter of surface acoustic wave (SAW) design implementation. Overviews of zero extraction algorithms and of FIR filter design using the Remez Exchange algorithm are presented (McClellen et al. 1973).

The computer aided design (CAD) procedure presented allows the designer to specify the general filter characteristic which the Remez algorithm translates to FIR time domain coefficients. These coefficients are readily translated to the frequency (z) domain, producing an Nth order polynomial in z. The characteristic polynomial is factored to determine all roots …

A Colpitts Oscillator Design Technique Using S-Parameters, Timothy K. Johnson

Retrospective Theses and Dissertations

This research report describes a method for designing a Colpitts oscillator using S-parameters. The oscillator components are grouped into three functional blocks: 1) an unstable active network (which includes the transistor, feedback capacitor, and input resistor); 2) an output matching network (which includes the inductor, tuning capacitor, and load); and, 3) an input matching network (which consists of the remaining tank capacitor). This configuration not only satisfies the standard Colpitts oscillator topology, but allows the use of three simple criteria (based on the network S-parameters) to predict oscillation. A computer program was developed to calculate specific tank component values based …

Electromagnetic Scattering From Stacked Gratings, Pok K. Kwan

Retrospective Theses and Dissertations

The theory of scattering matrices and microwave network analysis are employed to solve the problem of scattering from cascaded infinite periodic gratings. The total reflection and transmission coefficients are calculated as functions of angle of incidence, wire spacing for each grating, grating separation, wire thickness, and number of gratings that comprise the cascaded structure. Moreover, the problem of stacking dielectric slabs with periodic gratings is formulated and solved. In all cases, the Secant Corrector Spectral Iteration approach is used as a numerical method for calculating the desired currents and fields.

Finally, calculated values of the reflection and transmission coefficients are …

Switched-Capacitor Programmable Sallen And Key Lowpass Filters, Karl P. Eriksson

Retrospective Theses and Dissertations

This thesis deals with a different approach to switched-capacitor filters than previously seen by the use of a Sallen and Key topology. It is shown that a Sallen and Key second-order topology approach to a switched-capacitor filter gives reasonable filter performance results, contrary to what the literature leads one to expect. It is also shown that the Sallen and Key second-order topology with modification to a third-order section with buffers results in a high performance switched-capacitor filter with fewer components than previous switched-capacitor filters. This results in fewer monolithic chip size requirements, reduced power requirements, and less cost. Higher order …

A Peripheral Subsystem Optimized For Computer Image Generation Applications, John J. Bloomer

Retrospective Theses and Dissertations

Requirements for ever increasing realism in real time computer image generation for military mission and commercial training, have generated the need for a higher performance, more cost effective front-end processor. Current computer image generators front-end general purpose computers are reaching their performance limits in current architectures.

The tasks of this processor include: realtime computations, magnetic disk control, data transfer and direct memory access to and from the balance of the image generator. A new front-end processor system is under development. This multiple-bus, multiprocessor architecture in and of itself does not address disk and external data transfer. A peripheral subsystem is …

The Effects Of Trace Organic Carbon On Aluminum Solubility, Fernand J. Tiblier

Retrospective Theses and Dissertations

Alum jar tests were performed on raw portable waters of varying TOC. Parameters monitored include alum dose, pH and mixing conditions. Finished waters were analyzed for residual aluminum, residual TOC and hardness in order to investigate the effects of TOC on aluminum residual as would be encountered by alum coagulation and lime softening process in practice.

Three-dimensional graphs of residual aluminum, residual TOC and pH were constructed to illustrate the relationship among these measured parameters for the different sources. Statistical analyses were conducted to verify aluminum-organic complexation at reduced alum dosages for varying TOCs; initial TOC, reaction pH and dose …

Development And Testing Of A Heuristic Line Balancing Program For A Microcomputer, Dean B. Creech

Retrospective Theses and Dissertations

Development, operation, and testing of a heuristic line balancing program for a microcomputer are discussed. Tasks are grouped into work stations along an assembly line such that the number of work stations required is minimized.

The model is built primarily using the Hoffman (1963) procedure with modifications described by Gehrlein and Patterson (1975). For purposes of comparison the Rank Positional Weight technique (Helgeson and Birnie, 1961) is also included in the model.

Testing included thirty-seven different balances using problems from the literature. For each balance, both Rank Positional Weight and Hoffmann solutions were obtained in the forward and reverse directions. …

The Effect Of Thickness On Neuber's Rule For Estimation Of Fatigue Life, Shahram Elmi

Retrospective Theses and Dissertations

To predict the fatigue life of a notched member from a strain-life curve, the high strain concentration at the root of the notch must be known. For determining this high (post yield) strain, the Neuber’s Rule (for plane stress) and linear rule (for plane strain) can be applied. To investigate the accuracy of these method a notched member which is subjected to fully reversed cyclic loading is analyzed by the finite element method. Moreover, members with different thicknesses are analyzed with three dimensional elements, and a correlation between plane and three dimensional data is obtained. This correlation may be used …

A Theoretical Evaluation Of Water Surface Changes In A Circular Reservoir, Hossein G. Tehrani

Retrospective Theses and Dissertations

The purpose of this project is primarily to develop an equation to estimate the time that it will take for the water surface to decrease to another depth in an inverted conical-shaped reservoir behind an earth dam by means of the falling head permeability concept. This equation can be applied to the earth embankment either with or without underdrain. Since the derived equation for time span is a complicated and tedious matter, a computer program has been developed for solving this equation.

The computer program is written in BASIC language and executed on a Tektronix 4051 microcomputer. Primary effort has …

Automated Q-Factor Measurement Via A Network Analyzer, Fadi E. Ayoub

Retrospective Theses and Dissertations

An algorithm is developed for the HP automated network analyzer that can determine the three basic parameters of microwave cavity resonators: the unloaded resonant frequency fo, the unloaded Q-factor Q_o, and the coupling coefficient β. The input reflection coefficient of the resonator is measured via the network analyzer, which is driven by an HP desk computer. The graphical techniques (Smith Chart) are replaced by the much faster calculations on the computer using numerical techniques. Stirling and Bessel’s formulas, in conjunction with the central difference interpolation method, are used to interpolate between sampled points to enhance the accuracy …

High Speed Latchup-Free Cmos Using Tisi2, N-Well, Technology, Faheem Mohamedi

Retrospective Theses and Dissertations

This report discusses high speed latchup-free 0.5 µ m-channel CMOS using self-aligned TiSi₂ and deep-trench isolation n-well technology. This technology of deep-trench isolation combined with the epitaxial layer eliminates many problems such as poor device to device isolation, latchup susceptibility and relatively high sheet resistance of n+ and p+ diffusion layers. Thus CMOS devices operate at a propagation delay time of 140 p with a power dissipation of 1.5mW per inverter and attain a maximum clock frequency of 700 MHZ without suffering from latchup even at a latchup trigger current of 100 mA.

Ground Penetrating Radar In The Detection Of Subsurface Cavities Related To Sinkhole Activity In Florida, Marianne Sweeney

Retrospective Theses and Dissertations

The Florida peninsula is underlain by limestone undergoing continuous solution process resulting in subsurface cavity formation. Increased land development has led to costly structural damage and water supply contamination due to surface subsidence and collapse in areas overlying such cavities. Conventional drilling methods cannot guarantee detection of isolated cavities. A geophysical technique known as ground penetrating radar (GPR) is a non-destructive method in geotechnical investigation capable of surveying large areas quickly and efficiently. GPR works as an echo sounder with a continuous similar graphic display. Cavities are identified by hyperbolic patterns caused by reflections from variations in electrical properties of …