<p>Comparator is the main building block in an ADC architecture. Main purpose of the comparator is to compare a signal with a reference signal and produce an output depending on whether the input signal is greater or smaller than reference. Many architectures for comparators exist for various purposes. In this thesis, Latched comparator architecture is used for sigma delta modulator. This particular design has two main characteristics that are very important for sigma delta application. First characteristic is the cancellation of memory effect which increases the speed and reliability of the system and the second is, with this architecture, high sensitivity can be achieved.</p><p>The design and implementation of lathed comparator for sigma delta modulator is presented in this thesis work. Various non-linearities and performance parameters are discussed in detail. Practical implementation and circuit design issues are highlighted to achieve maximum sensitivity along with reasonable speed and accuracy.</p>

<p>This thesis discusses and investigates the estimation of carrier offset frequency in</p><p>orthogonal frequency division multiplexing (OFDM) mobile systems. The investigation</p><p>starts by using Mobile WiMAX wireless communication specifications described</p><p>in IEEE 802.16e as the primary system setup. Under this setup orthogonal</p><p>frequency division multiple access (OFDMA) is used as a physical layer scheme; it</p><p>also involves the use of pilots in the OFDM symbol for channel estimation.</p><p>Although OFDM is resistant to multipath fading, it requires a high degree of synchronisation</p><p>to maintain sub-carrier orthogonality. Therefore the level of performance</p><p>of the system depends first on the accuracy in estimating the carrier frequency</p><p>offset and then the estimation of the channel. Maximum likelihood estimator</p><p>is used for estimating carrier frequency offset; its performance under different conditions</p><p>for example SNR, number of virtual carriers needed for estimation etc. are</p><p>simulated and compared with theoretical results. The optimality of IEEE 802.16e</p><p>specifications was also examined during the simulations and results analysis.</p>

This dissertation analyzes the basis for and magnitudes of discount factors based on the characteristics of greenhouse gas emission (GHGE) offsets that are applied to the GHGE reduction projects, concentrating on agricultural projects. Theoretical approaches to discount factors, estimation and incorporation of discount factors procedures are developed. Discount factors would be imposed by credit purchasers due to noncompliance with regulatory program of the credits with GHG program including consideration of shortfall penalties and limited durations. Discount factors are proposed for (i) additionality, (ii) leakage, (iii) permanence, and (iv) uncertainty. Additionality arise when the region where an AO project is being proposed would have substantial adoption of the AO practice in the absence of GHG programs (business as usual GHGE offset). Leakage arises when the effect of a program is offset by an induced increase in economic activity and accompanying emissions elsewhere. The leakage effect depends on demand and supply elasticities. Permanence reflects the saturation and volatility characteristics of carbon sequestration. Carbon is stored in a volatile form and can be released quickly to the atmosphere when an AO practice is discontinued. The permanence discount depends on the project design including practice continuation after the program and the dynamic rate of offset. Also, consideration of multiple offsets is important. Uncertainty arises due to the stochastic nature of project quantity. The uncertainty discount tends to be smaller the larger the size of the offset contract due to aggregation over space and time. The magnitude of these discounts is investigated in Southeast Texas rice discontinuation study. The additionality and the leakage discounts are found to play an important role in case of rice lands conversion to other crops but less so for pasture conversions and yet less for forest conversions. The permanence discount is important when converting to other crops and short rotation forestry. When all discounts are considered, rice lands conversion to forest yields claimable credits amounting to 52.8% ~ 77.5% of the total offset. When converting rice lands to pasture, the claimable credits 45.1% ~ 64.2%, while a conversion of rice lands to other crops yields claimable credits 38.9% ~ 40.4%.

The demand for reliable high rate and efficient communication is ever increasing. In this thesis we look at two different problems in such systems, and their possible solutions. In recent years orthogonal frequency division multiplexing (OFDM) has gone from a promising data transmission technique to become a mainstream technique used in several current and future standards. The main attractive property of OFDM is that it is inherently resilient to multipath reflections because of its long symbol time. However, this comes at the cost of a relatively high sensitivity to carrier frequency offsets (CFOs). In this thesis we present a technique for CFO estimation in OFDM systems that is based on locating the spectral minimas within so-called null or virtual subcarriers embedded in the spectrum.~The spectral minimas are found iteratively over a number of symbols and is therefore mainly useful for frequency offset tracking or in systems where an estimate is not immediately required, such as in TV or radio broadcasting systems. However, complexity wise the estimator is relatively easy to implement and it does not need any extra redundancy beside a nonmodulated subcarrier. The estimator performance is studied both in a channel with additive white Gaussian noise and in a frequency selective channel environment. A goal for many years has been to be able to implement as much as possible of a radio system in the digital domain, the ultimate goal being so called software defined radio (SDR). One important part of an SDR receiver is the high speed analog-to-digital converter(ADC) and one path to reach this goal is to use a number of parallel, time-interleaved, ADCs. Such ADCs are, however, sensitive to sampling instant offsets, DC offset and gain offset. This thesis also discusses iterative time-delay estimators (TDEs) utilizing adjustable fractional-delay filters. The TDEs could for example be used to estimate and calibrate the relative delay between the ADCs comprising the time interleaved ADC. TDEs using a direct correlator and an average squared difference function are compared. Furthermore, an analysis of the effects of the batch length dependence is presented. / Report code: LiU-Tek-Lic-2006:33.

Anthropogenically forced climate change has emerged as one of the most important, and polarizing, issues of our time. Afforestation generated carbon offset projects hold a position in Canada as potentially influential, yet frustratingly under-utilized, options to mitigate climate change. This dissertation responds to the question, “what are the economic implications of afforestation generated carbon offset institutions in Canada – and how appropriate are the tools of the New Institutional Economics (NIE) in their identification?” I establish the context for discussion by arguing that the NIE, as practiced, seems incapable of providing rigorous analysis while simultaneously responding to questions of power and distribution. The case of afforestation generated carbon offset marketing is presented as an appropriate context for exploring this point. A literature review is then used to establish general patterns regarding aggregating institutions for offset production and marketing, and aggregating institutions are presented as a response to the effects of transaction costs on the Canadian offset market. I then develop supply and demand curves to describe the equilibrium state of the Canadian offset market, into which the transaction costs borne by three aggregators are integrated. Their performance in fulfilling various policy objectives is evaluated. The results indicate that the primary variation between scenarios is the distribution of benefits. This focus on the distribution of benefits continues through demonstrating how subtle variations in modeling coefficients affect the regional distribution of afforestation projects within Canada, identifying the power associated with policy maker ideology. The role of policy maker ideology is then explicitly examined through a survey of government analysts and technicians and the application of discriminant analysis. The primary axes of afforestation ideology are identified, and demonstrated to be independent of concerns of transaction costs and aggregation. These results are integrated to argue that distributional concerns, particularly when ideologies are active in informing policy maker preferences, are critical to achieving sustainable policy outcomes, and that the NIE can respond to such concerns, but only if reform takes place to legitimate these techniques as part of the standard economic discourse.

Orthogonal Frequency Division Multiplexing (OFDM) plays an important role in the implementation of high data rate communication. In this thesis, the problems of data detection and channel and carrier frequency offset estimation in OFDM systems are studied. <p>Multi-symbol non-coherent data detection is studied which performs data detection by processing multiple symbols without the knowledge of the channel impulse response (CIR). <p>For coherent data detection, the CIR needs to be estimated. Our objective in this thesis is to work on blind channel estimators which can extract the CIR using just one block of received OFDM data. A blind channel estimator for (Single Input Multi Output) SIMO OFDM systems is derived. The conditions under which the estimator is identifiable is studied and solutions to resolve the phase ambiguity of the proposed estimator are given.<p>A channel estimator for superimposed OFDM systems is proposed and its CRB is derived. The idea of simultaneous transmission of pilot and data symbols on each subcarrier, the so called superimposed technique, introduces the efficient use of bandwidth in OFDM context. Pilot symbols can be added to data symbols to enable CIR estimation without sacrificing the data rate. Despite the many advantages of OFDM, it suffers from sensitivity to carrier frequency offset (CFO). CFO destroys the orthogonality between the subcarriers. Thus, it is necessary for the receiver to estimate and compensate for the frequency offset. Several high accuracy estimators are derived. These include CFO estimators, as well as a joint iterative channel/CFO estimator/data detector for superimposed OFDM. The objective is to achieve CFO estimation with using just one OFDM block of received data and without the knowledge of CIR.

Anthropogenically forced climate change has emerged as one of the most important, and polarizing, issues of our time. Afforestation generated carbon offset projects hold a position in Canada as potentially influential, yet frustratingly under-utilized, options to mitigate climate change. This dissertation responds to the question, “what are the economic implications of afforestation generated carbon offset institutions in Canada – and how appropriate are the tools of the New Institutional Economics (NIE) in their identification?” I establish the context for discussion by arguing that the NIE, as practiced, seems incapable of providing rigorous analysis while simultaneously responding to questions of power and distribution. The case of afforestation generated carbon offset marketing is presented as an appropriate context for exploring this point. A literature review is then used to establish general patterns regarding aggregating institutions for offset production and marketing, and aggregating institutions are presented as a response to the effects of transaction costs on the Canadian offset market. I then develop supply and demand curves to describe the equilibrium state of the Canadian offset market, into which the transaction costs borne by three aggregators are integrated. Their performance in fulfilling various policy objectives is evaluated. The results indicate that the primary variation between scenarios is the distribution of benefits. This focus on the distribution of benefits continues through demonstrating how subtle variations in modeling coefficients affect the regional distribution of afforestation projects within Canada, identifying the power associated with policy maker ideology. The role of policy maker ideology is then explicitly examined through a survey of government analysts and technicians and the application of discriminant analysis. The primary axes of afforestation ideology are identified, and demonstrated to be independent of concerns of transaction costs and aggregation. These results are integrated to argue that distributional concerns, particularly when ideologies are active in informing policy maker preferences, are critical to achieving sustainable policy outcomes, and that the NIE can respond to such concerns, but only if reform takes place to legitimate these techniques as part of the standard economic discourse.

Since digital system has become very common today it is important to have good interfaces in between the analog and digital domain. This puts high demandson the analog to digital converter. It is therefore important in the design of theanalog to digital converter to reduce noise and offset as much as possible. That isalso what this analysis is going to consider but in a comparator which is a crucialpart of the analog to digital converter. The comparator consists of a preamplifierand a latch and it is the preamplifier that will be studied here. The analog todigital converter in consider is of PSAR structure. Some other structures will alsobe mentioned in the first part together with some noise theory.

PAPRO operates within the Forest Research company and their mission is to develop value-addingindustry solutions. At present there are no good ways for mills to easily test the printing quality on newsprintpaper. There is a great need for a fast way to do this on different paper qualities; with a laboratory-offset press this can be both a time and money saving method. At PAPRO Forest Research, NewZealand, a laboratory offset press has been developed and designed, during the past seven years, concerningthis issue. Earlier projects were made concerning the press, e.g. to establish the optimal settings.The mission with this project was to partly determine the present variability of the print quality andto evaluate if the fountain solution, distilled water and 2% Diol green concentrate, used at the momentmixed with different percentages of Isopropanol could decrease the variability and contribute to morestabile results. Throughout the whole project the print quality showed a high variation and was evenmore variable when the Isopropanol was added. All in all 50 print rounds times twelve printed paperstrips was carried out through the project divided into three parts. To analyse the print quality, amicroscope with an image capture camera has been used. Data from the taken images was analysedand inserted into charts to see the variations.The conclusions of the whole project are not satisfying because no final evaluations were possible tomake. Main conclusions are that the additive of Isopropanol to the ordinary fountain solution, used atpresent, only contributed to more unstable results of the print quality. And it seems to be difficult toget some stable results from the lab press as long as the room where it is placed is not fully conditionedas required for the process of offset printing. And the fact that the airbrush which applies theamount of fountain solution is also variable, as shown in earlier projects, which contributes to unstableresults as well. For further work more exact parameters as a conditioned room are required and thepossibility to further design the laboratory press to use waterless offset printing instead.

Bobergs printing house in Falun has during some time had problems regarding deposits on blankets intheirs Müller Martini UV-printing presses. Deposits appear in both image areas and non-image areas.These areas have been analyzed and the deposits on non-image areas contain chalk, clay and talc. Thequestion remains how these material bond to the blanket surface. The chalk and clay comes from thepaper. The talc comes from the ink. Deposits from image areas contain pigment and talc from the printingink. The dampening water has also been analyzed. The result shows some sort of problem with thehardness regulator for the clean water. The pH-level should be increased a few steps.