Simulering är en viktig del av utvecklingsarbetet för nya datorkort hos Centre of Excellence - Computers på Saab AB i Jönköping. Ju tidigare i utvecklingsarbetet som defekter och svagheter hos designen hittas desto enklare och mindre kostsamma blir ändringarna att införa. På CoE används simulerings och analysverktyget HyperLynx från Mentor Graphics för att simulera alla kritiska nät. På så sätt kan svagheter hos en design hittas redan innan prototypstadiet. För att simulatorn ska vara användbar krävs dock en kunskap om hur dess resultat korrelerar med verkligheten. Det leder till den övergripande frågeställningen för detta arbete, hur väl överensstämmer HyperLynx simuleringsresultat med verkligheten? Frågeställningen besvarades genom att jämföra simuleringsresultat med motsvarande uppmätta signaler på ett testkort. Resultaten visar att HyperLynx håller en mycket god kvalitet. För signalen i helhet överensstämmer kurvformerna väl både när det gäller vilka reflektioner som bildas och timingen för reflektionerna. Enda genomgående skillnaden mellan simuleringarna och mätningarna visar på något för små amplituder för de simulerade reflektionerna. / Simulations are an important part of the process of designing new computer boards at the Centre of Excellence - Computers at Saab AB in Jönköping. The earlier problems and weaknesses in the design can be found during the design process the less time and money it will take to fix them. The engineers at CoE uses HyperLynx, an analysis and simulation software from Mentor Graphics, to simulate all the critical nets at the board. By doing so, the majority of the problems can be fixed before the prototyping stage. However, the engineers need to know how the simulated signals relate to real signals if the simulator is to be useful. Therefore the question to be answered in this study is how well does the simulated signals in HyperLynx imitate real signals? The question was answered by comparing simulated signals with measurements of corresponding signals on a test board. Overall the shapes of the signals are matching for both which reflections occurs and the timing of the reflections. The only noticeable difference found throughout the study is a slightly smaller amplitude of the reflections for the simulated signals compared to the corresponding measured signal. Due to these results, HyperLynx can be considered a high quality simulator.

In this thesis, we will discuss aging line detection and electrical fire precaution by using powerline communication technique. Fire is always a serious disaster which endangers our lives and property. Electrical fire is a major proportion of fire disaster. Even every house generally setup circuit breaker and fuse in time, electrical fire still occurred oftentimes. Current powerline communication technology is using household powerline as a medium of signal transmission, whose channel characteristic will be affected by surrounding environment. We hope that we can analyze the change of transmission characteristic in high frequency of household powerline, which deterioration during long time. At the same time, we will detect variation of high frequency characteristic of powerline as the basis for judgment of aging line, to prevent electrical fire further. Finally, we combine our approach into PLC system, which can also diagnose the line while transmission of powerline at the same time, adding the value without having too much cost.

A high resolution speedy delivery time domain reflectometer (SD/TDR) has been developed in the Electrical Engineering department at The University of Texas at Austin. The SD/TDR uses a novel non-sinusoidal signal that does not undergo dispersion during transmission in a lossy media. SD/TDR is used to estimate the length and detect the location of faults in the transmission lines. Time of flight (TOF) is one of the critical parameters of SD/TDR and a function of several temperature dependent factors. Given the TOF and length of a transmission line, signal delay can be computed. This research presents an empirical study of the effect of temperature on the TOF in a plenum grade coaxial cable for temperatures ranging from -3 °C to 60 °C. We also study the effect of temperature on characteristic impedance of the coaxial cable. Finally, a SD double exponential waveform is used to estimate TOF for calibrated short and open terminations. / text

Proper design of bridge structures requires an appreciation for the possible failure mechanisms that can develop over the lifetime of the bridge, many of which are related to natural hazards. For example, scour is one of the most common causes of bridge failures. Scour occurs due to the erosion of soil and sediment within a channel with flowing water. During a flood event, the extent of scour can be so great that it can destabilize an existing bridge structure. In order to evaluate the scour potential of a bridge, it is necessary to have information regarding the substructure, particularly the bridge foundations. However, as of 2011 there are more than 40,000 bridges across United States with unknown foundations. Generally for these bridges there are no design or as-built plans available to show the type, depth, geometry, or materials incorporated into the foundations. Several non-destructive testing (NDT) methods have been developed to evaluate these unknown foundations. The primary objective of this research is to identify the most current and widely used NDT methods for determining the embedment depth of unknown bridge foundations and to compare these methods to an ultrasonic P-wave reflection imaging system. The ultrasonic P-wave reflection system has tremendous potential to provide more information and address several short-comings of other NDT methods. A laboratory study was initiated to explore various aspects related to the P-wave system performance, in order to characterize the limitations of the system in evaluation of unknown foundations prior to deployment in field studies. Moreover, field testing was performed using the P-wave system and a number of the current NDT methods at two selected bridge foundations to allow comparison between the results. / Civil Engineering

This thesis deals with a procedure for determining the complete processing of aerodynamic flow instabilities (rotating stall and surge) in a centrifugal compressor. At small flows the performance of a compressor system is limited by the surge line, which is caused by flow instabilities. Numerical solution is obtained using the method of transfer matrix. This system is simulated through several models with local resistances that represent the dissipation of pressure energy. Pulses are excitated in these models by the pressure jump placed before the centrifugal compressor. From the frequency-amplitude characteristics for the selected range of frequencies and flow the impedance characteristic of the compressor system is determined. We are looking for problematic frequencies in this characteristic that cause flow instabilities in the compressor system.