The thesis focuses on a higher order noise-shaping Δ ADC architecture which employs filtered quantization error as a dither signal. Furthermore, the work studies implementation challenges using Switched-Capacitor and Switched-Current techniques. Digitization in an IF conversion receiver can be accomplished either with a wide band Nyquist rate ADC or a BandPass Δ ADC. The use of the latter is the optimum solution since the bandwidth of the IF signals is typically much smaller than the carrier frequency and reducing the quantization noise in the entire nyquist band becomes superfluous. Instead by using BandPass Δ ADCs the quantization noise power is reduced only in a narrow band around IF location. We study state-of-the-art high dynamic range Δ data converter topologies suited for wide-band radio receivers. We propose a topology which achieves higher order noise shaping by employing filtered quantization error as a dither signal. We study implementation challenges for Δ converters in digital technology. Traditionally, Δ ADCs used Switched-Capacitor (SC) circuits to realize their building blocks. This analog sample-data technique is based on the idea that a periodically switched capacitor can emulate a resistor. The limiting factor that degrades the performance of SC circuits implemented in standard VLSI technologies is the continuous reduction of supply voltages, prompted by the continuous scaling-down process. This fact, which is advantageous for digital circuitry, makes the design of SC circuits difficult, which are forced to use clock boosting strategies for switches and to increase the power consumption in order to obtain high-speed and high dynamic range opamps with low voltage operation. In this scenario, the use of current-domain sampled data technique, also named Switched-Current (SI), instead of voltages results advantageous for several reasons. As the signal carriers are currents, the supply voltage does not limit the signal range as much as in SC circuits. Therefore, SI circuits are more suitable than SC for low-voltage operation. This work studies the feasibility and bottlenecks of implementing Δ modulator building blocks using SI technique. A BandPass filter, DAC and 1-bit quantizer have been designed in 0.18µm technology using SI technique. (For mathematical equations pl refer the pdf file)

Les méthodes d'ingénierie acoustique (e.g. ISO 9613-2 ou CNOSSOS-EU) approchent efficacement les niveaux de bruit générés par les routes, les voies ferrées et les sources industrielles en milieu urbain. Cependant, ces approches d'ingénierie sont limitées à des géométries de forme simple, le plus souvent de section rectangulaire. Ce mémoire développe donc, et valide, une approche hybride permettant l'extension des méthodes d'ingénierie à des formes plus complexes, en introduisant un terme d’atténuation supplémentaire qui représente l'effet d'un objet réel comparé à un objet simple.Le calcul de cette atténuation supplémentaire nécessite des calculs de référence, permettant de quantifier la différence entre objets simple et complexe. Dans la mesure où il est trop onéreux, numériquement, '’effectuer ce calcul pour tous les chemins de propagation, l'atténuation supplémentaire est obtenue par interpolation de données stockées dans un tableau et évaluées pour un large jeu de positions de sources, de récepteurs et de fréquences. Dans notre approche, le calcul de référence utilise la méthode BEM en 2.5D, et permet ainsi de produire les niveaux de référence pour les géométries simple et complexe, tout en tabulant leur écart. Sur le principe, d'autres approches de référence pourraient être utilisées.Ce travail valide cette approche hybride pour un écran en forme de T avec un sol rigide, un sol absorbant et un cas avec bâtiments. Ces trois cas démontrent que l'approche hybride est plus précise que l'approche d’ingénierie standard dans des cas complexes. / Noise engineering methods (e.g. ISO 9613-2 or CNOSSOS-EU) efficiently approximate sound levels from roads, railways, and industrial sources in cities. However, engineering methods are limited to only simple box-shaped geometries. This dissertation develops and validates a hybrid method to extend the engineering methods to more complicated geometries by introducing an extra attenuation term that represents the influence of a real object compared to a simplified object.Calculating the extra attenuation term requires reference calculations to quantify the difference between the complex and simplified objects. Since performing a reference computation for each path is too computationally expensive, the extra attenuation term is linearly interpolated from a data table containing the corrections for many source and receiver positions and frequencies. The 2.5D boundary element method produces the levels for the real complex geometry and a simplified geometry, and subtracting these levels yields the corrections in the table.This dissertation validates this hybrid method for a T-barrier with hard ground, soft ground, and buildings. All three cases demonstrate that the hybrid method is more accurate than standard engineering methods for complex cases.