https://www.um.edu.mt/library/oar/handle/123456789/14669 Tue, 28 Apr 2026 04:03:21 GMT 2026-04-28T04:03:21Z https://www.um.edu.mt/library/oar/handle/123456789/101436 Title: High performance CMOS frequency synthesis architectures for microwave applications Abstract: The motivation of this research was to investigate novel low voltage microwave frequency synthesizer architectures which can provide a wide range of frequencies with an acceptable phase noise response, integrated spurious level and power consumption as required by modem communication systems. In particular the work undertaken and described in this dissertation can be classified into three main parts. The first part reports the study, design and silicon implementation of a low voltage 1.6 GHz quadrature output integer-N phase locked loop based frequency synthesizer with an on-chip regulated DC-DC converter in order to achieve a wide tuning range with negligible effect on the phase noise and spurious level. The second part discusses the investigation of the use of a Micro-electro-mechanical Systems (MEMS) based tuneable inductor both as a means to extend the frequency tuning range and also to facilitate and improve the voltage-controlled oscillator design in terms of phase noise response and power consumption in comparison to a design based on conventional capacitive tuning. Finally, the last part of the dissertation discusses the investigation of the spurious tone levels in novel digitally based frequency synthesis architectures for an Ultra Wideband MB-OFDM (Multi-band Orthogonal Frequency Division Multiplexing) Alliance application which requires a wide range of frequencies. Architectures are proposed as low silicon area alternatives to state-of-the-art solutions. Description: PH.D. Fri, 01 Jan 2010 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/101436 2010-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/95821 Title: A generic generic algorithm using phenotype building functions Abstract: The problem with genetic algorithms is that their use is made difficult by the fact that they are not very reusable because the chromosome representation, genetic operators and fitness function need to be redefined for many problems. In order to use a genetic algorithm you have to think in terms of evolution which might not be easy for a programmer. In this project, we aim to solve these problems by creating a generic chromosome representation which always uses the same genetic algorithm regardless of the problem being solved. The user then directs the genetic algorithm by writing a function, called the 'phenotype building function' or the 'builder function', which maps the generic chromosome into candidate solutions. The fitness function will still have to be provided in order to measure the fitness of a candidate solution. Description: B.Sc. IT (Hons)(Melit.) Fri, 01 Jan 2010 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/95821 2010-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/95804 Title: Aircraft autoland system using fuzzy logic Abstract: A full aircraft Autoland system using fuzzy logic has been developed. It is based on the flight model of a medium sized commercial airliner (Boeing 73 7-800), and was designed for a full 6 degree of freedom flight simulator. This was achieved by implementing several independent single output Fuzzy Controllers that are able to work together based on instrument readings continuously taken from the aircraft. Scenarios the solution was tested in include varying glidepath angles, various weather situations that include severe stable crosswinds and severe gusting crosswinds. For each case, the final results show that not only were safe landings performed in cases where the conditions were within the limitations set by the aircraft's manufacturer but also in worse conditions. These include landing in airports with a steep glidepath angle (such as London City Airport) but also landing in extreme crosswind conditions nearly double that of what the manufacturers recommend is used as a limitation. Description: B.Sc. IT (Hons)(Melit.) Fri, 01 Jan 2010 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/95804 2010-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/95632 Title: Implementation of a baseband GPS receiver Abstract: The Global Positioning System (GPS) is a space-based radio navigation system which was originally developed for military use. However, GPS receivers have become more popular in recent years and are now incorporated in mobile phone electronics and also in navigation systems, namely in automotive, marine and aerospace equipment. This thesis focuses on digital signal processing (DSP) performed by a typical L 1-hand Cl A-code receiver. Such baseband processing mainly involves local carrier and pseudo-random noise (PRN) code generation, converting the incoming GPS signal down to baseband, correlating the resulting baseband signal with the locally generated codes, determining the available satellites and subsequently choosing at least four of them, phase-aligning the local and incoming codes of the selected satellites, and finally, detecting and demodulating the navigation messages from the individual selected satellites. Thus, this dissertation presents the design and implementation of various DSP and communication blocks which are responsible for such baseband processing. In this work, perfect carrier phase recovery is assumed. These baseband digital modules are implemented on an FPGA. Such approach allows additional flexibility in the implementation when compared to the ASIC approach, due to the chip's reprogrammability feature. The functionality of each module is tested and verified. A GPS satellite signal modulation model is also developed to test and simulate the baseband processor for different scenarios, for example for multiple satellite transmissions and in the presence of noise. From these tests, it is noted that as the number of parallel transmissions is increased or when the SNR is decreased, the correlation between the incoming and local codes of the visible satellites is reduced. The minimum SNR value that the designed baseband processor can tolerate is -10 dB. For SNR values greater than or equal to this value, it is guaranteed that navigation messages from the different selected satellites are decoded correctly. This only holds if automatic gain control is adopted. If no gain control is used, the minimum SNR value that the processor can tolerate is greater than -10 dB. Good noise performance is crucial in GPS receivers since, in practice, the noise power level is significantly greater than the actual GPS signal power level. Description: B.SC.(HONS)COMPUTER ENG. Fri, 01 Jan 2010 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/95632 2010-01-01T00:00:00Z