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An Investigation Of Electrical And Optical Properties Of Reactively Sputtered Silicon Nitride And Amorphous Hydrogenated Silicon Thin Films, Tae Hoon Kim

Theses

Thin films of silicon nitride and amorphous hydrogenated silicon were prepared by radio frequency reactive sputter deposition and their properties optimized for their use as low temperature passivation coatings for optoelectronic devices. The effect of various sputter deposition parameters on the conduction and optical properties were studied. Infrared spectrophotometry and ellipsometry were used to determined the optical properties of the films whereas the electrical properties were determined from current-voltage measurements of MIS capacitors.

Typical parameters of a sputter deposition run for the best Si₃N₄ films were: base pressure, 1-2x10^-6 torr; sputtering pressure, 5 mtorr; nitrogen partial …

Design Of A Fiber Optic Oxygen Sensor Based On Immobilized Hemoglobin, Mendu Govind Raj

Theses

The fiber optic Oxygen sensor consists of a thin layer of immobilized deoxyhemoglobin at the common end of a bifurcated fiber. Immobilization is done using the alginate gel procedure. The immobilized reagent is separated from the standard oxygen sample by the gel with or without semi-permeable membrane, and the entire configuration is enclosed in an oxygen free sample cell. Light from a tungsten-halogen lamp, filtered through a 405nm filter is passed through one arm of a bifurcated fiber to the sample cell. The reflected intensity (a highly polished aluminum foil or a plate is placed at the bottom of the …

Rf Characterization Of A Directly Modulated Ingaasp Buried Heterostructure Laser Diode, Charlotte Alvarez

Theses

The use of fiber optics for the transmission of microwave signals had its beginnings in 1984. Applications were limited to the lower microwave frequency regions. Technology in this field is advancing rapidly due to the high demand driven by the telecommunications community for high speed digital applications. Extensive research and development efforts are underway by both the component manufacturers and the subsystem end user. Most of the near term applications of microwaves in fiber optics are in weapon systems and communication systems for military and other government agencies.

The high frequency modulation characteristics of Lytel's InGaAsP 1300 nm buried heterostructure …

Design Of Bridge Inter-Connecting Token Ring & Token Bus Local Area Networks, Kasinath Anupindi

Theses

A Bridge interconnecting two Local Area Networks has been modelled. The two interconnected networks are the Token Ring and the Token Bus LANs. Concepts of Queueing theory have been employed in the design. Initially it is assumed that the buffer size at the Bridge is infinite. Further it is assumed that the arrival rate of the messages is Markovian and the service rate is General, Le it is an M/G/1 system. Expressions for the average waiting time at the Bridge and the size of the buffers is computed. Graphs for various parameters have been plotted. Based on these graphs the …

Data Flow Dependency Generator, Chin-Piao Chan

Theses

Data flow is a new approach to parallel computing. The concept is to enable the execution of an instruction whenever its operands become available. The only constraints in a data flow machine are the data flow dependencies between instructions.

In this thesis, a simulation package called the Data Flow Dependency Generator is developed. This package is designed to express the idea of data flow computations, the data flow dependencies and the use of multiprocessors.

Given a number of processors, a number of time units for each operation and a program, the Data Flow Dependency Generator finds the data dependencies between …

Stepping Motor Control And Position Monitoring, Pei-Kuan Feng

Theses

Stepping motors provide precise digital control of speed, without speed detector feedback. A stepping motor can produce a large torque for a relatively small displacement, without a shaft-position sensor or special compensation. This provides accurate control of motor position. This thesis describes the development of stepping motor torque characteristics and the different approaches stepping motor phase current waveform detection. It is shown that one of the most useful indicators of rotor position is the initial rate of current rise. The Hybrid, Permanent-magnet and Variable-reluctance step motors have been applied in the drive circuits. The open-loop control circuits are implemented to …

An Investigation Of Interrupt Handling Schemes In Pipeline Processors, Shailesh Ratilal Gami

Theses

In order to acheive higher performance in a pipeline processor, proper interrupt handling is essential. In a pipeline processor, interrupt handling is difficult because many instructions are in the processor at the same time. This study describes and evaluates the different solutions to interrupt handling. Several pipelined 32-bit microprocessors have also been studied and their architectural and programming features are compared.

The Application Of Zero-Sum Games To Low Sensitivity Optimal Control, Jun Huang

Theses

This thesis deals with the synthesis of low sensitivity optimal control systems. Zero-Sum games are applied to the first order linear differential equation system. The goal is to obtain an optimal control of the system performance, and at the same time, reduce the sensitivity of the performance index and sensitivity trajectory.

In this thesis, the quadratic index of performance is selected in the argumented system which is combined/ the system equation with the sensitivity equation. Two control variables U & V are selected to maximize and minimize the system, in order to obtain the optimal value of the system.

Two …

Reliability Of Packaging In Microcircuits, Zia Iqbal

Theses

The semiconductor industry is faced with the problems of how to increase the level of reliability of semiconductor parts being used in the electronic systems which have had their lifetimes extended through new and better system design.

This paper deals with the reliability of packaging constructions commonly used in large scale integration / integrated circuits and will present the failure mechanisms and failure modes which can arise when proper processing is used. In addition, the materials used in each construction and how they affect reliabilty will be analyzed.

It is not the intention of this paper to present any new, …

Failure Mechanisms Of Hermetically Sealed Solid Tantalum Capacitors, Syed R. Kazmi

Theses

This study has determined the failure mechanisms of solid tantalum capacitors and their causes. It was observed that high leakage current and electric shorts are the most prominant modes of failure. The experimental data has proved that humidity and high temperature are the factors which promote these kinds of failures. It is also stablished that change in electrical parameters due to exposure to harsh weather are reversible. Vacuum treatment to such capacitors helped in improving their electrical characteristics.

Apap: The Arithmetic Pipeline Analysis Package, Chang-Chieh Lin

Theses

This study is aimed at the development of an interactive PC-based package for simulating data flow within an arithmetic pipeline in multiprocessor systems. The user constructs the arithmetic pipeline, specifying the functionality of each segment, the intersegment connectivity and pipeline inputs and outputs. After defining reservation tables and data, analysis is performed with the results available in tabular, simple graphic and animated graphic forms.

APAP allows the user to design hardware and analyze its functionality with-out building the circuit, an economical alternative. Even when circuits are to be built, APAP allows the user to correct logic errors before implementation, leaving …

Gallium Arsenide Standard Cell Cad Database For Digital Design, Nanchou Liu

Theses

This thesis develops a selected design database of gallium arsenide logic cells for automated design. Uniformly applied 1 um gate length physical layout rules are used for the design database with a standard cell design methodology.

Schottky Diode FET Logic (SDFL) technology with double level metallization was selected following a consideration of alternative gallium arsenide MESFET logic types. The SDFL approach is judged to provide improved noise margin, production yield, density, and lower power dissipation.

A cell library with 60 um cell height has been implemented with double entry for each cell input/output. Each cel1 has been simulated with SPICE …

Contrast Sensitivity Measurement Via Evoked Potential, Ken-Gen Lu

Theses

This work is concerned with the use of the visual Evoked Response (VER) to determine Contrast Sensitivity in humans. For this purpose, a system has been developed where signals, obtained from scalp electrodes, and stimulated by visual grating patterns, are recorded digitized and processed on a personal computer (IBM compatible). Processing includes signal averaging and digital filtering. The system provides storage, retrieval and graphic representation of data as well as the capability to transfer data to other computer systems. Data processing includes parameter estimation of suitable signal models, which provide effective data compression of the signal into a finite set …

Interface To 8052ah-Basic Microcontroller For A Multichannel Priority Interrupt System, Chen-Tung Mo

Theses

This thesis presents the design and development of a system with the capability to detect up to forty channels of signals generated from different analog sources and to process them under the control of a microcomputer.

The present work offers the design and implementation of a hardware interface unit in a multichannel real-time data acquisition system as well as the application software program to operate it. This kind of system can be widely used in process control, musical instrument interfacing, and machine automation.

This interface unit follows the general instrumentation architecture in both signal processing and logic control. The software …

A Dynamic Set-Based Multiaccess Protocol For Local Area Networks, Parul S. Nanavati

Theses

The packet-broadcasting technique brings together the advantages of both packet switching and broadcast communication. The central problem of a packet broadcast network is conflict resolution among the users sharing the broadcast communication link. Collisions are the major source of transmission errors which degrade the performance of a LAN. Proposed here is a novel multiaccess protocol which offers full communication resources to the user at low traffic requirements. It dynamically adjusts the number of users allowed to access the medium at heavy traffic requirements such that number of collisions are reduced and thus maintains the efficient utilization of the medium and …

Design Criteria Of Coherent Optical Fiber Communication System, Rajesh N. Patel

Theses

Design criteria of coherent optical fiber communication system were discussed and investigated. First, the different types of optical fibers (waveguides) were discussed. Then the laser sources, photo-detectors, transmitter & receiver circuits were discussed in detail.

Design criteria of conventional intensity modulated (direct detection) optical fiber communication system were discussed. Then, the design criteria and estimation of number of photons for different modulation schemes for coherent optical fiber communication system were analyzed.

Coherent optical fiber communication system's advantages and drawbacks were discussed in detail. Improvement in receiver sensitivity of coherent detection compare with conventional direct detection was investigated. Finally, some receiver …

Microprocessor Testing And Computer Aided Diagnosability Of Digital Circuits, Shirish Patel

Theses

Computer Aided Diagnosability Of Circuits (CADOC), a new method is developed for isolating and pin-pointing a faulty device in digital circuits. CADOC is based on graph-theoretic principle and PFD numbers. Without considering any SA1 or SAO faults, we can zoom out faulty device by selecting different diagnostic path to narrow down the faulty region and to isolate the faulty device. The efficiency of this new technique is confirmed by applying the technique to many examples.

Design And Development Of An Infrared Ccd Camera, John Frederick Romanowich

Theses

An infrared CCD camera system was designed and developed for operating various sizes of Schottky-barrier IR-CCD image sensor chips. The camera has a digitally programmable frequency synthesizer for operating the 160 X 244, 320 X 244, and 256 X 256 image sensors developed at the David Sarnoff Research Center. The electronics of the camera are designed to provide the outputs required for operating a XYZ monitor, a standard TV monitor, or a computer workstation. At the core of the camera design is a RS-170 standard sync generator that supplies the waveforms for synchronizing the camera's circuitry to produce a composite …

An Investigation Of Electrical And Physical Properties Of Reactively, Diode Sputtered Silicon Nitride Thin Films, Divyang Manharlal Shah

Theses

Silicon nitride thin films were deposited by r.f. reactive sputtering of silicon in nitrogen and argon discharge. Biased and unbiased modes of diode mode sputtering were used. Typical parameters for a sputter deposition run were: base pressure, 1-2x10-6 torr; sputtering pressure, 5-7 mtorr; nitrogen partial pressure, 15-16%; cathode-anode gap, 4 inch; r.f. power, 200-250 watts; cathode voltage, 1.8-2.1 V r.f.; water vapor pressure, 20-30% of the base pressure. The film thickness and the refractive index were measured by ellipsometery. The films of thickness 300-2500A, refractive index 1.9-2.1 and resistivity 10101Ω — cm were obtained. The deposition rate was in the …

Design Of An Experimental Apparatus To Measure The Charge And Mass Of Ionized Species In A Partially Ionized Cluster Beam Deposition System, Nitin K. Shah

Theses

The objective of this research was the design and construction of an experimental apparatus to investigate the size distribution of gallium clusters that can be emitted from a heated crucible with a 1 mm nozzle. This research work involved the design and construction of a partially ionized cluster beam (PICB) deposition system which would provide low charged particle background for retarding field analysis and cluster size measurements. The apparatus also allowed control of critical parameters on which the cluster size may depend.

The promise of PICB is based on the formation of clusters of adatoms, their ionization and their acceleration …

A Computer-Based Microwave Interferometer Instrumentation System As A Non-Invasive Cardiopulmonary Monitor, Chin-Yee Eric Ho

Theses

The system comprises a microwave interferometer as a computer-based non-invasive cardiopulmonary monitor. The microwave interferometer records the mechanical vibration of the chest wall. The objective is to determine whether the signals may have diagnostic value and to evaluate the instrument as a non-invasive and non-contacting cardiopulmonary monitor.

With the help of a computer it is possible to analyze the mechanical vibration of the chest wall produced by the heart and thereby detect, and possibly categorize, cardiac abnormalities. This system is able to process two channels, the first signal from microwave interferometer records chest wall vibrations and the second signal is …

Reliability Problems In Semiconductor Lasers, Ajay R. Patel

Theses

The stability and reliability of semiconductor laser is dependent on its design, fabrication, and output power. The best way to assure high reliability of these devices is by accelerated aging test and by selection of strict and meaningful criteria for the acceptance or rejection of a particular device. In this thesis emphasis is given on different failure mechanisms that are known. As new development takes place, other mechanisms may be found. Catastrophic degradation, gradual degradation, darkline defects, and contamination during the fabrication process are the main source of device failure.

The noise generation and the packaging issue of semiconductor laser …

Temperature Dependent Reliability Of Plastic Packaged Microcircuits, Wasim Ahmed

Theses

Increasing power and power densities in new high complexity semiconductor devices are creating heat removal problems. Increased powers produce higher junction temperature which lead to potentially faster degradation of device reliability. Thermal management at device level packaging involves efficient and cost-effective removal of dissipated thermal energy from the device to assure its reliable performance over the long term. In the context of very high levels of integeration of future ICs, thermal management will mean making such devices possible close to the limits of acceptable high temperature.

The major factors affecting heat flow in a plastic Dual-in-line-packages (DIP'S) are investigated using …

Development Of 8052ah-Basic Based Single Board Computer Ii, Suping Lou

Theses

8052AH-BAISC Based Single Board Computer II ( SBC II ) is designed and developed for the application in biomedical instruments as an embedded central processing unit. SBC II offers powerful function in digital signal acquisition, storage and processing, smart on-board EPROM programming, various preipheries supporting and custom supervisor program. The techniques of design and development of SBC II includes computer aided circuits analysis and schematic, optimal design algorithms and computerized setting up SBC II prototype.

This thesis combines the analysis of SBC II circuitry, set up and operation of the complete computer aided electrical circuit design software OrCAD/SDT specifics in …

Implementation Of The Voice Processing System, Yang-Young Dan

Theses

The Voice Processing System is implemented by using XILINX Advanced Computer Aided Design Technology. It is also used as an interface to the 8052 AH-BASIC single hoard computer system.

The Voice Processing System ( VPS ) comprises three major parts:

1. Voice Detection Circuit

2. System Clock Generation & Synchronization

3. Signal Processing and Storing Circuit

The analog voice sip!gnals are the inputs to the first part of VPS. The digitalized voice is the output of this system.

In order to get precise output, the first part plays the roles of noise cancellation, zero crossing processing, and recognition.

For the …

Image Enhancement And Edge Detection Using Fuzzy Algorithm, Samir Patel

Theses

A method of image enhancement and edge detection by computer using the fuzzy set is illustrated. The algorithm involves extraction of fuzzy properties corresponding to pixels and then succesive application of fuzzy operator 'contrast intensification' along with smoothing in the fuzzy property plane before detecting its edges. The property plane is extracted from the spatial domain using S, π, and (1- π) functions and the fuzzifiers. Edge detection is achieved using KIRSH operator. A computer routine is developed and the effectiveness of the algorithm with different value of the system parameter is demonstrated on different images. The digital computer HP …

Analysis And Simulation Of Chirp Radar System, Tina Tsung Tsai

Theses

This paper consists of a technique to design a Chirp radar system and proposes a solution to optimize the design of the linear time delay network required in such systems. A Chirp radar system has a wide bandwidth for high range resolution, and long pulse duration for high velocity resolution and high transmitted energy. The technique of a pulse compression system offers a means of increasing the average power available to illuminate radar targets without any loss of the resolution at the receiver needed for the tactical requirements of the system. This is accomplished by transmitting a wide pulse in …

High Frequency Gaussian Beams Solution Of A Plane Wave Coupling Into Cylindrical Cavity, Christine Issa Mourad

Theses

Propagation of high frequency fields as a superposition of Gaussian beams instead of geometrical ray fields has potential advantages in complicated environments because the beams do not fail in ray optic transition regions. While the Gaussian beam method can be made rigorous through self consistent stacking of displaced and tilted beams on a Gabor phase space lattice, with retention of full beam spectra, computation is facilitated when the propagation domain is covered with paraxially approximated nontilted beams. The spectral deficiencies introduced by this simplified propagation model depend on the propagation environment. They are examined here for a plane wave coupling …

A 100-Khz - 22 Ghz Instrumentation Photoreceiver, Dennis J. Derickson, C. M. Miller, R. L. Van Tuyl

Electrical Engineering

A photoreceiver consisting of a high-speed p-i-n photodetector and a 100-kHz to 22-GHz distributed amplifier is described. Photoreceiver calibration is accomplished by optical heterodyne techniques. The photoreceiver is used with a microwave spectrum analyzer to produce a fully amplitude-calibrated 22-GHz-bandwidth lightwave signal analyzer system for displaying intensity-modulated light with -65-dB (optical) sensitivity at 1300-nm and 1550-nm wavelengths.

Implementing Ray Tracing Algorithm In Parallel Environment, Tjah Jadi

Dissertations and Theses

Ray tracing is a very popular rendering algorithm in the field of computer graphics because it can generate highly-realistic images from three-dimensional models. Unfortunately, the computational cost is very expensive. To speed up the rendering process we present both static and dynamic scheduling (balancing) strategies for a multiprocessor system. Hence, the load balancing among the processors is the most important problem in parallel processing. The implementation of the algorithm is based on a modified octree structure.