Engineering Commons^™

Performance Of Second Order Delta Modulation System, Reza Aghazadeh Alavi

Theses

The performance of an ordinary delta modulation (DM) system under three types of input signals was investigated. These signals were band limited Gaussian noise, 800 Hz sine wave, and speech signal. The affects of 2nd DM added to the ordinary DM in improving the performance of the system were researched. This is called a Second Order Delta Modulation System. The obtained data showed an increase of about 3dB in the overall Signal to Noise Ratio (SNR) of the system, in the worse case.

Input to the 2nd DM is the band limited error of the first DM. A linear phase …

The Design And Fabrication Of Dielectric Waveguides For Use With High Power Carbon Dioxide Lasers At 10.6 Microns, Jong Min Kim

Theses

The feasibility of constructing a feasible transission system to propagate 10.6 microns energy from a CO₂ laser is explored. The system is to be used in a clinical surgical setting to deliver as much as 100 watts of CW power from a surgical CO₂. laser to a surgical target.

The optimal transmission system is a slender flexible cylindrical structure, 1 mm in diameter and 1.5 m long. The structure should be sufficiently flexible to be bent into a 5 to 10 cm radius without a significant increase in the attenuation constant. For clinical applications the system must …

Modeling And Simulation Studies On Nmos Vlsi, Chang-Joo Kim

Theses

This thesis has two parts. The first part deals with the theoretical analysis and experimental verification of the variation of channel resistance and threshold voltage as a function of drain and source voltages in NMOS transistor with the substrate taken as reference. And the second part deals with simulation and optimization of the NMOS sense amplifier circuits.

Firstly, the NMOS transistor with the substrate taken as reference node is analysed and a set of formulas is derived for the variation of channel resistance as a function of the terminal voltages. Experimental results (using SCL 4007AE from Signetics) show good agreement …

Digital Signal Processing Implementing The C Language With Graphics Spectrum Analysis Display, Anuraksa Mahanirananda

Theses

Digital Signal Processing discussed in this thesis is concerned with the transformation of signals or complex wave forms From time domain to frequency domain and vise-versa, implemented on microcomputer systems. The primary principles are: speed of transformation, ease of usage as an application program, capabilities of graphics displaying transformed data (such as power spectrum analysis), storing these data onto record files, and capability of using these data Files and programs with other application programs.

We begin by discussing briefly, the concepts of Fourier theory, Discrete and Fast Fourier Transform, algorithms of Fast Fourier Transform and bit-reversal. Then we implement these …

Microcomputer-Based Automated Feeding And Monitoring System For Eating Behavior Studies On Rats, Tseng-Huang Shih

Theses

An instrumentation system has been designed to monitor feeding behavioral experiments on rats. This instrumentation system is capable of performing these experiments in an automated manner without any human intervention. It is capable of monitoring these experiments concurrently in six cages. It exhibits several features that make it more versatile than previous feeding & monitoring systems. It is also capable of storing the data generated on to a floppy disk and later printing out the data for analysis.

Another feature that makes it more versatile is the flexibility of the system. Construction of a parameter file before doing the experiment …

The Design Of A Resonant Post Waveguide Filter, Ramjee Prasad

Tanzania Journal of Engineering and Technology (TJET)

A seven stage, quarter-wave coupled, single post, resonant cavity type waveguide filter has been studied. The posts are placed according to the Tchebyscheff distribution. The filter is designed and fabricated to meet the following specifications: Centre frequency: 9.31 GHz, Number of stages = 7, 3-dB bandwidth = 300 Mhz, Ripple tolerance in the passband = 0.5 dB. The frequency behaviour of this filter has been experimentally studied and is in close agreement with the specifications.

Gain Margin And Phase Margin Interrelationships, M Luhanga

Tanzania Journal of Engineering and Technology (TJET)

The gain margin and the phase margin Of a control SY Stem are important parameters in the determination of the relative stability of control system. In this paper We derive general interrelationships between these parameters.

Polarizing Beam Splitters For Infrared And Millimeter Waves Using Single-Layer-Coated Dielectric Slab Or Unbacked Films, R. M.A. Azzam

Electrical Engineering Faculty Publications

No abstract provided.

Response Of The Rotating-Detector Ellipsometer To Incident Partially Polarized Light, R. M.A. Azzam

Electrical Engineering Faculty Publications

No abstract provided.

Thin-Film Beam Splitter That Reflects Light As A Half-Wave Retarder And Transmits It Without Change Of Polarization: Application To A Michelson Interferometer, R. M.A. Azzam

Electrical Engineering Faculty Publications

The refractive index n₁ of a transparent layer of quarter-wave optical thickness coating a transparent substrate of refractive index n₂ can be chosen to produce half-wave retardation (HWR) in reflection and no change of polarization in refraction at any angle of incidence ø. The function n₁(ø, n₂), and the associated polarization-independent reflectance of the film-substrate system R(ø, n₂) are determined. Such a coated surface can be used as a beam splitter with excellent characteristics (e.g., split fractions that do not depend on source polarization, a split beam whose polarization is identical …

An Investigation Of Overvoltage Effects On A Gas-Blown Spark Gap, Michael Steven Mazzola

Electrical & Computer Engineering Theses & Dissertations

This experimental investigation addresses the anomalous overvoltage breakdown and subsequent recovery characteristics observed in gas-blown spark gaps. Previous investigations have reported a two-stage recovery process in self-break, pulse-charged, gas-blown spark gape in which the spark gap recovers first to an intermediate breakdown strength before recovering to the undisturbed breakdown voltage. The recovery process has been explained in terms of two different characteristic times. The first is that required to obtain initial recovery in which the spark gap regains its intrinsic breakdown strength. The second time is that required to obtain final recovery in which the pulse-charged spark gap regains the …

Multi-H Continuous Phase Modulation : Its Properties And Analysis, Jyung-Cheng Chen

Theses

Multi-h CPM, a generalization of CPFSK and also one of the so-called Combined Modulation and Coding schemes, is useful in digital communication systems where both the bandwidth and power are constrained. The increased signal processing complexity, which can be viewed as the third communication resource, is used to trade for both power and bandwidth, and to approach the error-free communication promised by Shannon's theorem.

The transmitted multi-h CPM signal carries a coded sequence of continuous phase changes; the possible phase states form a cylindrical trellis in phase and time, in which the modulation indices are reused in a cyclical fashion. …

Logic Simulation And Methodologies For Design For Testability, Ravi Shankar Prasad Mallampalli

Theses

This thesis describes the method used for developing the standard TTL blocks using the logic simulator SPLICE1. It also gives a comprehensive overview of methods which can be used for designing a circuit which is testable. A format called Electronic Design Interchange Format (EDIF) is also described as a tool which can be used for transporting design data in the VLSI indgstry.

Gallium Film Formation By Ion Cluster Beam Deposition, Te-Chuan Hsu

Theses

Gallium thin films were deposited by Ion Cluster Beam (ICB) from pure gallium. This research had two objectives: to develop a practical method of crucible heating to generate gallium clusters; and to investigate the influence of ICB system parameters on the formation of clusters and film properties. An electron-bombardment crucible heater with a novel construction was designed. The top section of the carbon crucible was kept at a higher temperature than the middle section to prevent clogging of the nozzle and " spitting " phenomena which were found to occur with the conventional design. Crucible temperatures up to about 1360°C …

Reliability Of Dielectrics : Using Noise As A Diagnostic Tool, Ramesh K. Jain

Theses

The aim of this thesis is to develop a screening method to predict the reliability of a dielectric material. The screen chosen is an electrical noise. The dielectric material studied is varnished fibre glass cloth material supplied by Westinghouse Electric Corporation.

The dielectric material will have varying amount of voids, crystal defects, and surface contaminants impurities introduced during manufacturing process. On application of the electric stress, ionization (corona) will take place. The corona degrades the material due to thermally generated heat, chemical reactions in the voids and ionic bombardment of the material.

An experimental set up is developed to monitor …

The Modeling Of A Self-Oscillating Dc-To-Dc Converter, Frank Andrew Linkowsky

Theses

This thesis develops a model of a nonlinear self oscillating current-or-voltage step-up dc-to-dc converter. Expressions are given that predict the operation of the converter in the time domain and in the state plane. To verify these expressions, a large signal computer simulation technique [1] is used to compare theoretical results with actual measurements. This type of simulation allows a nonlinear switching converter to be modeled with a series of piecewise-linear operating intervals. The resulting waveforms predicted by the developed model show close agreement with waveforms found in the laboratory. Therefore, the model represents a powerful tool that may be used …

Relationship Between The P And S Fresnel Reflection Coefficients Of An Interface Independent Of Angle Of Incidence, R. M.A. Azzam

Electrical Engineering Faculty Publications

The Fresnel reflection coefficients r_p and r_s of p- and s-polarized light at the planar interface between two linear isotropic media are found to be interrelated by (r_s - r_p)/(1 - r_sr_p) = cos 2β, independent of the angle of incidence ø, where tan²β = ∊ and ∊ is the (generally complex) ratio of dielectric constants of the media of refraction and incidence. This complements another relation (found earlier), (r²_s - r_p)/(r_s - r_sr_p) = …

Measurements Of Basic Semiconductor Properties, Abdolreza Ariantaj

Theses

Mobility, resistivity, and total impurity concentration of several purchased p-type silicon samples with known resistivities were measured by Hall effect, experiments utilizing the Van Der Pauw method. The silicon samples will serve as Hall effect standards for future measurements on other semiconductor materials, particularly gallium nitride ion cluster beam (ICB) deposited thin films. The samples which were Freshly etched with hydrofluoric acid had measurement values of 455 cm ² / V.sec, 45.9 Ω cm, and 2.6 X 10¹⁴ cm³ for mobility, resistivity, and total impurity concentration, respectively. The mobility values were within 9.9 per cent, of the published values …

Effect Of Humidity And Moderate Temperature On Microcircuit Failure, Antoine Mikhayel Chaia

Theses

The increased use of microprocessors has brought forth many questions concerning the reliability of these devices.

This research discuss the TTL integrated circuit failure rates, and provides information on the effects of temperature, device complexity and packaging on TTL failure rates under storage condition of 100% R.H. (Relative Humidity) and 100°C and no added humidity at 100°C. Other factors which can affect failure rate are also discussed, including designs, materials process.

Approximately 200 microcircuits of TTL (74LS00) were subjected to extend life testing at 100°C; where 125 chips are tested at 100°C ± 2° and no added humidity and the …

Nervous System Simulation, Jian Chen

Theses

This thesis deals with the nervous system simulation. The Hodgkin-Huxley model and Stein's model are used as basic tools. The author has tried to describe some practical problems by mathematical models.

First, the horse-shoe crab eye is investigated. Light intensity is reported to the brain by the firing frequency of the photoreceptoe. A Poisson process is used to simulate the stimulus to the receptor. The result of the stochastic model coincides with the theoretical one: receptor overlapping decreases the resolving power of the eye; and the lateral inhibition compensates the effect of overlapping.

Second, a nerve muscle model was set …

Realization And Implementation Of A Recursive Digital Convolution Algorithm In Cmos, Lik Tang Cheng

Theses

This thesis describes the implementation of a digital convolver. A recursive digital convolution algorithm was realised and implemented by using CMOS circuitry. This thesis also gives a technical overview of current CMOS processing technologies as well as various novel CMOS logic circuit techniques.

Waveform Analysis Using A Micro Computer, Dakshina K. Murthy

Theses

Harmonic analysis through a micro computer was performed at Brookhaven National laboratory to determine the magnitude and extent of hormonic dIstortionon in their electrical power supply system. DT 2801 Hardware and MADCAP software were used to accomplish the Harmonic anylysis through forier transform.

The Dielectric Slab-Wedge Antenna, B. Keith Christensen

Theses

A theoretical model and numerical investigation of the directive gain of a dielectric slab-wedge radiator is presented. The model is based on a union of the classical dielectric slab equations, local mode theory, and equivalent current distribution treatments of the truncated dielectric slab and wedge geometries.

The far field is developed from the sum of two current distributions. The slab region, up to the transition plane between slab and wedge, is replaced by equivalent electric and magnetic surface current densities. The wedge contribution is developed from a volume polarization current distribution.

Conservation of power is used to approximate the field …

On-Line Analysis Of Highly Coherent Brain Activity During Transcendental Meditation And Automated Biofeedback, Deepak Dinkerrai Rawal

Theses

Occurance of highly coherent brain activity (EEG) specific to the meditation has been reported in the literature. The present thesis is an effort to look into the mechanics of meditation using the recent technique of analysis of high coherence in the EEG. Based on previous work, reporting increased EEG coherence during practice of Transcendental Meditation, a closed loop model and hypothesis is proposed using biofeedback to close the loop. The hypothesis proposes that very high coherence in the EEG is a very significant neurophysiological parameter, reflecting instantaneous quality of meditation in the form of an average high coherence above threshold. …

Replacement Of Surface Ducted Rays Near Caustics With Guassian Beams, Carlos Javier Ruiz

Theses

Conventional approach to a solution of a wave propagation problem in an inhomogeneous medium is to utilize either rays or modes to represent the wave field. Asymptotic ray theory (ART) starts to fail in the vicinity of caustics due to rays experiencing many reflections. Even uniform representations do not properly correct this deficiency of rays when caustics start to pile up in the far range. One possible alternative is to replace these rays with modal bundles and remainders [1]. A promising technique using Gaussian Beams has been used to represent the total field due to a point or a line …

Design And Optimization Of Nmos Sense Amplifiers For Vlsi Drams, Nimish K. Shah

Theses

The aim of this thesis is to study and optimize the performance of NMOS sense amplifiers used in modern VLSI DRAMs.

Initially dynamic memory cells and popular sense amplifier circuits are surveyed.

A standard five transistor sense amplifier is later chosen for detailed analysis. Layout of the circuit is drawn to get the physical parameters. Using SPICE simulator, various effects of circuit parameters are studied. From these results optimal values of these parameters are arrived at.

Also an effort is made to derive theoretically equations for the latching time of a post amplifier which is the most important part in …

Ray And Beam Representation Of The Glancing Phenomena, Michael Sotiriou Vogas

Theses

Asymptotic ray theory (ART) is a widely used method dealing with problems of wave propagation in an inhomogeneous medium. The main deficiency of ART is in transition regions where rays near caustics, glancing and critical incidence fail to represent the actual wave field. Ray bundles in such transition regions have been successfully replaced with modal bundles and remainders El] in well defined profiles. However , in practical problems it is difficult to implement modal representations and almost impossible to express remainders. Recently emerging Gaussian beam method (GBM) has shown promising results in representing the total field produced by a source …

Multi-Channel Arrhythmia Analysis In The Clinical Exercise Electrocardiogram, Shi-Xiong Yang

Theses

This thesis studied methods of using 2 channel ECG signals for noise elimination and arrhythmia detection. Clinical data were recorded from patients stress tests and were stored on diskettes for off-line processing. Spatial velocity vector and noise estimation methods in addition to analog and digital filters were combined to remove the noise produced from different sources. Feature extraction and matched filter methods were employed for classification of normal and abnormal QRS complexs, while rhythm computing was used in addition for PVCs and other arrhythmia discrimination. This algorithm was tested on clinical stress test recordings and a computer simulated arrhythmia recording …

Design And Evaluation Of Performance For The Multi-Microprocessor System, Sang-Soo Lee

Theses

A tightly coupled multiple-microprocessor with two MPU's that can be run at different clock speeds has been built and tested. The method of interconnection for this multiprocessor is a timeshared common bus with shared memories having a tightly coupled architecture. The signal timipg of the multiprocessor system for different speeds has been investigated using a logic analyzer for simulation modeling. The desired timing results have been obtained. According to the timing results, the simulation model for the General Purpose Simulation System has been correctly designed and performance of the multiprocessor system for the various clock speeds has been evaluated by …

An 8052 Ah - Basic, Based Development System, Suresh Vishwanath Leley

Theses

This project exploits the latest in microcontrollers-an entire environment for developing and prototyping a microcontroller application. With one key chip, a little glue, and a Dumb terminal a powerful system is achieved at a vanishingly small cost. This "one chip" system is adequate for realizing a wide range of applications calling for a small computer or an embedded processor.

Besides economy of system cost, the turn around time from concept to functioning application can be extremely short, even when the development engineer is not particularly well acquainted with traditional assembly language and microprocessor development practices. This economy is achieved by …