In this thesis, symbol timing recovery based on matched filtering in Gaussian Minimum Shift Keying (GMSK) with bandwidth-bit period product (BT) of 0.3 is investigated. GMSK is the standard modulation type for GSM. Although GMSK modulation is non-linear, it is approximated to Offset Quadrature Amplitude Modulation (OQAM), which is a linear modulation, so that Maximum Likelihood Sequence Estimation (MLSE) method is possible in the receiver part. In this study Typical Urban (TU) channel model developed in COST 207 is used. Two methods are developed on the construction of the matched filter. In order to obtain timing recovery for GMSK signals, these methods are investigated. The fractional time delays are acquired by using interpolation and an iterative maximum search process. The performance of the proposed symbol timing recovery (STR) scheme is assessed by using computer simulations. It is observed that the STR tracks the variations of the frequency selective multipath fading channels almost the same as the Mazo criterion.

In this thesis, we present the spectral and timing variabilities of anomalous X-ray pulsar 1E 2259+586 observed with European Photon Imaging PN Camera (EPIC PN) on board X-ray Multi Mirror Mission (XMM), Proportional Counter Array (PCA) on board Rossi X-ray Timing Explorer (RXTE) and Advanced CCD Imaging Spectrometer (ACIS) on board Chandra X-ray Observatory. We presented the results of spectral analysis of 2000 January 11 ACIS observation. Pulse phase spectroscopy was performed on two XMM observations before and after the outburst. Pulse profiles of two XMM observations before the outburst and three XMM observations after the outburst were studied. Results are consistent with the those presented by Patel et al. (2001) and Woods et al. (2004). We searched for the spectral variations versus spin rate during the outburst. Long-term spectral, frequency and spin-down rate variations are presented between 1996 and 2006 including 98 RXTE and 4 XMM observations. However, except outburst region (Woods et al. 2004) no significant spectral and spin rate variabilities were seen. Around the outburst region we confirmed the spectral hardening with increasing spin rate and flux.

In this thesis, two key issues regarding M-ary orthogonal signaling systems, namely channel estimation and symbol timing recovery are investigated. Kasami codes, which are also called quasi orthogonal codes, are used for transmission of the information in place of orthogonal waveforms. In order to achieve symbol synchronization, a timing recovery scheme based on the Maximum Likelihood (ML) estimation of timing offset is proposed and the effects of proposed structure over the receiver performance are examined by using computer simulations. Moreover, the receiver performance of M-ary orthogonal signals transmitted over multipath fading channel is investigated. Least Square (LS) approach, based on the transmission of known training sequence, is used to estimate the channel impulse response. In addition to this, frame synchronization is employed at the receiver to extract the timing information by determining the start time of the received symbols. Computer simulations related to the proposed receiver structure are carried out in order to observe how the system performance is affected under multipath fading channel. Parameter selection guides regarding a good performance are also provided.

In this thesis, noncoherent differential demodulation of CPM signals with joint carrier frequency offset and symbol timing estimation is investigated. CPM is very attractive for wireless communications owing to major properties: good spectral efficiency and a constant envelope property. In order to demodulate the received CPM signal differentially, the symbol timing and the carrier frequency offset have to be estimated accurately. There are numerous methods developed for the purpose. However, we have not encountered studies (which are based on autocorrelation estimation and hence suitable for blind synchronization) that give expectable performance for both M-ary and partial response signaling. Thus, in this thesis we analyze a feedforward blind estimation scheme, which recovers the symbol timing and the frequency offset of M-ary CPM signals and partial response CPM signals. In addition, we surveyed low complexity symbol detection methods for CPM signals. Reduced state Viterbi differential detector incorporated to the joint frequency offset and symbol timing estimator is also examined. The performance of the examined demodulator scheme is assessed for the AWGN channel by computer simulations.

<p>The last few decades have been a very exciting period in thedevelopment of micro-electronics and brought us to the brink ofimplementing entire systems on a single chip, on a hithertounimagined scale. However an unforeseen challenge has croppedup in the form of managing wires, which have become the mainbottleneck in performance, masking the blinding speed of activedevices. A major problem is that increasingly complicatedeffects need to be modelled, but the computational complexityof any proposed model needs to be low enough to allow manyiterations in a design cycle.</p><p>This thesis addresses the issue of closed form modelling ofthe response of coupled interconnect systems. Following astrict mathematical approach, second order models for thetransfer functions of coupled RC trees based on the first andsecond moments of the impulse response are developed. The2-pole-1-zero transfer function that is the best possible fromthe available information is obtained for the signal path fromeach driver to the output in multiple aggressor systems. Thisallows the complete response to be estimated accurately bysumming up the individual waveforms. The model represents theminimum complexity for a 2-pole-1-zero estimate, for this classof circuits.</p><p>Also proposed are new techniques for the optimisation ofwires in on-chip buses. Rather than minimising the delay overeach individual wire, the configuration that maximises thetotal bandwidth over a number of parallel wires isinvestigated. It is shown from simulations that there is aunique optimal solution which does not necessarily translate tothe maximum possible number of wires, and in fact deviatesconsiderably from it when the resources available for repeatersare limited. Analytic guidelines dependent only on processparameters are derived for optimal sizing of wires andrepeaters.</p><p>Finally regular tiled architectures with a commoncommunication backplane are being proposed as being the mostefficient way to implement systems-on-chip in the deepsubmicron regime. This thesis also considers the feasibility ofimplementing a regular packet-switched network-on-chip in atypical future deep submicron technology. All major physicalissues and challenges are discussed for two differentarchitectures and important limitations are identified.</p>

<p>The goals for most of today’s receiver system are sampling at high-speed, with high resolution and with as few errors as possible. This master thesis describes the design of a high-speed sampling system with"state-of-the-art"components available on the market. The system is designed with a parallel Analog-to-digital converter (ADC) architecture, also called time interleaving. It aims to increase the sampling speed of the system. The system described in this report uses four 12-bits ADCs in parallel. Each ADC can sample at 125 MHz and the total sampling speed will then theoretically become 500 Ms/s. The system has been implemented and manufactured on a printed circuit board (PCB). Up to four boards can be connected in parallel to get 2 Gs/s theoretically. </p><p>In an approach to increase the systems performance even further, a timing error estimation algorithm will be used on the sampled data. This algorithm estimates the timing errors that occur when sampling with non-uniform time interval between samples. After the estimations, the sampling clocks can be adjusted to correct the errors. </p><p>This thesis is concerning some ADC theory, system design and PCB implementation. It also describes how to test and measure the system’s performance. No measurement results are presented in this thesis because measurements will be done after this project. The last part of the thesis discusses future improvementsto achieve even higher performance.</p>

Non-melanoma skin cancer (NMSC), comprised of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), is the most common cancer in Caucasians. Ultraviolet radiation (UVR) exposure is the most important environmental risk factor for both BCC and SCC development. However, the precise relationship between UVR and the risk of NMSC is complex, and the relationship may differ by skin cancer type. It has been hypothesized that intermittent patterns and childhood sunlight exposure are important for BCC while continuous (chronic) and lifelong (i.e. childhood and adulthood) sunlight exposure is important for SCC. Epidemiologic studies have demonstrated that cutaneous human papillomavirus (HPV) infection may also be a risk factor for developing NMSC. However, the pathway by which cutaneous HPV is associated with NMSC remains unclear. It is hypothesized that UVR exposure may interact synergistically with cutaneous HPV in NMSC development. The goal of the research study was to evaluate the relationship between levels of sunlight exposure and BCC and SCC and to investigate differences in sunlight-associated BCC and SCC risk by genus-specific cutaneous HPV serostatus. To address these goals, we conducted a clinic based case-control study of histologically confirmed BCC and SCC cases recruited from a university dermatology clinic and controls with no history of cancer and screened negative for current skin cancer. Logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for the associations between measures of sunlight exposure and BCC and SCC. Multiplicative interactions were tested by placing an interaction term for the product of genus-specific HPV seroreactivity and sunlight related factors in the logistic regression models. Measures of both intermittent and continuous patterns of sunlight exposure were associated with both types of skin cancer (i.e. BCC and SCC). Specifically, history of blistering sunburn (a marker of intermittent sunlight exposure) and occupational sunlight exposure (i.e. having a job in the sun for at least 3 months for >10 years) were both associated with BCC and SCC. The major differences in patterns of sunlight exposure between BCC and SCC were observed for sunlight exposure in one's thirties. Additionally, sunlight exposure in one's twenties was associated with SCC, regardless of pattern of exposure; similar associations were not observed for BCC. Measures of timing of sunlight exposure consistently demonstrated that childhood/adolescent sunlight exposure was more important for SCC than BCC. These included number of moles on the forearms and entire body (measure of increased childhood sunlight exposure), and younger age at first and tanning bed use. Younger age at first blistering sunburn was statistically significantly associated with both BCC and SCC. NMSC cases were more likely to be seropositive for cutaneous HPV antibodies compared to controls. Compared to tanning, having a propensity to sun burn (p=0.006), or poor tanning ability (p=0.003) were significantly associated with a higher seroprevalence to genus beta HPV types within SCC cases. Statistically significant interactions were observed between poor tanning ability and genus-specific seropositivity with NMSC. Specifically, the associations between poor tanning ability and BCC (p interaction=0.02) and SCC (p interaction=0.01) were significantly stronger among individuals that were seropositive for antibodies to genus alpha HPV types. Similarly, the association between poor tanning ability and SCC was stronger among those seropositive for genus beta HPV types (p interaction=0.001). No additional significant interactions were observed for BCC or SCC between cutaneous sensitivity, history of blistering sunburn, or cumulative sunlight exposure and genus-specific seroreactivity. In conclusion, associations with patterns of sunlight exposure appeared to be similar between BCC and SCC cases. With the exception of age at first blistering sunburn, factors measuring timing of sunlight exposure demonstrated stronger and statistically significant relationships with SCC. Additionally, of the sunlight related factors measured, only the associations between poor tanning ability and BCC and SCC were significantly modified by HPV seropositivity to types in genera alpha or beta.

With the high complexity of modern day microprocessors and the slow speed of cycle-accurate simulations, architects are often unable to adequately evaluate their designs during the architectural exploration phases of chip design. This thesis presents the design and implementation of the timing partition of the cycle-accurate, microarchitecture-level SFFSim-Bear simulator. SFFSim-Bear is an implementation of the speculative functional-first (SFF) methodology, and utilizes a hybrid software-FPGA platform to accelerate simulation throughput. The timing partition, implemented in FPGA, features throughput-oriented, latency-tolerant designs to cope with the challenges of the hybrid platform. Furthermore, a fault injection framework is added to this implementation that allows designers to study the reliability aspects of their processors. The result is a simulator that is fast, accurate, flexible, and extensible. / text

The current trend in embedded systems design is to move the initial design and exploration phase to a higher level of abstraction, in order to tackle the rapidly increasing complexity of embedded systems. One approach of abstracting software development from the low level platform details is host- compiled simulation. Characteristics of the target platform are represented in a host-compiled simulation model by annotating the high level source code. Compiler optimizations make accurate annotation of the code a challenging task. In this thesis, we describe an approach to enable correct back-annotation of C code at the basic block level, while taking compiler optimizations into account. / text

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