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For many years the analysis of dynamic signals obtained from aero engine mounted transducers has been performed either by using real time spectrum analysers within the test facility, or by making high quality tape recordings during engine tests and analysing the data via an off-line main frame computer. Although real time analysers produce the information where it is most needed, they provide no history of events and the results are operator dependent. Analysis from tape recordings enables information extraction algorithms to be performed and tables and graphs of notable events to be printed. However much of this information could be more effectively utilised if produced within the test facility and in real time. This thesis describes the design and development of a real time data acquisition, signal processing and information extraction system ideally suited for engine health and performance monitoring within test facilities. The thesis begins with a detailed description of the problems encountered in dynamic signal analysis in the field of aero engine performance testing, and with an overview of digital signal processing and the latest technology signal processing micro processors that have made this project possible. It then describes the problems encountered and the subsequent solutions found during the design and development of the hardware and software needed for the·high bandwidth data acquisition and fast signal processing algorithms. The fast Fourier transform has been used for very many years in the field of spectrum analysis, ... however this technique has limitations which are overcome by some of the more modern spectrum estimation techniques. This thesis makes an assessment of some of these techniques, noting particularly their performance on aero engine type signals. The results of these tests are recorded and the possible use of the techniques in aero engine analysis is discussed.

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This thesis deals with some of the theoretical and practical aspects relating to the conversion gain and noise performance of mixers employing dual-gate field effect transistors (DGFET'S) . To start with, the role of mixers in the context of radio conununication receivers is highlighted and the most relevant mixer properties are explained. Solid state mixing devices and their circuits are then discussed with special emphasis on the DGFET.This includes a survey and explanation of mixing devices ,planar transmission lines and circuit components for the practical design of mixers. Chapter 3 then deals with the mixer signal analysis as well as accuracy considerations. A more detailed treatment of the DGFET in terms of structure and dc model is given in the subsequent chapter. Problems associated with the choice of an FET model are referred to as well as the use of MATLAB for computationa: purposes. This is followed in the next two chapters with the development and analysis of the large signal equivalent circuit of tr.{· DGFET,and a treatment of noise and its measurement as associated with mixers. The design, practical implementation and measurement of the properties of DGFET mixers is covered in chapter 7. This is followed in Chapter 8 by an overall discussion of results, possible future work and conclusions. A new FET model is proposed that enables the dc characteristics to be simulated more closely than in previous models, particularly at low drain voltages. Furthermore, the representation of the noise by a frequency independent drain current generator and an input noise conductance enabled a single set of measurements to simulate the noise behaviour of the device as an amplifier or a mixer. Practical investigations using an NEe device type NE 41137 gave a maximum stable conversion gain in the frequency range O.SGHz to 3.0GHz of 4dB with a minimum noise figure 8.SdB.

Electrocardiography (ECG) monitor is a medical device for recording the electrical activities of the heart using electrodes placed on the body. There are many ECG monitors in the market but it is essential to find the accuracy with which they generate results. Accuracy depends on the processing of the ECG signal which contains several noises and the algorithms used for detecting peaks. Based on these peaks the abnormality in the functioning of the heart can be estimated. Hence this thesis characterizes the ECG signal which helps to detect the abnormalities and determine the accuracy of the system.

The Nanopore Detector using á-hemolysin channel transcribes kinetics of a single molecule along the nanometer-scale pore. The transcribed data is represented by electrical measurements. We present accurate and computationally inexpensive tools to analyze single molecule kinetics. The HMM-EM level projection method de-noises data, retaining the transitions with very high precision. This approach doesn't require input number of levels. Another advantage is the minimal tuning required. The levels are then identified using Finite State Automata (FSAs). Spike Detector algorithm analyzes spikes characterizing behavior of molecule in pore. No commercial tools available are capable of analyzing spikes in presence of noise. The formulation of HMM-EM, FSAs and Spike Detector together provides a robust method for analysis of channel current data. Application of these methods is described for Vercoutere channel blockade dataset which contains signals of radiated and non-radiated molecules. The tools developed were used successfully to differentiate between these two molecules.

This thesis proposes the small signal model for the Interline Power Flow Controller (IPFC). Using this model, the damping performance of the IPFC with different power system configuration is investigated and also compared with the AC Transmission System (FACTS) based controllers such as the Unified Power Flow Controller (UPFC). The IPFC and the UPFC in constant power control mode can be viewed as effectively cutting the connected transmission line. This change on the structure of the network results in a significant change on the small signal stability. This thesis also addresses issues regarding the different levels of models that are required for the investigation of the behavior of FACTS. An effective validation approach that uses a minimum sized demonstration platform is proposed. This platform is small enough for detailed EMTP validation, yet large enough to exhibit the range of transient electrical and electromechanical behavior which is the focus for FACTS devices. To demonstrate the approach, the small signal models of the system embedded with the IPFC and the UPFC are developed respectively. The results obtained from small signal analysis are validated with EMTP-type simulation and show a close agreement.

This thesis proposes the small signal model for the Interline Power Flow Controller (IPFC). Using this model, the damping performance of the IPFC with different power system configuration is investigated and also compared with the AC Transmission System (FACTS) based controllers such as the Unified Power Flow Controller (UPFC). The IPFC and the UPFC in constant power control mode can be viewed as effectively cutting the connected transmission line. This change on the structure of the network results in a significant change on the small signal stability. This thesis also addresses issues regarding the different levels of models that are required for the investigation of the behavior of FACTS. An effective validation approach that uses a minimum sized demonstration platform is proposed. This platform is small enough for detailed EMTP validation, yet large enough to exhibit the range of transient electrical and electromechanical behavior which is the focus for FACTS devices. To demonstrate the approach, the small signal models of the system embedded with the IPFC and the UPFC are developed respectively. The results obtained from small signal analysis are validated with EMTP-type simulation and show a close agreement.