The challenges for the next generation of integrated circuit (IC) design of analogue and mixed-signal building blocks in standard CMOS technologies for moderate signal conversion in broadband applications, demand research progr~ss in the emerging scientific fields of device physics and modelling, converter architectures, correction algorithms, design automation, technology development, quality assurance and cost factor analysis. The contribution of this thesis to converter architectures is in new topological reusable bUilding blocks for analogue-to-digital (ADC) current converters and improved switching techniques for digital-to-ana.'tlgue (DAC) current converters. A generic compiler for the current folding and interpolating ADC and current steering DAC converter architectures, which take into account the fast technological CMOS changes in an automated down-link towards the basic building blocks, reduces the design time considerably. The new current converter architectures have been realized for 12-bit accuracy in standard CMOS technology. The generic compiler allows fast architectural exploration for other converter specification and the impact on the sizing of the transistors at basic building blocks level for a certain quality specification to be determined. The contributions to modelling, quality assurance and cost factor are the total new concepts in deriving design curves to reduce the design time and to reduce the total chip area of the current converters. For each new technology design curves for standardized transistor sizes for noise level, threshold voltage, I-V curves, overdrive voltage versus lambda and mismatch error modeling of the standard deviation of the drain current for the target operation condition, are automatically derived. For other transistor sizes the values are calculated in an automated procedure. These new design concepts reduce the over-sizing of the transistors, compared to the existing methods, with 15 to 20% for the same quality specification. Besides the reduction of the silicon cost also the design time cost is reduced considerably.

No description available.

No description available.

No description available.

No description available.

The work explores extending time interleaving in A/D converters, by applying a high-level of parallelism to one of the slowest and simplest types of data-converters, the counter ADC. The motivation for the work is to realise high-performance re-configurable A/D converters for use in multi-standard and multi-PHY communication receivers with signal bandwidths in the 10s to 100s of MHz. The counter ADC requires only a comparator, a ramp signal, and a digital counter, where the comparator compares the sampled input against all possible quantisation levels sequentially. This work explores arranging counter ADCs in large time-interleaved arrays, building a Time Interleaved Counter (TIC) ADC. The key to realising a TIC ADC is distributed sampling and a global multi-phase ramp generator realised with a novel figure-of-8 rotating resistor ring. Furthermore Counter ADCs allow for re-configurability between effective sampling rate and resolution due to their sequential comparison of reference levels in conversion. A prototype TIC ADC of 128-channels was fabricated and measured in 0.13μm CMOS technology, where the same block can be configured to operate as a 7-bit 1GS/s, 8-bit 500MS/s, or 9-bit 250MS/s dataconverter. The ADC achieves a sub 400fJ/step FOM in all modes of configuration.

The main objective of this research is to model and analyse complex electromagnetic problems by means of a new hybridised computational technique combining the frequency domain Method of Moments (MoM), Finite-Difference Time-Domain (FDTD) method and a subgridded Finite-Difference Time-Domain (SGFDTD) method. This facilitates a significant advance in the ability to predict electromagnetic absorption in inhomogeneous, anisotropic and lossy dielectric materials irradiated by geometrically intricate sources. The Method of Moments modelling employed a two-dimensional electric surface patch integral formulation solved by independent linear basis function methods in the circumferential and axial directions of the antenna wires. A similar orthogonal basis function is used on the end surface and appropriate attachments with the wire surface are employed to satisfy the requirements of current continuity. The surface current distributions on structures which may include closely spaced parallel wires, such as dipoles, loops and helical antennas are computed. The results are found to be stable and showed good agreement with less comprehensive earlier work by others. The work also investigated the interaction between overhead high voltage transmission lines and underground utility pipelines using the FDTD technique for the whole structure, combined with a subgridding method at points of interest, particularly the pipeline. The induced fields above the pipeline are investigated and analysed. FDTD is based on the solution of Maxwell's equations in differential form. It is very useful for modelling complex, inhomogeneous structures. Problems arise when open-region geometries are modelled. However, the Perfectly Matched Layer (PML) concept has been employed to circumvent this difficulty. The establishment of edge elements has greatly improved the performance of this method and the computational burden due to huge numbers of time steps, in the order of tens of millions, has been eased to tens of thousands by employing quasi-static methods. This thesis also illustrates the principle of the equivalent surface boundary employed close to the antenna for MoM-FDTD-SGFDTD hybridisation. It depicts the advantage of using hybrid techniques due to their ability to analyse a system of multiple discrete regions by employing the principle of equivalent sources to excite the coupling surfaces. The method has been applied for modelling human body interaction with a short range RFID antenna to investigate and analyse the near field and far field radiation pattern for which the cumulative distribution function of antenna radiation efficiency is presented. The field distributions of the simulated structures show reasonable and stable results at 900 MHz. This method facilitates deeper investigation of the phenomena in the interaction between electromagnetic fields and human tissues.

Nous présentons dans cette thèse un modèle pour la coordination de la parole dans des interactions dyadiques utilisateur-agent. Selon une approche courante, coordonner la parole reviendrait à éviter les recouvrements de parole et à minimiser les moments de silence entre deux tours, ceci pour rendre plus fluide l’interaction avec l’agent et améliorer l’expérience de l’utilisateur en interaction dialogique avec l’agent. Les interactions humaines montrent néanmoins une coordination plus complexe avec des recouvrements de parole compétitifs ou non compétitifs et des moments de silences longs. Selon notre approche, c’est en permettant cette diversité des situations que nous verrons émerger, entre l’utilisateur et l’agent, une interaction plus fluide et plus crédible, améliorant l’expérience de l’utilisateur avec l’agent. Les échanges de paroles sont néanmoins, par nature, complexes, la coordination se faisant par l’interaction entre locuteur et auditeur plus que par un participant en particulier. Pour capturer cette complexité, nous avons élaboré un modèle mettant l’accent sur une coordination de la parole basée sur un couplage sensorimoteur continu. Sur la base de ce couplage sensorimoteur, le comportement de l’agent n’est pas entièrement contrôlé par ce dernier, mais est émergent de l’interaction entre les participants. Nous montrons la capacité de notre modèle à faire émerger les différentes situations liées à la coordination de la parole humaine à la fois dans une interaction entre deux agents et dans une interaction utilisateur-agent. / In this thesis, we present a model for the coordination of speaking turns in dyadic interactions between users and agents. According to a common view, to coordinate turns means avoiding overlaps and reduces silences between turns. By optimizing turn transitions between users and agents, the user’s experience is expected to be improved. However, observations of human conversations show a more complex coordination of speaking turns between users and agents: awkward silences and overlaps, competitive or not, are common. In order to improve the credibility and the naturalness of the interaction, we must observe the same variability of situations in a user-agent interaction. Nevertheless, coordination of speaking turns is, by nature, complex, the coordination is managed by the interaction between participants more than controlled by one participant alone. To capture this complexity, we elaborated a model emphasizing the continuous sensory-motor coupling existing between the user and the agent. As a result of this sensory-motor coupling, the behavior of the agent is not entirely controlled by the agent but is an emergent property of the interaction between the user and the agent. We show the capacity of our model to make emerge the different situations linked to the coordination of speaking turns in interactions between two agents and between one user and one agent.