With increasing operating frequencies in CMOS RF/microwave integrated circuits,
the performance of on-chip interconnects is becoming significantly affected by the lossy
substrate. It is the purpose of the first part of this thesis to develop a rigorous field
theoretic analysis approach for efficient characterization of single and multiple coupled
interconnects...
During the last few years we have seen formidable advances in digital and mobile
communication technologies such as cordless and cellular telephones, personal
communication systems, Internet connection expansion, etc. The vast majority
of digital information used in all these applications is stored and also processed
within a computer system, and...
In recent years, the elliptic curve cryptosystems (ECC) have received attention
due to their increased security with smaller key size which brings the advantage of less
storage area and less bandwidth. Elliptic curve cryptography provides a methodology
for obtaining high-speed, efficient, and scalable implementations of network security
protocols. In addition...
As the information-processing and telecommunications revolutions now underway will continue to change our life styles in the rest of the 21st century, our personal and economic lives rely more and more on our ability to transact over the electronic medium in a secure way. The privacy, authenticity, and integrity of...
Power quality has become an important concern to both electric utilities and
end users due to the increased use of non-linear loads in modem power systems
over the past decade. Nonlinear loads inject harmonics into the power system and
thus may lead to poor power quality and lower power factor....
Current superscalar microprocessors' performance depends on its frequency and the
number of useful instructions that can be processed per cycle (IPC). Higher frequency
is achieved with process advancement, new circuit techniques, and microarchitectural
improvement. Number of instructions processed per cycle depends mainly on
microarchitecture techniques that exploit parallelism both spatially...
The objective of the research presented in this thesis is to develop, implement, and demonstrate the utility of an n-sheet, state-space alternating-current thin-film electroluminescent (ACTFEL) device model. In this model, the phosphor layer is discretized into n + 1 layers, with band-to-band impact ionization, space charge creation/ annihilation, and luminescent...
In this dissertation, a new Δ∑ A/D converter is presented that is ideally suited for communication applications. It is based on a single-loop single-stage structure, which can realize a high maximum out-of-band quantization noise gain while maintaining stable operation and thus achieve 14-bit resolution at 8 times oversampling. A fifth-order...
In this thesis, we study the Karatsuba-Ofman Algorithm (KOA), which is a recursive multi-precision multiplication method, and improve it for certain special applications. This thesis is in two parts. In the first part, we derive an efficient algorithm from the KOA to multiply the operands having a precision of 2[superscript...
We describe novel methods for obtaining fast software implementations of the arithmetic operations in the finite field GF(p) and GF(p[superscript k]). In GF(p) we realize an extensive speedup in modular addition and subtraction routines and some small speedup in the modular multiplication routine with an arbitrary prime modulus p which...
The most accurate method for performing analog signal processing in MOS (metal-oxide-semiconductor) integrated circuits is through the use of switched-capacitor circuits. A switched-capacitor circuit operates as a discrete-time signal processor. These circuits have been used in a variety of applications, such as filters, gain stages, voltage-controlled oscillators, and modulators. A...
Concurrent error detection (CED) is the detection of errors or faults in a circuit or data path concurrent with normal operation of that circuit. The general approach for CED is to calculate a check symbol for the inputs to the circuit under operation, predict the check symbol that will result...
The computation of the inverse of a number in finite fields, namely Galois Fields GF(p) or GF(2ⁿ), is one of the most complex arithmetic operations in cryptographic applications. In this work, we investigate the GF(p) inversion and present several phases in the design of efficient hardware implementations to compute the...
While the performance gap between microprocessors and main memory is ever increasing each year, cache memory has been a bridge to alleviate this discrepancy. In this thesis proposal, we introduce three techniques to tolerate this processor and memory speed imbalance. First, we propose the bloom filter scheme to identify which...
Continuous process scale-down and emerging markets for low-power/low-voltage mobile systems call for low-voltage analog integrated circuits. Switched-capacitor circuits are the building blocks for analog signal processing and will encounter severe overdrive problems when operating at low-voltage conditions. There are several well-known techniques to bypass the problem. These approaches include: (1)...
This dissertation investigates diverse techniques to support multithreading in modern high performance processors. The mechanisms studied expand the architecture of a high performance superscalar processor to control efficiently the interaction between software-controlled and hardware-controlled multithreading. Additionally, dynamic speculative mechanisms are proposed to exploit thread-level-parallelism (TLP) and instruction-level-parallelism (ILP) on a...
Advancements in power electronics to higher power levels and faster switching times allow new machine and systems designs, but also create higher stresses on electric machinery insulation. High performance, pulse-width modulated (PWM) inverters are now available for medium voltage drive systems, and are being considered by the U.S. Navy as...
The aim of this dissertation is to develop non-traditional approaches to alternating-current thin-film electroluminescent (ACTFEL) device fabrication. ACTFEL technology suffers from a lack of adequately bright and efficient primary-color phosphors and cannot presently compete in the low-cost display market. Therefore the research presented in this dissertation focuses on an exploration...
The objective of this dissertation is to introduce low-cost processing methods for the fabrication of ZnO transparent thin-film transistors (TTFTs). A novel method for depositing ZnO body layers via spin-coating of a zinc nitrate-based spin solution is presented. The processing conditions of spin-coated ZnO are optimized to produce continuous and...
With the development of high performance power electronic and semiconductor technologies, Adjustable Speed Drive (ASD) systems are increasingly applied in residential, commercial and industrial applications. Due to the advantages at higher power ratings, the three-level Neutral-Point-Clamped (NPC) Voltage Source Inverter (VSI) is being employed in industrial and traction applications, static...
Pipelined analog to digital converters (ADCs) are very important building blocks in many electronic systems such as high quality video systems, high performance digital communication systems and high speed data acquisition systems. The rapid development of these applications is driving the design of pipeline ADCs towards higher speed, higher dynamic...
Advanced low power devices promote the development of micro power generators (MPGs) to replace the batteries to power them. Due to the trend in decreasing integrated circuit (IC) supply voltages, power supply designers are facing more and more serious challenges. The objective of this research is to design a power...
This thesis proposes a novel fully digital technique for the estimation and correction of the DAC error in multi-bit delta sigma ADCs. The structure of the DAC error is indicated through a simple model for unit-element based DACs. The impact of the DAC error on the performance of ADC is...
In the first part of this dissertation, low frequency l/f or flicker noise in the frequency range of Hz to kHz has been identified and demonstrated to be described by temperature fluctuations in heat conduction in bipolar transistors operated at higher power densities. This noise phenomenon is not described by...
The focus of this work is on the steady-state analysis of RE circuits using a coupled device and circuit simulator. Efficient coupling algorithms for both the time-domain shooting method and the frequency-domain harmonic balance method have been developed. A modified Newton shooting method considerably improves the efficiency and reliability of...
Systems biology is becoming increasingly important for the study of living organisms. It focuses on the mathematical understanding of biological systems. Cells, the basic units of all living creatures, are biological systems of major interest. Considerable work is being done towards modeling cells as mathematical systems. At the same time,...
This dissertation investigates the use of a hardware mechanism called Eager Data Transfer (EDT) for achieving the reduction of communication latency for user-level network protocol. To reach the goal, the dissertation addresses the following research issues. First, the development of a communication system performance evaluation tool called Linux/SimOS is presented....
Multi-stage delta-sigma (ΔΣ) architectures, commonly known as MASH, are the preferred choice for analog-to-digital converters (ADCs) used in broadband communication applications, where high-resolution (above 14 bits) and high-bandwidth (several MHz) performances are required. Current state-of-the-art designs are capable of as much as 5-MS/s output data rates with 90-dB SNR. However,...
The spread of the internet and communications techniques increases the necessity
for security in applications that involves sharing or exchange of secret or private infor-
mation. Public-key cryptography is widely used in establishing secure communication
channels between the users on the Internet, for E-commerce transactions, and in net-
work security...
The asymmetric nature of bit errors in several practical applications provides grounds for efficient error control techniques. The Z-channel model and special classes of codes like asymmetric error detection codes and t-asymmetric error correcting/d-asymmetric error detecting codes can be successfully used in ARQ protocols for feedback error control enhancement. This...
In this thesis, novel solutions are proposed for key management issues in mobile ad hoc networks. Presented Hierarchical Binary Tree (HBT) based model is distributed, self-organizing, scalable and does not employ online key distribution authority or group manager. Two different group authentication and group key establishment protocols are proposed for...
In many areas of engineering and applied mathematics, spectral methods provide very powerful tools for solving and analyzing problems. For instance, large to extremely large sizes of numbers can efficiently be multiplied by using discrete Fourier transform and convolution property. Such computations are needed when computing π to millions of...
Preventative methods for software reverse engineering have been given greater attention in recent times due to the increase in computational resources and tools available to the public. The inherent security provided by encoding source into machine code (executable form) can no longer be assumed, given the availability of effective automated...
The focus of this work is on developing algorithms for frequency domain steady-state analysis of oscillators. Convergence problems associated with the frequency domain harmonic balance simulation of oscillators have been examined. Globally convergent homotopy methods have been combined with the harmonic balance method for robust high-Q oscillator simulation. Various homotopy...
Spiral inductors are a key component of mixed-signal and analog integrated circuits (IC's). Such circuits are often fabricated using silicon-based technology, owing to the inherent low-cost and high volume production aspects. However, semiconducting substrate materials such as silicon can have adverse effects on spiral inductor performance due to the lossy...
Ferrites have been used for various high frequency applications as bulk
materials. These applications, however, are limited to large dimension devices. In
this thesis, thin film ferrites were deposited from a low temperature solution-based
deposition process that is suitable for micro-scale high frequency applications. The
low temperature nature of this...
With the ever-increasing demand for portable devices used in applications
such as wireless communication, mobile computing, consumer electronics, etc.,
the scaling of the CMOS process to deep submicron dimensions becomes more
important to achieve low-cost, low-power and high-performance digital systems.
However, this downscaling also requires similar shrinking of the supply...
Digital-to-analog converters (DACs) suffer from static and dynamic nonlinearity problems, which degrade their accuracy and performance. Mismatch errors in the analog components restrict the maximum achievable linearity.
This thesis presents various techniques for correcting these errors. It describes a correction process for the nonlinear behavior of DACs, on three different...
Commonly proposed ocean wave energy converters (OWEC) use inefficient and maintenance demanding intermediate hydraulic and pneumatic systems. We propose a novel rotary direct-drive OWEC that eliminates these intermediate stages. The new device employs a contactless force transmission system (CFTS) comprising a “piston” and a “cylinder” and a ball screw to...
Designing spectral efficient, high-speed wireless links that offer high quality-
of-service and range capability has been a critical research and engineering challenge. In this thesis, we mainly address the complexity and performance issues of
channel estimation and data detection in multiple-input multiple-output (MIMO)
orthogonal frequency division multiplexing (OFDM) systems over...
Traditionally linear actuator applications are addressed by the use of hydraulic systems. The high maintenance cost and poor reliability will always be the most critical problem in the real applications. Benefited from both the high mechanical advantage of the roll screw and the simple structure of the switched reluctance motor,...
In recent years, there has been growing interest in both industry and academia to use continuous-time (CT) Δ-Σ A/D converters for wideband wireless and wireline communication applications.
So far no reported CT Δ-Σ A/D modulator achieves 14-bit or higher dynamic range (DR) with more than 2MHz signal bandwidth (equivalently 4MS/s)....
The demand for portable electronic systems and the continued
down-scaling of device dimensions resulted in rapid improvement in
the performance of integrated systems. Several low-voltage design
techniques have been proposed to operate analog circuits with sub-1V
supply. However, these techniques require higher power consumption
to achieve large dynamic range while...
In modern on-chip memories, an increasing demand for higher performance, lower power, reduced area, and improved robustness creates a rising need for advanced microarchitecture and circuit design techniques. Particularly in large-signal multi-ported register files, these advanced design techniques include: (i) multi-banked arrays, (ii) multi-frequency arrays, (iii) multi-bit width gating, (iv)...
Digital-to-analog converters (DACs) with wide dynamic range and high
linearity are required for high-end audio applications. A multi-bit delta sigma
audio DAC, using a novel gain-correction technique, is described in this thesis. For
widely varying on-chip RC time constant, the DAC gain can be accurately
controlled by the correction circuitry....
Achieving sharpened (enhanced detail) features of a multi-dimensional data source using the linear prediction (LP) bandwidth extrapolation (BWE) technique in the transform domain is the main objective of this research. The evolution of sensor technology has provided acquisition scenarios in which the data format is inherently multi-dimensional, including hyperspectral imaging...
Ultra-wideband (UWB) communication has emerged as a very promising
technology for short-range wireless applications, including
high-speed multimedia transmissions and sensor networks. UWB
system designs involve many different aspects covering analog and
digital processing, channel estimation and modeling, and
modulation and demodulation. Although UWB still faces many
challenges, significant progress has...
Multiple-input multiple-output (MIMO) antenna technology is promising
for high-speed wireless communications without increasing the transmission band-
width. Space time coding (STC) is a scheme that employs multiple antennas to
increase transmission rate or to improve transmission quality. STC is used widely
in mobile cellular networks, wireless local area networks (WLAN)...
Authentication protocols play important roles in network security. A variety of authentication protocols ranging from complex public-key cryptosystems to simple password-based authentication schemes have been proposed. However, currently there is no fully secure authentication scheme that can resist all known attacks. When a user authentication is performed over an insecure...
Scaling of CMOS technology has progressed relentlessly for the past several
decades. In order for this unprecedented scaling to benefit the performance of
large digital systems, the communication bandwidth between integrated circuits
(ICs) must scale accordingly. However, interconnect technology does not scale as
aggressively, making communication between chips the major...
Orthogonal frequency division multiplexing (OFDM), which has been very attractive for future high rate wireless communications, is very robust to channel multipath fading effect while providing high transmission data rate with high spectral efficiency.
Multiple antennas can be combined with OFDM to increase diversity gain and to improve spectral efficiency...
As the functionality of digital chips continues to increase dramatically, chip- to-chip communication bandwidths must scale accordingly to avoid constraining the overall system performance. Therefore, high speed transceiver design has be- come an important research topic. In particular, the performance of the circuits that are responsible for timing accuracy are...
This dissertation presents a dual-path 2-0 MASH (Multi-stAge-noise -SHaping) ADC with two verified digital corrections of DAC mismatch error and quantization noise leakage. By using these two techniques, the requirements for the analog circuits are greatly relaxed. The dual-path structure generates two outputs, one only composed of conversion errors, the...
Cryptographic devices leak timing and power consumption information that is easily measurable, radiation of various levels, and more. Such devices also have additional inputs, other than plaintext and keys, like voltage, which can be modified to force the device to produce certain faulty outputs that can be used to reveal...
A digital implementation of a PLL has several advantages compared to its
analog counterpart. These include easy scalability with process shrink, elimination
of the noise susceptible analog control for a voltage controlled oscillator (VCO) and
the inherent noise immunity of digital circuits. Several recent digital PLL (DPLL)
implementations have achieved...
The continued scaling of deep-submicron CMOS technology enables low-voltage high-frequency phase-locked loops (PLLs) to be fully integrated in complex mixed-signal systems. However, fluctuations due to the manufacturing process and variations in
environmental conditions, such as supply voltage and temperature, are also significantly increased. As a result, the performance of PLLs...
With the growing demand for portable/consumer electronics, such as digital
audio/video (AV), the downscaling of device dimensions, which enables the
integration of an increasing number of transistors in a single chip, is mandatory.
This trend also continuously pushes the power supply voltage down to reduce the
power consumption and improve...
In this thesis, maximum likelihood Doppler frequency estimation and phase noise suppression algorithms for Orthogonal Frequency Division Multiplexing (OFDM) systems are presented. A novel handover decision algorithm for wireless systems, called predictive base station switching (PBSS), is also introduced.
The maximum Doppler Frequency is the ratio of the speed of...
Delta-Sigma (ΔΣ) analog-to-digital converters (ADCs) are widely used in wireless transceivers. Recently, continuous-time (CT) ΔΣ ADCs gain growing interest in wireless applications for their lower power consumption and wider input bandwidth as compared with the discrete-time (DT) counterparts.
In this thesis, a wideband low-power CT ΔΣ modulator for next generation...
The main contributions of this thesis are the development and
application of four computationally efficient solutions for
least-squares-based (LS-based) minimum variance spectral estimation
(MVSE). They are: (1) fast computational solution for the 1-D
covariance LS-based MVSE, (2) fast computational solution for the
1-D modified covariance LS-based MVSE, (3) fast computational...
The integration of renewable energy sources and the associated power electronics to notebook power and thermal management systems was investigated in this work. Both thermoelectric (TE) and photovoltaic (PV) energy extraction techniques were explored with the goal of achieving best sustainability. Semi-realistic usage assumptions were taken into account to evaluate...
The aim of this dissertation is to develop oxide semiconductors by radio-frequency
sputtering for thin-film transistor (TFT) applications. A variety of oxide semiconductors
are used as the TFT channel layer, including indium gallium oxide (IGO), zinc tin
oxide (ZTO), and indium gallium zinc oxide (IGZO). The variety of materials used...
Low-Density Parity-check (LDPC) codes have attracted considerable attention due to their capacity approaching performance over AWGN channel and highly parallelizable decoding schemes. They have been considered in a variety of industry standards for the next generation communication systems. In general, LDPC codes achieve outstanding performance with large codeword lengths (e.g.,...
The problem of locating a signal source, or an emitter, has many civilian and military applications, such as communication regulations enforcement, military reconnaissance, and search-and-rescue operations. Many of the most widely used emitter location methods rely on the accurate and robust estimation of the differential time delay,
or time-difference-of-arrival (TDOA),...
Multiple-input multiple-output (MIMO) communication systems have recently been considered as one of the most significant technology breakthroughs for modern wireless communications, due to the higher spectral efficiency and improved link reliability. The sphere decoding algorithm (SDA) has been widely used for maximum likelihood (ML) detection in MIMO systems. It is...
Although the digital revolution can realize many of past analog components in the digital forms, our world is surrounded with analog signals such as voice, temperature, etc. The bridge between these two worlds is one of key performance limitations among overall systems and it includes analog filters and data converters....
Harvesting energy from the environment for powering micro-power devices have been increasing in popularity. These types of devices can be used in embedded applications or in sensor networks where battery replacement is impractical. In this dissertation, different methods of energy harvesting from the environment are explored as alternative sources of...
Enabled by continued device scaling in CMOS technology, more and more functions that were previously realized in separate chips are getting integrated on a single chip nowadays. Integration on silicon has opened the door to new portable wireless applications, and initiated a widespread use of these devices in our common...
This research work focuses on the mechanism of 1/f noise in GaAs
resistors on semi-insulating substrates and 1/f noise due to temperature
fluctuations in heat conduction in resistors, diodes, and bipolar transistors. The
goal of this research is to generate accurate models to explain physical origin of 1/f
noise in...
Wireless Networks have been widely adopted into a major part of today's network infrastructure. They have become a popular technology to not only expand the coverage of wired networks but also to interconnect a large wireless network, i.e., wireless mesh networks. As they allow more flexible communication than traditional wired-networks...
Low noise oscillators are universally needed in digital systems for clock generation and synchronization, and in radio-frequency communication front-ends for frequency up- and down-conversion. Noise in oscillators results in timing jitter, and limits the clock frequency of digital systems. In radio-frequency communication systems, phase noise in oscillators lowers the signal-to-noise...
The exponential rate of advances in modern communication devices in the last several years have brought us higher levels of functionality and performance as well as reductions in physical size and power consumption. To continue this rate of advancement, next generation systems require wider bandwidth and higher resolution ADCs. Additionally,...
A class of inorganic thin-film transistor (TFT) semiconductor materials has emerged involving oxides composed of post-transitional cations with (n-1)d¹⁰ns⁰ (n≥4) electronic configurations. This thesis is devoted to the pursuit of topics involving the development of these materials for TFT applications: Deposition of zinc oxide and zinc tin oxide semiconductor
layers...
Analog-to-digital converters (ADCs) convert analog
continuous time signals into discrete time, digital format. One
precondition that must be met for conventional nyquist rate ADCs is
that the input signal must be suitably band-limited to an input
bandwidth less than the nyquist frequency. This mandates expensive
anti-alias filters which contribute to...
This thesis presents methods to reduce the effects of finite opamp DC gain, output voltage swing limitations in opamps, and component mismatches. The primary contribution of this thesis is a new switched-capacitor method named correlated level shifting (CLS). CLS enables true rail-to-rail operation by storing an estimate of the desired...
Real world is analog but the processing of signals can best be done in digital domain. So the need for Analog to Digital Converters(ADCs) is ever rising as more and more applications set in. With the advent of mobile technology, power in electronic equipment is being driven down to get...
Dynamic CMOS circuits are commonly used in high-performance memory arrays to implement wide-NOR logic functions for their read and search operations. This is because dynamic circuits have significantly higher speed and lower area compared to static circuits for performing similar operations. Register File (RF) arrays are located at the top...
Automated recognition of object categories in images is a critical step for many real-world computer vision applications. Interest region detectors and region descriptors have been widely employed to tackle the variability of objects in pose, scale, lighting, texture, color, and so on. Different types of object recognition problems usually require...
Evolution of the mobile communication standards and proliferation of hand-held devices mandate stringent Analog-to-Digital Converter (ADC) specifications. Among various ADCs, a ∆Σ ADC is best known as a power-efficient ADC when more than 12b is required. However, a conventional discrete-time (DT) ∆Σ Modulator (∆ΣM) is inadequate for low-power wideband applications...
General purpose computer systems have seen increased performance potential through the parallel processing capabilities of multicore processors. Yet this potential performance can only be attained through parallel applications, thus forcing software developers to rethink how everyday applications are designed. The most readily form of Thread Level Parallelism (TLP) within any...
Until a few years ago, wireless-capable laptops were considered novelties by many. It is now hard to find a laptop or a hand-held computing device that is not wireless-ready. As wireless devices are becoming commodities, they have also become an indispensable part of the modern society. Not surprisingly, research in...
It is well known that multipath effects cause inter-symbol interference (ISI) for high-speed signaling and ultimately limit the achievable data rate at any frequency band. In this thesis, we study several different methods to tackle this issue and provide solutions for establishing efficient wireless links that can provide several Gbps...
Delta-Sigma (ΔΣ) analog-to-digital converters (ADCs) are traditionally used in high quality audio systems, instrumentation and measurement (I&M) and biomedical devices. With the continued downscaling of CMOS technology, they are becoming popular in wideband applications such as wireless and wired communication systems,high-definition television and radar systems. There are two general realizations...
A duty-cycle controlled switched resistor is a tunable resistive element that uses pulse width modulation as the method of tuning. This thesis will describe the operation of switched resistors and propose several circuit architectures that are well suited to the use of switched resistors. These architectures include filters, mixers, and...