Parametric Investigation of Near End and Far End Crosstalks in Printed Circuit Board Lands

Multi-conductor transmission line and interconnect carry signals with wide rage of frequencies from sending end to receiving end. The signal in one transmission line may be interupted by the unwanted contributions from the neighboring line conductors. If data speed increases, high frequency effects occur and the signals suffer from difficulties such as ringing, crosstalk, reflections, and ground bounce that seriously hamper the quality of the received signal. In order to estimate the signal quality, signal integrity analysis is needed. In this paper, an attempt has been made to investigate the sensitivity of the near and far end crosstalk on the parameters such as physical geometry of the conductors, electrical property of the substrate and the rise and fall time of excitation signal. The method of moments (MOM) is used to calculate the line parameters for different geometries. The simulation studies are carried out in TNT. The time domain and frequency domain analyses are performed using transmission line model of PSPICE. Moreover, a model is developed and tested in the laboratory. It is observed that the coupling inductance and capacitance vary with the variation of physical geometry and the substrate parameter

Efficient Computation of Cable Electromagnetic Compatibility Problems with Parametric Uncertainty

Cables are heavily used to transmit power and signals in various systems. However, due to the susceptibility of cable to conducted and radiated emissions, unintended response could be provoked in the cable, and therefore, degrade the system operation. This is referred to as the cable electromagnetic compatibility (EMC) problems. Deterministic simulations based on the nominal values of system variables are usually performed to predict the possible malfunction. However, the variables characterising the cable system are naturally random due to, e.g. manufacturing tolerance. As a result of the systemic uncertainty, the induced interference in the cable also becomes a random observable. Therefore, the statistical description of the cable interference is a more reasonable outcome for assessing the system risk. Accordingly, stochastic approaches are needed to produce the required statistical outcome. The conventional statistical approach to quantify the uncertainty of the system response is the Monte-Carlo (MC) method. However, the computational cost of the MC method could become overly expensive when dealing with a large number of random variables. Thus, the cable EMC problems in large platforms with multiple uncertainty sources cannot be efficiently solved using the MC method. Clearly, an efficient statistical approach needs to be sought to solve the challenging cable EMC problems in the real world. Very recently, the stochastic reduced order model (SROM) method was proposed in the field of mechanical engineering, and is known to have merits such as the non-intrusiveness feature and superior efficiency. Therefore, the potential of applying the SROM method for cable EMC problems is very promising, and thoroughly investigated in this thesis. This thesis presents a comprehensive study of the cable EMC problems. The contributions of this thesis are mainly twofold, comprising the investigation of cable interference caused by: (1) the conducted emission (mainly at intra-system level), and (2) the radiated emission when exposed to incident electromagnetic fields. In the case of parametric uncertainty, the statistical analysis of the induced interference is efficiently performed using the SROM method. Specifically, the first main contribution of this thesis is dedicated to the study of crosstalk phenomenon, i.e., the inference induced to a wire by nearby wires in the cable. A parametric study is performed to investigate the effect (i.e., by increasing or decreasing) of the cable configurational changes on the crosstalk variation. The result can also be used to suggest factors causing excessive crosstalk. Under the cable parametric uncertainty, the statistics of crosstalk is successfully predicted using the SROM method. The efficiency of the statistical analysis using the SROM method and its ease of implementation are clearly demonstrated, compared to the conventional MC method and another state-of-the-art statistical approach referred to as the stochastic collocation (SC) method. The sensitivity of crosstalk to different cable variables is efficiently quantified using the SROM method, and then ranked. With this ranking, the feasibility of reducing the complexity of stochastic EMC problems by ignoring weak parametric uncertainties is explored. The second significant contribution of this thesis is the efficient uncertainty quantification of the interference in the cable caused by random electromagnetic field illumination. The most complex scenario where the incident electromagnetic wave is assumed to be fully random is chosen for investigation. As a response to the random illumination, the statistics of the interference (i.e., the induced current) in the cable is efficiently obtained using the SROM method. The computational cost of the SROM method is shown to be significantly reduced by orders of magnitude, compared to those of the MC and SC methods. The result demonstrates the potential of the SROM method for the general problems of the cable system response to the random radiation field. Overall, the research presented in this thesis has successfully advanced the uncertainty propagation techniques for EMC problems, especially in the case of the cable interference. Based on the performance discussion, this thesis has also provided an in-depth knowledge about the merits and disadvantages of different stochastic methods, which helps EMC engineers perform the efficient statistical analysis for their specific problems

Search for relativistic magnetic monopoles with the AMANDA detector

Diese Arbeit beschreibt die Suche nach relativistischen magnetischen Monopolen mit dem AMANDA Detektor. Die Methoden der Simulation und der Untergrundseparation werden erläutert. Keine Spuren mit der Signatur eines magnetischen Monopols wurden gefunden. Das sich ergebende Flusslimit von 0.61x10^-16 1/(cm^2 sr s) für Monopole, die sich nahe der Lichtgeschwindigkeit bewegen, liegt um einen Faktor 3-4 besser als die Ergebnisse vergleichbarer Untergrundexperimente und einen Faktor 16 unterhalb der Grenze, die aus der beobachteten Stabilität der galaktischen Magnetfelder liegt.This thesis describes the search for relativistic magnetic monopoles with the AMANDA detector. The methods of their simulation and their separation from the background are given. No tracks with the signature of a magnetic monopoles are found, resulting in an upper limit on the flux of 0.61x10^-16 1/(cm^2 sr s) for monopoles with velocities close to the speed of light. This is better by a factor of 3-4 compared to results from other underground detectors and a factor of 16 below the limit derived from the observed stability of the galactic magnetic fields

Design of a modular digital computer system, DRL 4

The design is reported of an advanced modular computer system designated the Automatically Reconfigurable Modular Multiprocessor System, which anticipates requirements for higher computing capacity and reliability for future spaceborne computers. Subjects discussed include: an overview of the architecture, mission analysis, synchronous and nonsynchronous scheduling control, reliability, and data transmission

Wavelength reconfigurability for next generation optical access networks

Next generation optical access networks should not only increase the capacity but also be able to redistribute the capacity on the fly in order to manage larger variations in traffic patterns. Wavelength reconfigurability is the instrument to enable such capability of network-wide bandwidth redistribution since it allows dynamic sharing of both wavelengths and timeslots in WDM-TDM optical access networks. However, reconfigurability typically requires tunable lasers and tunable filters at the user side, resulting in cost-prohibitive optical network units (ONU). In this dissertation, I propose a novel concept named cyclic-linked flexibility to address the cost-prohibitive problem. By using the cyclic-linked flexibility, the ONU needs to switch only within a subset of two pre-planned wavelengths, however, the cyclic-linked structure of wavelengths allows free bandwidth to be shifted to any wavelength by a rearrangement process. Rearrangement algorithm are developed to demonstrate that the cyclic-linked flexibility performs close to the fully flexible network in terms of blocking probability, packet delay, and packet loss. Furthermore, the evaluation shows that the rearrangement process has a minimum impact to in-service ONUs. To realize the cyclic-linked flexibility, a family of four physical architectures is proposed. PRO-Access architecture is suitable for new deployments and disruptive upgrades in which the network reach is not longer than 20 km. WCL-Access architecture is suitable for metro-access merger with the reach up to 100 km. PSB-Access architecture is suitable to implement directly on power-splitter-based PON deployments, which allows coexistence with current technologies. The cyclically-linked protection architecture can be used with current and future PON standards when network protection is required