Coplanar microstrip structures placed on dielectric substrates
are used as high frequency electro-optic modulators. The method of
lines, a mathematical technique for solving partial differential
equations, has been applied to solve for the propagation
characteristics of such a configuration.
It has been determined that simple transmission line models
are adequate...
This thesis covers the efforts of the design, analysis,
characteristics, and construction of a Linear Brush less Doubly-Fed
Machine (LBDFM), as well as the results of the investigations and
comparison with its actual prototype.
In recent years, attempts to develop new means of high-speed,
efficient transportation have led to considerable...
An electro-dynamic Magnetic Levitation vehicular system has been
modelled and studied. In practice, a MagLev vehicle will consist of a
number of cars which are mechanically coupled to each other. It is
reasonable to assume that each of these cars will be independently
controlled with the help of a supervisory...
Computers using the tagged-token dataflow model are among the best candidates for delivering extremely high levels of performance required in the future. Instruction scheduling in these computers is determined by associatively matching data-bearing tokens in a Waiting-Matching Unit (W-M unit). At the W-M unit, incoming tokens with matching contexts are...
The problem of the restoration of quadratically
distorted images is considered in this investigation, based
upon the fact that images formed by partially coherent
illuminations are related quadratically to the amplitude of
the object. Two of the most important problems in image
restoration are: 1) determining the degradation
characteristics of...
A brushless doubly-fed machine (BDFM) is a single-frame, self-cascaded
induction machine capable of operating in both the induction
and the synchronous modes. This thesis presents some important
advances concerning dynamic modeling, simulation and analysis of the
BDFM.
Initially, a two-axis model and its associated parameters are developed
and calculated. The...
A foundation for the control of tumors is presented,
based upon the formulation of a realistic, knowledge-based
mathematical model of the interaction between tumor cells
and the immune system. The parametric control variables
relevant to the latest experimental data, e.g., the sigmoidal
dose-response relationship and Michaelis-Menten dynamics,
are also considered....
A complete Gallium Arsenide Metal Semiconconductor
Field Effect Transistor (GaAs MESFET) model including deep-level
trap effects has been developed, which is far more
accurate than previous equivalent circuit models, for high-speed
applications in linear integrated circuit design.
A new self-backgating GaAs MESFET model, which can
simulate low frequency anomalies, is...
High speed photodetectors are a necessary element in
broad band digital and analog optical communication systems.
In this thesis easily integrable planar high speed
photodetectors made on undoped semi-insulating (SI) GaAs
substrates are modeled and tested. The fabrication process
of the detectors is fully compatible with GaAs
metal-semiconductor field effect...
Oversampled data converters are becoming increasingly popular
for high-precision data conversion. There have been many
publications on oversampled analog-to-digital (A/D) converters but
relatively few on oversampled digital-to-analog (D/A) converters.
In this thesis, issues concerning the analysis and design of the
oversampled D/A converters are addressed. Simulation tools and
analytical methods...
Generalized modal analysis techniques for the characterization and modeling of dissipationless planar waveguide structures and discontinuities encountered in microwave and optical integrated circuits, as well as of quantum waveguide structures and devices, are presented. The frequency-dependent transmission properties of the curved microstrip bend are derived by utilizing a second-order perturbation...
This thesis presents an adaptive model reference controller for a highly
maneuverable high performance aircraft, in particular, a modified F18. An adaptive
controller is developed to maneuver an aircraft at a high angle of attack. Thus, the
aircraft is required to fly over a highly nonlinear flight regime. The adaptive...
In this paper, an analysis of the clock-feedthrough effects in
switched-current (SI)' circuits will be presented. The clock-feedthrough
effects caused by the non-ideal characteristic of MOS
switches when they are turned off limit the accuracy of the analog
track-and-hold (T/H) circuits. A model to analyze and characterize this
effect is...
This thesis describes the development of a flash analog-to-digital converter based on
current-mode technique. The advantages of current -mode technique are higher speed,
smaller chip area, and simple division of reference current based on current mirror. A
current-mode comparator is designed consisting of a cascode current mirror and a
current...
Environmental concerns have renewed the interest in electric vehicles. To gain
widespread use, electric vehicles will also have to offer good performance and be
reasonably priced. AC drive systems using modern semiconductors can provide
efficient operation at the required power levels, but their cost at present is still too
high....
In recent years, considerable attention has been focused on the application of
orthogonal expansions to system analysis, parameter identification, model reduction
and control system design. However, little research has been done in applying their
useful properties to Power System analysis and control. This research attempts to
make some inroads in...
Many systematic methods exist for mapping algorithms to processor arrays. The algorithm is usually specified as a set of recurrence equations, and the processor arrays are synthesized by finding timing and allocation functions which transform index points in the recurrences into points in a space-time domain. The problem of scheduling...
The parallelization and vectorization of Monte Carlo algorithms for modelling
charge transport in semiconductor devices are considered. The standard ensemble
Monte Carlo simulation of a three parabolic band model for GaAs is first
presented as partial verification of the simulation. The model includes scattering
due to acoustic, polar-optical and intervalley...
The propagation characteristics of a new coupled fin line structure, with
asymetrical, rectangular, top and bottom housings, is evaluated by using the modal
analysis technique. The boundary Green's function of the structure, relating the surface
currents to the electric fields is derived by using this technique. The propagation
characteristics, i.e....
Fully efficient systolic arrays for the solution of Toeplitz
matrices using Schur algorithm [1] have been obtained. By applying
clustering mapping method [2], the complexity of the algorithm is
0(n) and it requires n/2 processing elements as opposed to n
processing elements developed elsewhere [1].
The motivation of this thesis...
Mercury cadmium telluride is important in the detection
of electromagnetic radiation in the eight to twelve micron
atmospheric window for infrared imaging systems. High
resolution infrared imaging systems use either large (256x256
element to 1024x1024 element) staring arrays or much smaller
(1-6 element) scanned arrays in which the image is...
A study of deep levels of the emitter region of a
heterojunction bipolar transistor is investigated using deep
level transient spectroscopy (DLTS), deep level admittance
spectroscopy (DLAS), thermally stimulated capacitance
(TSCAP), and capacitance-voltage (C-V) profiling. The DX
center, with an activation energy of 0.45 eV, is the only
deep level...
With the advancement of technology, submicron CMOSonly process is available now for
Application Specific Integrated Circuits (ASICs). The high integration leads to the need for
high pin counts. However voltage supply and ground bounce due to many output drivers
switching at the same time is becoming a major problem. In...
Control oriented local area networks (COLANs) are being installed in factories at an increasing rate. Traditionally, process control has operated with a master scheduler (computer) monitoring a number of points in a control grid. As the complexity of today's process control needs grow, the need to process information locally increases....
The design and implementation of Switched-Current (SI) ladder filters is
described. SI filters require only a standard digital CMOS process and the power
supply voltage requirement is low. SI circuits also can be potentially operated at
higher frequencies than Switched-Capacitor (SC) filters due to the low-impedance
wideband nodes of the...
Relational database systems have successfully solved many
business data processing problems. The primary reason of this
success is that the relational data model provides a simple, yet
flexible view of data as tables. In studying VLSI/CAD data, we noticed
that they are often represented in formats similar to relational
tuples....
A new algorithm is proposed which provides a sub-optimum near-far resistant
pattern for correlation with a known signal in a spread-spectrum multiple access
environment with additive white gaussian noise (AWGN). Only the patterns and
respective delays of the K-1 interfering users are required. The technique does not
require the inversion...
A series of complex digital blocks have been designed and fabricated using the newly
developed current-mode differential CMOS logic family viz. the Folded Source-Coupled
Logic ( FSCL ). The main feature of this logic family is the low current spikes generated
during the switching transitions ( at least 2 orders...
In this thesis a numerical technique to model general microstrip asymmetric and multiple step discontinuities is presented. The method is based on a magnetic wall waveguide model that is assumed to be valid for describing the electromagnetic fields associated with the microstrip line and in the vicinity of microstrip discontinuities....
Present day data processing technology requires very high speed signal processing
and data conversion rates. Traditionally, these circuits have been implemented in silicon
MOS technology, whose high speed performance is limited, due to inherent material properties.
Though relatively immature compared to silicon technology, GaAs integrated circuit
technology appears to be...
Present day data processing technology requires very high speed signal processing and data conversion rates. One such application which requires high speed is switched capacitor circuits used in Sigma-Delta modulators. A major active component of switched capacitor circuits is the monolithic operational amplifier(opamp). Because of the relatively poor speed performance...
A computer model simulating the electrical activity of muscles of the upper
arm during elbow motion is presented. The output of the model is an
Electromyographic (EMG) signal. System identification is performed on the EMG
signals using autoregressive moving average (ARMA) modelling. The calculated
ARMA coefficients are then used as...
The low thermal conductivity of gallium arsenide compared to silicon
results in self-heating effects in GaAs MESFETs that limit the electrical
performance of such devices for high power applications. To date, analytical
thermal models of self heating in GaAs MESFETs are based on the assumption
of a uniformly heated channel....
This thesis describes the design of a RISC architecture
for high speed data acquisition. The structure of existing
data acquisition systems is first examined. An instruction
set is created to allow the data acquisition system to serve
a wide variety of applications. The architecture is designed
to allow the execution...
Clock-feedthrough effects, channel-length modulation and device mismatch are
the main causes of the inaccuracy of Switched-Current (SI) circuits. In this paper, these
non-ideal effects are analyzed. A high-performance current mirror, namely regulated
cascode current mirror, which eliminates drain voltage variation problem is introduced.
By using this current mirror as a...
The semiconductor gallium arsenide (GaAs) has many potential
advantages over the more widely used semiconductor silicon (Si).
These include higher low field mobility, semi-insulating substrates,
a direct band-gap, and greater radiation hardness. All these
advantages offer distinct opportunities for implementation of new
circuit functions or extension of the operating conditions...
The motivation of this research is to study different cache designs for on-chip
caches that improve processor performance and at the same time
minimize the degradation to system performance caused by an increase in
the processor memory traffic. As VLSI technology advances we can have
bigger and more complex on-chip...
The loads on the electrical systems of automobiles are projected
to increase significantly in the near future. This will result in a
requirement for improved efficiency over the present-day car
alternators. An alternative scheme proposed at Oregon State
University employs a Brushless Doubly-Fed Machine (BDFM) as an
alternator.
This thesis...
In this thesis the concept of inhomogeneous
dielectrics is demonstrated for various optical coating
applications. Compositionally-varying silicon oxynitride
(SiON) dielectric layers, with the refractive index
varying as a function of position, are grown by computer-controlled
plasma-enhanced chemical vapor deposition
(PECVD) using silane, nitrogen, and nitrous oxide reactant
gases. Compositionally graded...
This thesis describes the analysis and comparison of Folded Source-Coupled
Logic (FSCL) with standard static CMOS, cascode voltage-switch logic and differential
split-level logic gates. The advantages of FSCL are low switching noise and
high operating speed. The effect of voltage and device scaling on these topologies is
evaluated in terms...
A mathematical model of Limiting Dilution Analysis for two limiting
parameters is presented and investigated. Limiting Dilution Analysis is a microbiological
cell assay developed for immunological application. In the given
case we deal with the interaction between B lymphocytes, macrophage derived
factor and T-independent antigens. The state of the art...
The dataflow model of computation differs from the traditional control-flow
model of computation in that it does not utilize a program counter to sequence
instructions in a program. Instead, the execution of instructions is based solely on the
availability of their operands. Thus, an instruction is executed in a dataflow...
Long bridges tend to develop large deformations under the
action of intense dynamical loads such as wind or earthquakes.
Unless these deformations are controlled in some fashion, the
structure might suffer damage or even collapse. One possible
solution to this problem is to apply external forces to the
bridge through...
Delta-Sigma Modulator-based Analog-to-Digital converter design is an active area of research. New topologies require extensive simulations to verify their performance. A series of improvements were made to an existing circuit simulation package in order to speed the simulation process for the designer. Various examples of these improvements are presented in...
The purpose of this study is to develop experimental techniques to
characterize typical interconnect discontinuities, including bends, steps, T
junctions, vias and pads, which are the most commonly encountered
interconnections in high speed digital integrated circuits, hybrid and
monolithic microwave circuits and electronic packages. The time domain
reflection response of...
Amateur Packet Radio Networking presently uses the NET/ROM
protocol to establish the network. NET/ROM is considered to be
insufficient to support the expected growth of the network. This
research work proposes to use the TCP/IP protocol suite instead to
build the network. A comparison between features of both protocols
supports...