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...
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,...
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...
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...
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...
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...
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...
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...
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,...
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...
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...
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...
In wireless sensor network applications, low-power operation of the wireless receiver is critical. To address this need an ultra-low power Binary Frequency Shift Keying (BFSK) receiver using the super-regenerative architecture is developed.
A prototype receiver is built and tested for operation in the 900 MHz ISM band. Lab measurements show...
Recent advances in wireless technologies have helped the proliferation of wireless devices, ranging from hand-held devices such as cellular phones to more powerful mobile computing platforms as such laptops [1]. Along with that, the end users’
applications running on these devices, ranging from text message to multimedia applications such as...
Advances in process technologies have led to the development of low-power high speed digital signal processing blocks that occupy small areas. These advances are critical in the development of portable electronic devices with small feature size and long battery life. However, the design of analog and mixed-signal
building blocks, especially...
Short-range wireless communications continually attract interest from both industry and academia, and it is changing our life in every aspect in the last decade. The design of wireless transceivers is the bottleneck for variety applications, due to RF modeling inaccuracy, stringent FCC regulations over the transmitted power spectrum, interference, multi-path...
As the number of mobile devices accessing large-scale WLANs such as campus
and metropolitan area networks increases, the need for load balancing among the
cells becomes crucial. In addition, the network must also support some minimum
handoff tolerance defined by an application.
A number of load balancing techniques have been...
The decrease of switching times accompanied by the corresponding increase of
clock speeds and data rates, contributes to improve the overall system
computational performance. At the same time, they also affect wireless
communications due to an increment in the emissions of electromagnetic
radiation on the radio bands.
In this dissertation...
In networked control systems (NCS) information or packets usually flow from a
sensor or a set of sensors to a remotely located controller. Then the controller
processes the received information and sends a series of control commands to the
actuators through a communication network which could be either wireless or...
Two aspects of ADC system performance are addressed in this work. First, the combination of the ADC and its associated reference are co-designed for an energy constrained remote sensing system. Second, sampling linearity is mathematically analyzed as a function of frequency to provide enhanced understanding into an ADC's requisite sampling...
High speed serial links are critical components for addressing the growing demand for I/O bandwidth in next-generation computing applications, such as many-core systems, backplane and optical data communications. Due to continued process scaling and circuit innovations, today's CMOS serial link transceivers can achieve tens of Gb/s per pin. However, most...
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....
In some practical systems, most of the errors are of 1 → 0 type and 0 → 1
errors occur very rarely. In this thesis, first, the capacity of the asymmetric
channel is derived. The capacity of the binary symmetric channel (BSC) and the
Z-channel can be derived from this...
The meteoric rise and prevalent usage of wireless networking technologies for mobile
communication applications have captured the attention of media and imagination of
public in the recent decade. One such proliferation is experienced in Wireless Sensor
Networks (WSNs), where multimedia enabled elements are fused with integrated
sensors to empower tightly...
This dissertation presents a low-power high-resolution delta-sigma ADC. Two new architectural design techniques are proposed to reduce the power dissipation of the ADC. Compared to the conventional active adder, the direct charge transfer (DCT) adder greatly saves power by keeping the feedback factor of the active adder unity. However, the...
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,...
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...
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 increased use of mobile wireless devices that we have recently been witnessing, such as smartphones, tablets, e-readers, and WiFi enabled devices in general, is driving an unprecedented increase in the amount of data traffic. This fast market adoption of the wireless technology along with the tremendous success of multimedia...
In an industrial and consumer electronic marketplace that is increasingly demanding greater real-world interactivity in portable and distributed devices, analog to digital converter efficiency and performance is being carefully examined. The successive approximation (SAR) analog to digital converter (ADC) architecture has become popular for its high efficiency at mid-speed and...
Frequency synthesizers are critical components of all communication systems. This thesis considers the issue of undesirable frequency spurs of a relatively recent type of frequency synthesis architecture called digital-to-time conversion (DTC). The DTC-based frequency synthesis architecture has important performance benefits over older frequency synthesizers, such as fast frequency switching, large...
Ultra-high-speed (>10GS/s), medium-resolution (5~6bit), low-power (<50mW) analog-to-digital converter can find it application in the areas of digital oscilloscopes and next-generation serial link receivers. There are several challenges to enable a successful design, however. First, the time-interleaved architecture is required in order to achieve over 10GS/s sampling rate, with the trade-off...
For the past half century, CMOS process scaling has followed Moore's law, approximately doubling transistor density every 18 months. While locally routed wires have generally scaled with transistor size, longer wires have scaled at a slower rate and in some cases have grown larger as chip size and complexity have...
Radioxenon detection is a technique used to monitor nuclear explosion and verify the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Because of an ultra-low concentration of radioxenon at radioxenon monitoring stations, radioxenon detection systems must have high sensitivity. This sensitivity is measured in terms of detector's minimum detectable concentration (MDC). It is required...
Routing from a single source node to multiple destination nodes using node disjoint paths (NDP) has many important applications in parallel systems. For example, if a source node wants to send distinct messages to distinct destination nodes, then the one-to-many NDP routing is useful.
Unlike parallel systems with shared-memory, each...
A procedure for automating the design and layout of analog-to-digital converters (ADCs) is presented. This procedure makes use of the existing synthesis and place-and-route tools that are common in digital circuit design. A method for adding rudimentary analog cells to the standard library is described, allowing the designer to synthesize...
Data converters are essential interface circuits between the analog world that people live in and the digital processors that people live with. Linearity, which often is a tradeoff against other performance criteria, is one of the major performance demands from applications for both analog-to-digital converts (ADC) and digital-to-analog converters (DAC)....
Wireless High Definition Video Transmission (WHDVT) over 802.11-based networks enjoys widespread deployment among today's multimedia solutions. Examples include Intel® Wireless Display and Apple Airplay®, to name a few. In these systems, peer-to-peer networks are established over which H.264-encoded video is transported wirelessly to be decoded and played back at the...
The complexity of designing and testing today's system on chip (SOC) is increasing due to greater integrated circuit (IC) density and higher IO and memory frequencies. SOCs for the mobile phone and tablet market have the unique challenge of short product development windows, at times less than six months, and...
The design of mobile wireless devices has always focused on reducing power, area, and cost. This dissertation proposes two techniques that are leveraged to save power and area and therefore cost. The first techniques reduces the noise in the receiver and results in a relaxed power requirement. The second technique...
Detection of xenon radioisotopes (radioxenons) has proven to be an important method for detecting nuclear explosions and is particularly well suited for detecting undeclared underground testing. The radioxenon isotopes ¹³¹mXe (t₁/₂ = 11.934 d), ¹³³mXe (t₁/₂ = 2.19 d), ¹³³Xe (t₁/₂ = 5.243 d) and ¹³⁵Xe (t₁/₂ = 9.14 h)...
This dissertation focuses on the development of ultra-compact optical devices for free-space modulation. We propose a surface-normal modulator using metallic photonic crystals for free-space optical interconnects. The active control of light intensity is achieved by engineering the Fano resonances in metallic photonic crystals. Both thermo-optic modulation and electro-optic modulation of...
Recent sensor System-on-Chips (SoC) have enabled significant advances in energy-efficiency by incorporating various micro-powered building blocks. Unfortunately, most of these sensor systems do not address the high power cost associated with data storage and transmission, which in some cases vastly exceeds the power consumed by the rest of the SoC....
Triangulateration uses geometric distance to estimate the location of user by employing techniques like received signal strength (RSS), time-of-arrival (TOA), time-difference-of-arrival (TDOA) and image processing.
Radio frequency (RF) signal positioning using TOA or TDOA techniques generally requires timing synchronization of the anchors and/or the anchors and targets. If the desired...
The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosion tests for military or civilian purposes. The International Monitoring System (IMS) was established to verify compliance with the treaty. It consists of several monitoring stations that detect: seismic activities, hydrocoustic activities, infrasound waves, and radionuclide particles and noble gases. Radioxenon detection...
Analog-to-digital converters are essential components to the portable devices that we are using today. Wireless sensors, body implanted devices, communication devices and so forth require low power ADCs. Therefore achieving higher resolution and bandwidth with lower power consumption is targeted in ADCs design. In this work power efficient ADCs for...