Electrical and Electronics Commons^™

Dynamically Biased Radio Frequency Power Amplifier, Tom Twomey

Theses

With the current trend in mobile communications towards more complex modulation schemes to enhance spectral efficiency, the design of RF power amplifiers is the subject of considerable interest and research. The newer more spectrally efficient modulation schemes require a much higher level of linearity due to the non-constant level of their signal envelope. A variable envelope signal would in non-linear amplifiers lead to unacceptable levels of distortion. Linear amplifiers solve this problem at the cost of significant loss of efficiency. With the evolution towards more spectrally efficient modulation schemes, the trade off between linearity and power efficiency has become more …

Automated Distribution And Management Of Software And Hardware Configurations For Heterogeneous Wireless Devices, Grainne Foley

Theses

The continuing evolution of wireless networks and services has increased the complexity and diversity of wireless networks and devices, placing significant emphasis on the need for flexible device configuration management. Widely varying wireless technologies currently operate independently worldwide, making global wireless network access for the mobile user confusing and unwieldy. New technologies, network access methodologies and improved services further obscure the evolving environment. The focus of effort for this thesis is the development of a system to automate the distribution and management of software and hardware configurations that enable different levels of wireless device reconfiguration. The scope of investigation will …

Performance Evaluation Of Sip Based Services In Umts, Maria Isabel Pous Fenollar

Theses

With ever increasing penetration of IP technologies and the tremendous growth in wireless data traffic, the wireless industry is evolving the mobile core networks towards IP technology. The 3rd Generation Partnership Project (3GPP) is specifying an IP Multimedia Core Network Sub-System (IMS) in UMTS Release 5 and Release 6, which is adjunct to the UMTS GPRS core network. This IP-based network will allow mobile operators to provide commonly used Internet applications to wireless user. The UMTS IMS uses the Internet Engineering Task Force (IETF) defined text based Session Initiation Protocol (SIP), to control a wide range of anticipated IP-based services …

Multiple Model Control With Intelligent Switching To Ensure Robustness To Process Variations., Peter Cunningham

Theses

One of the most popular approaches for dealing with process that undergo large variations with time, of late, is the multiple model approach. This method has considerable intuitive appeal and has received widespread dissemination in academia. Numerous successful simulations have been reported although few real-time results have been published. The principal contribution of this thesis is the application of the multiple model control scheme in real-time.

A number of practical concepts that enable the use of multiple model control in real-time are discussed. Many of these issues arose when the multiple model control scheme was applied to a laboratory scale …

Hot Carrier Reliability Of Lateral Dmos Transistors In Power Process Applications, Vicky O'Donovan

Theses

The purpose of this study is to investigate and validate the mechanism of hot carrier degradation of the LDMOS device. The LDMOS device is a new technology to Analog Devices, and a relatively new topic to the semiconductor industry, evident from the limited published research in the field. A prerequisite for device release on a product in the market place, is comprehensive hot carrier reliability testing, as hot carrier degradation has evolved as one of the foremost concerns in submicron devices. Both the high voltage and the structural difference of the LDMOS device, from standard MOSFET device, pose a hot …

Adaptive Baseband Predistortion For Rf Power Amplifier Linearization., Laura Faus-Ferrer

Theses

In order to make use of spectrally efficient linear modulation methods for mobile communications, it is necessary to linearise the underlying RF power amplifier (PA). A number of techniques for linearizing a PA have been studied, focusing on the Adaptive Baseband Predistortion. The work is centred on the research concentrates on the analysis of different algorithms, their simulation using MatLab, and implementation of a predistorter as a subsystem of a prototype Cartesian based transmitter.

The thesis describes the typical architecture of a transceiver with an emphasis on the nonlinear analysis. Cavers’ algorithm has been examined in terms of its computational …

Modern Control Techniques For Induction Machines In High-Performance Adjustable-Speed Drives, Pat Cronin

Theses

Induction Motors (IM’s) are increasingly being considered for and used in high-performance motor drive (HPMD) systems. Their application has only gained acceptance since the 1970’s with the advent of vector control, microprocessors and improvements in power converter technology. D.C. motors were traditionally the preferred choice in HPMD systems. The main reasons for IM acceptance in HPMD systems are ruggedness, durability, low maintenance, cost, and small size by comparison with D.C. motors.

Alternating current asynchronous motors of the IM type are considered to be the universal workhorses of the manufacturing industry. It has been estimated that they are used in seventy …

Design For Signal Integrity In High Frequency, High Density Circuit Boards, Juan Manuel Talavera Martinez

Theses

The electronics market is continually seeking fast and small high performance products. The clock frequency in computer systems is often above 2GHz and new generations of laptops have considerably reduced in size. These features make printed circuit board (PCB) design more difficult than in the past.

This thesis is an investigation of the current design of high speed PCB. The complexity of this type of circuit makes the designer needs an extensive knowledge of the techniques used to generate a reliable signalling, in other words, signal integrity. To achieve this objective, the design community has to overcome several problem related …