Engineering Commons^™

Conditional Artificial Dielectric : Optically Controlled Microwave Modulator, J. Manuel Jimenez

Theses

A conditional artificial dielectric with embeddings of either CdS, GaAs or Si in PMMA form the dielectric material of a microstrip in a homodyne microwave detection system. The system consists of a Michelson or Mach-Zehnder interferometers with the microstrip placed in one arm. The index of refraction of the microstrip substrate is modulated by chopped incident light causing amplitude and phase variations in the incoming RF signal. Those variations are detected by mixing the light modulated microwave carrier(information channel) with the unmodulated carrier (reference channel) in the interferometer. The output is sensed by the square law detector and a lock-in …

Efficient Hypercube Communications, Shreyas R. Bhatt

Theses

Hypercube algorithms may be developed for a variety of communication-intensive tasks such as sending a message from one node to another, broadcasting a message from one node to all others, broadcasting a message from each node to all others, all-to-all personalized communication, one-to-all personalized communication, and exchanging messages between nodes via fixed permutations. All these communication patterns are special cases of many-to-many personalized communication. The problem of many-to-many personalized communication is investigated here.

Two routing algorithms for many-to-many personalized communication are presented here. The algorithms proposed yield very high performance with respect to the number of time steps and packet …

Improved Crystalline Quality Of Si1-XGeX Formed By Low-Temperature Germanium Ion Implantation, Ken-Ichi Shoji, Akira Fukami, Takahiro Nagano, Takashi Tokuyama, Cary Y. Yang

Electrical and Computer Engineering

Improvement of crystalline quality in Si_1-xGe_x formed by germanium ion implantation has been found. End‐of‐range defects were drastically reduced in number by lowering the substrate temperature during implantation with doses on the order of 1016 cm−2. This improvement was confirmed by electrical characterization of p‐n junctions formed in the SiGe layer as well as by transmission electron microscopy.

All Optical Synchronisation With Frequency Division Using A Self Pulsating Laser Diode, Gerald Farrell, P. Phelan, Joe Hegarty

Articles

A master optical clock from a mode locked laser is distributed to two slave twin section lasers. One slave laser divides the optical modulation frequency by 2, the other slave laser multiplies the frequency by 2. It is also possible to vary the multiplication4ivision ratio in a slave laser using only DC control of the absorber of the twin section laser.

All Optical Clock Distribution With Synchronous Frequency Division And Multiplication, Gerald Farrell, P. Phelan, Joe Hegarty

Articles

A master optical clock from a mode locked laser is distributed to two slave twin section lasers. One slave laser divides the optical modulation frequency by 2, the other slave laser multiplies the frequency by 2. It is also possible to vary the multiplication4ivision ratio in a slave laser using only DC control of the absorber of the twin section laser.

Translation Of 'Kamalakanta: A Collection Of Satirical Essays And Reflections', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

This venture was born initially out of the desire to make those works of Bengali literature which have moved me profoundly, and which I consider first-rate by any yardstick, available to friends and fellow enthusiasts who cannot read the original. In attempting to channel literary and philosophical masterpieces into a different medium, I Have experienced firsthand the formidable challenge that a translator must face because not only of the barrier imposed by the languages involved, but perhaps more so because .of his or her own severely inadequate faculty being called upon to match both the genius and the inspiration of …

Unequal Error Protection Qpsk Modulation Codes, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

The authors use binary linear UEP (LUEP) codes, in combination with a QPSK signal set and Gray mapping, to obtain new efficient block QPSK modulation codes with unequal minimum squared Euclidean distances. They give several examples of codes that have the same minimum squared Euclidean distance as the best QPSK modulation codes of the same rate and length. A new suboptimal two-stage soft-decision decoding is applied to LUEP QPSK modulation codes.

Photonics In Switching, Harvard S. Hinton

Electrical and Computer Engineering Faculty Publications

One of the keys to the future of telecommunications companies will be their ability to provide new broadband services to both the business community and residential customers. With the new services will come the need for the equivalent of a broadband switching office. Such a system could require the capability of supporting in excess of 10000 users with broadband channel bit rates exceeding 100 Mb/s. This implies a switching fabric the aggregate bit rate of which could be greater than 1 Tb/s. Guided-wave technology and free-space technology switching fabrics are discussed. Three time-division-based switching fabrics are proposed, and two wavelength-division-based …

Switching To Photonics, Harvard S. Hinton

Electrical and Computer Engineering Faculty Publications

The use of hardware that exploits the interplay of photons and electrons to switch voice, data, and video is discussed. The two directions being taken by current research-guided-wave and free-space photonics-are examined. Photonic time-slot interchanges are described. Multidivisional fabrics, based on a combination of space-division and time-division multiplexing, are considered, as is the wavelength-division-based photonic packet switch, another kind of multidimensional fabric. The use of self-electrooptic effect devices, (SEEDs) is discussed.

All-Optical Synchronisation And Multiplication Of The Frequency Of Mode-Locked Signals, P. Phelan, Gerald Farrell, Joe Hegarty

Articles

We report all-optical synchronized multiplication by rational fractions of the modulation frequency of optical signals in self-pulsing two-section semiconductor laser diodes. The effect is based on the overlap of harmonics of the input signal with harmonics of the self-pulsation. We illustrate this new generic function with modelocked inputs rich in harmonics were fractions of 1,2, and 3 / 2 are generated, and we identify a number of applications for this effect.

A Demonstration Of Machine Control Using The Slc-150 Microprocessor Programmable Controller, Mike Courts, Richard Schmitz

Graduate Student Work

This project will use an Allen-Bradley SLC-150 microprocessor programmable controller to demonstrate an actual application being used in industry. The SLC-150 will be used to sequentially control a Pelco pan and tilt drive unit. This unit is mounted with a video camera that is used for security monitoring. The SLC-150 will also control the cameras zooming features.

Prior to microprocessors the electrical control of machines used input devices such as push buttons and limit switches connected to magnetically hard wired relay logic. Hard wiring meant that electrical wires were connected between all relay coils and contacts, making up what is …

Electromagnetic Focusing Properties Of Chirped Metallic Gratings, Jeffrey C. Schmidt

Retrospective Theses and Dissertations

The focusing properties of chirped diffraction gratings have long been studied and often used in applications at optical frequencies. Chirped metallic gratings of this type have also been studied theoretically at microwave frequencies, but no attempt has been made to experimentally examine or utilize the focusing properties of these structures at microwave frequencies. This thesis presents an experimental analysis of the focusing properties of chirped metallic gratings. These gratings are designed to focus electromagnetic energy at a predetermined position by varying strip width and spacing as a function of position. The diffraction gratings are characterized, and experimentally measured results are …

Acuta: A Case For Change

ACUTA: Other Publications

In This Issue

Preface

Executive Summary

Societal Trends

The Information Age

The University of the 21st Century

Implications for Telecommunications Administrators

Studies Of High Field Conduction In Diamond For Electron Beam Controlled Switching, R. P. Joshi, M. K. Kennedy, K. H. Schoenbach, W. W. Hofer

Bioelectrics Publications

Experimental studies on a vertical metal‐diamond‐silicon switch structure have been conducted for potential pulsed power applications. Both the dc current‐voltage characteristics and the transient switching response have been measured for a range of voltages. With a 1 μm diamond film, the switch has been seen to withstand electric fields up to 1.8 MV/cm. Our results show a polarity dependence which can be associated with current injection at the asymmetric contacts. Polarity effects were also observed in the presence of e‐beam excitation, and arise due to nonuniform carrier generation near the diamond‐silicon interface. Our switching transients were seen to follow …

Bistable Behavior Of The Dark Current In Copper-Doped Semi-Insulating Gallium Arsenide, R. A. Roush, K. H. Schoenbach, R. P. Brinkmann

Bioelectrics Publications

The dark current characteristics of gallium arsenide doped with silicon and compensated with diffused copper were found to have a pronounced region of current controlled negative differential conductivity (ndc) similar to the characteristics of a thyristor. The resistivity of the semi‐insulating semiconductor was measured to be 10⁵ Ω cm for applied voltages up to 2.2 kV, which corresponds to an average electric field of 38 kV/cm. At higher voltages, a transition to a stable high current state was observed with a current rate of rise exceeding 10¹¹ A/s. There is evidence of the formation of at least one …

An Optical Adaptive Resonance Neural Network Utilizing Phase Conjugation, Donald C. Wunsch, D. J. Morris, T. P. Caudell, R. A. Falk

Electrical and Computer Engineering Faculty Research & Creative Works

An adaptive resonance (ART) device has been conceived that is fully optical in the input-output processing path. It is based on holographic information processing in a phase-conjugating crystal. This sets up an associative pattern retrieval in a resonating loop utilizing angle-multiplexed reference beams for pattern classification. A reset mechanism is used to reject any given beam, allowing an ART search strategy. The design is similar to an existing nonlearning optical associative memory, but it does allow learning and makes use of information the other device discards. This device is expected to offer higher information storage density than alternative ART implementations.

Efficient Simulation Of Multi-Carrier Digital Communication Systems In Nonlinear Channel Environments, K. W. Schneider, William H. Tranter

Electrical and Computer Engineering Faculty Research & Creative Works

For systems that contain both frequency division multiplexing and bandpass nonlinearities, the high sampling rate that is necessary for accurate simulation contributes to the long runtimes. A partial sum of products (ParSOP) method is proposed to reduce the sampling rate of such systems. The ParSOP method allows the simulation sampling frequency to be reduced by only generating those intermodulation products that are centered in the bandwidth of the single observed modulated subcarrier. Simulation results, obtained by using the complex power series nonlinear model on a filtered binary phase shift keying system, showed that a reduction in the simulation runtime by …

The Error Probability Of Reed-Solomon Coding And Interleaving On A Bursty-Noise Channel, W. J. Ebel, William H. Tranter

Electrical and Computer Engineering Faculty Research & Creative Works

A useful bursty-noise channel model is proposed and, using this model, a binary communication system using Reed-Solomon coding and interleaving is analyzed. The model includes both thermal noise, which gives rise to random errors, and burst noise, which gives rise to error bursts. Error probabilities are derived for the uncoded system, and error probability bounds are derived for the coded system. Monte Carlo simulation results agree well with theory.

New Emc Design Guidelines For Multilayer Printed Wiring Boards, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Principal Linear Polarization States Of An Optical System, R. M.A. Azzam

Electrical Engineering Faculty Publications

The constraint on the Jones matrix of an optical system such that there exist two linear polarization states at its input that are mapped onto two corresponding linear states at its output is derived. These principal linear polarization (PLP) states, which characterize a broad range of systems, are also found in terms of the Jones matrix elements. Special cases when the PLP states are orthogonal, collapse onto one state, or become infinite in number are indicated. For a deterministic or nondeterministic optical system described by a Mueller matrix, the existence of two PLP states places a constraint on only 3 …

Spontaneous Coherent Pulsations In Standing-Wave Laser Oscillators : Stability Criteria, Pitak Chenkosol

Dissertations and Theses

The stability criteria for single-mode standing-wave laser oscillators in the strongly homogeneously broadened limit are reported for the first time. Two types of stability criteria are presented. The first type, called type 1, corresponds to the minimum value of threshold parameter for which an infinitesimal perturbation away from steady state grows into an oscillatory solution. Another type of stability criteria, called type 2, corresponds to the minimum value of threshold parameter for which large amplitude oscillatory solutions do not decay to the steady state solution. Undamped pulsations in single mode strongly homogeneously broadened standing-wave laser oscillators are found to occur …

A Partitioning-Based Approach To The Fitting Problem In Special Architecture Eplds, Steffan Goller

Dissertations and Theses

In this thesis, we describe an architecture-driven fitting algorithm for an Application-Specific EPLD, the CY7C361, from Cypress Semiconductor. Traditional placement and routing tools for PLDs perform placement and routing separately. Several placement possibilities are created and the router tries to realize the connections between the physical locations of the cells on the chip. The Cypress CY7C361 has a very unique chip architecture with a highly limited connectivity between the physical cells. Therefore, it is necessary to consider the mutability when the placement of cells is performed. The combination of the two stages is called fitting. The specific architecture-dependent constraints, imposed …

A New Method For Calculating The Economic Benefits Of Varying Degrees Of Power Factor Correction For Industrial Plant Loads, Mohammed Ishaque

Dissertations and Theses

A comparative study of the economic benefits that can be obtained from different degrees of power factor correction for medium and small scale industrial installations is shown. A new approach for precise calculation of kws and kvars required at different power factors is presented. These calculated values are used to find the return on investments for the capacitors needed for power factor correction. The developed method is easy to use, cost effective, accurate and will help electrical engineers with minimum knowledge of power systems to precisely determine the savings available by improving the power factor of an industrial load.

Performance Analysis Of Doa Estimation Algorithms Using Physical Parameters, Hui Liu

Dissertations and Theses

Analytical performance analysis on Direction-Of-Arrival (DOA) estimation algorithms has attracted much excellent research in recent years, various statistical properties have been revealed. However, in most of these analyses, insights of the performance were masked because of the involvement of singular values and singular vectors which depend on the character of the algorithms and data structures in a complex and nonlinear manner.

Characterization Of Quantization Noise In Oversampled Analog To Digital Converters, Eric W. Multanen

Dissertations and Theses

The analog to digital converter (ADC) samples a continuous analog signal and produces a stream of digital words which approximate the analog signal. The conversion process introduces noise into the digital signal. In the case of an ideal ADC, where all noise sources are ignored, the noise due to the quantization process remains. The resolution of the ADC is defined by how many bits are in the digital output word. The amount of quantization noise is clearly related to the resolution of the ADC. Reducing the quantization noise results in higher effective resolution.

Multiplexed Pipelining : A Cost Effective Loop Transformation Technique, Satish Pai

Dissertations and Theses

Parallel processing has gained increasing importance over the last few years. A key aim of parallel processing is to improve the execution times of scientific programs by mapping them to many processors. Loops form an important part of most computational programs and must be processed efficiently to get superior performance in terms of execution times. Important examples of such programs include graphics algorithms, matrix operations (which are used in signal processing and image processing applications), particle simulation, and other scientific applications. Pipelining uses overlapped parallelism to efficiently reduce execution time.

Bulletin No 4131- Electric Fencing, Dean Maughan

Bulletins 4000 -

Fencing has always been an integral part of our agricultural system. We need fences for stock control and pasture management. Traditionally, fences have been strong and robust physical barriers. The strength and height of the fence kept domestic animals confined. For many years, conventional fences have served the farmer well. However because returns from livestock over the past ten years have been variable and because of the current cost/ price squeeze, electric fencing, as a cheaper form of fencing, has gained popularity.

Coperite-Computer-Aided Tool For Power Engineering Research, Instruction, Training And Education, Badrul H. Chowdhury, D. E. Clark

Electrical and Computer Engineering Faculty Research & Creative Works

A graphics-oriented, primarily PC-based tool for education, research, and training in power engineering is introduced. The tool, called COPERITE, has all user interfaces resident on an IBM-386 microcomputer. Menus and windows are used for the interface, and attractive graphical representations and displays are included. Application programs that are interfaced are power flow, contingency analysis, economic dispatch, security-constrained dispatch, system stability, and fault analysis. These programs are executed on a VAX 8800 computer mainly for speed of execution. Information exchange between the PC and the VAX is made through an Ethernet connection which is transparent to the user. Results of execution …

An Optical Implementation Of Adaptive Resonance Utilizing Phase Conjugation, Donald C. Wunsch, T. P. Caudell, D. J. Morris, R. A. Falk

Electrical and Computer Engineering Faculty Research & Creative Works

A novel adaptive resonance theory (ART) device has been conceived that is fully optical in the input-output processing path. This device is based on holographic information processing in a phase-conjugating crystal. This sets up an associative pattern retrieval in a resonating loop utilizing angle-multiplexed reference beams for pattern classification. A reset mechanism is used to reject any given beam, allowing an ART search strategy. The design is similar to that of an existing nonlearning optical associative memory, but is does allow learning and makes use of information the other device discards. This new device is expected to offer higher information …

Object-Based Analog Vlsi Vision Circuits, C. Koch, B. Mathur, S. C. Liu, J. G. Harris, J. Luo, M. Sivilotti

Electrical and Computer Engineering Faculty Research & Creative Works

Early vision algorithms typically can be classified as either pixel-based or image-based. Pixel-based algorithms such as edge detection and optical flow produce a dense output on every grid point. Image-level algorithms such as center of mass computation [1,5] produce a few outputs by integrating information from the entire image. Most special-purpose analog VLSI vision chips developed so far implement early vision algorithms of these categories. Little work has been done in building special-purpose chips that move beyond these early-vision algorithms. Dynamic wires, first introduced by Liu and Harris [2], provide an avenue for object-based processing. The dynamic wire model is …