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Title: Large-signal multi-tone domain waveform measurement system with broadband active load impedance control
Author: Williams, Tudor Vyvyan
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2007
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This thesis presents a novel large-signal, multi-tone, time domain waveform measurement and engineering system, which builds upon existing large-signal measurement approaches. The presented system allows for a more considered, and scientific process to be adopted in the design of modern day communications systems. The ultimate aim of this work is to reduce the need for an iterative design approach by providing a measurement system that offers detailed information about a device or circuit without the need for prototyping, it is hoped that such an approach will one day lead to a 'right first time' design approach by allowing ultra-rapid data collection with measurements conducted in realistic environments while employing realistic stimuli. The main contributions to the field of research come in two areas firstly developments that allow for accurate time domain measurement of complex modulated signals using commercially available equipment and secondly in the area of active impedance control, where novel developments were made allowing active control of impedance across a modulated bandwidth. The first research area addressed is the fundamental difficulty in sampling multi-tone waveforms, where the main achievements have been the realisation of a novel frequency-folded and interleaved sampling approach. This approach, with appropriate time-alignment and averaging allows the efficient collection of high-quality vectoral information for all significant distortion terms, for all bands of interest. This means that for the first time off-the-shelf sampling oscilloscopes with limited memory depth can be used capture multi-tone signals in sufficient detail to observe all critical device performance. The second area of research investigated suitable impedance control architectures. Measurement of large-signal multi-tone information is only useful if the broadband impedance environment can also be controlled, only then can we allow a full understanding of the device, and provide the fundamental ability to engineer waveforms for optimum device performance. The main achievement in this area was the development and realisation of a novel architecture that allows active impedance control over a modulated bandwidth.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available