· · · Institutional Repository

Broadband infrastructures are advanced telecommunication systems capable of providing high-speed transmission of services. Broadband deployment has the potential to bring valuable new services, stimulate economic activity, advance economic opportunity and improve productivity. For example, the European Commission has stated that "widespread and affordable broadband access is essential to realize the potential of the information society". Despite this general perception, the announced impacts were not yet backed up with factual evidence. Scientifically grounding this perception is an essential input to the development of telecommunication infrastructures related public and private policies. This thesis contributes to clarify the importance of broadband, by investigating the following research questions: 1) what is the state of the art concerning the impact of broadband to organizational productivity; 2) is there any thorough and generally accepted framework to investigate the relation from broadband to organizational productivity; 3) if not, which framework can be used; 4) how can the applicability of such framework be tested; and 5) which conclusions can be derived about the impact of broadband using this framework. The methodology used to investigate these research questions is based on literature reviews and a survey. From a general observation of the results of the survey, it can be concluded that the majority of the interviewees are conscientious of the impact of the digital information networks and broadband on their productivity, but are not able to distinguish broadband from narrowband. In general, they don't care about the types of networks they are using as long as they can do their job. At this stage, no concrete conclusion can be drawn about the impact of broadband, since users are not clarified about the difference between broadband and narrowband networks. Although the relevance of broadband was validated with a literature review, there is a lack of confirmation of the perceived impacts with an empirical validation. A careful re-design of the questions of the questionnaire should be able to clarify to the target population the difference between these two networks. From a scientific perspective, the novelty of this work lies on the application of a novel framework useful to structure the outcomes of broadband impact studies in a valid conceptual way. From an applied perspective, this work can contribute to clarify utopian and opposite dystopian views of broadband, particularly aiming policy makers and organizational managers.

In this thesis report, two sensor systems for measuring the position of a levitated spindle are proposed. An off-the-shelf optical sensor is used and the results of the implementation are discussed. Furthermore a capacitive sensor system is designed, consisting of a capacitive ring, sensor plates and signal conditioning. Testing shows both of these sensor systems can be used with an accuracy of less than 100um, which can be pushed below 10um given more development time. The results of these two sensor systems can be used in a later stage to design a full active magnetic bearing setup.

In the development of wireless sensor networks, the lifetime of a sensor node is always a key design consideration. Since the battery in a sensor node can usually not be recharged or changed, power management is an effective way to extend the network lifetime. The wireless transceiver, also regarded as the ‘main radio’, is a relatively power hungry component in a sensor node. Therefore, an auxiliary always-on hardware ‘wakeup radio’ was proposed in order to reduce the overall power consumption. The wakeup radio listens to the wireless channel whereas the main radio is only active for a rather short time when the wakeup radio receives the packet with a certain pattern. Consequently, the power efficiency becomes a primary concern in the design of wakeup radio. This thesis focuses on the low power design and implementation of a digital baseband subsystem in the wakeup radio. Firstly, the architecture and details of the subsystem are described. Then the design is verified by both a Spartan-3 FPGA board and TSMC90 chips. The design is functional as designed. In the end, the chip measurement setup and results are discussed. The power consumption varies from 2.1 μw to 8.4 μw, within our design target of 10 μw. To our knowledge, it is the first work on the digital implementation and chip measurement of the wakeup radio.

The Universal Transducer Interface (UTI) is a mass-produced interface circuit which can realize the functions of measuring signals of various sensors such as capacitive sensors, resistive-bridge sensors and resistive sensors. For some of the front-ends, an instrumentation amplifier, which is implemented with dynamic-element-matching (DEM) for its feedback structure, is integrated in the chip. In certain UTI modes, this amplifier is used to amplify small output signals of a resistive-bridge sensor or a single resistive sensor before it enters the applied modulator. According to customers’ complaints, the UTI doesn’t work well. This thesis describes how with systematic investigations three problems have been identified. The first one is that undesired offset is introduced by the limited common-mode rejection ability of the instrumentation amplifier. The second one is that for input common-mode voltages higher than 3.4V, the On-resistances of the applied NMOS switches that control the DEM loop, cause the system to be out of function. The third one is that the electromagnetic interference can introduces unwanted noise in the wiring of the external resistive-bridge sensor. Two dynamic-offset-canceling techniques have been proposed and one of them has been realized on board. With these techniques, the offset has been successfully reduced from up to 200μV to about 7 μV. The noise introduced by interference can be eliminated by applying proper shielding.

We model guided modes for an infinitely long metallic structure in the lateral direction that is invariant in the transverse direction, and mechanically supported by a dielectric layer This modeling is done without making any assumptions about the width of the slots relative to the spatial period. We do this by representing the electric field by their Floquet series in combination with a plane wave representation for the field between the plates. Applying the appropriate boundary conditions leads us to a determinantal (or dispersion) equation. Complex solutions to this dispersion equation have been found numerically using a sophisticatedly adjusted downhill method in two dimensions. Finally this new method has been used to show the effect of the variation of four important parameters in the modeling of a periodically loaded open waveguide. These parameters are: the number of space harmonics, the permittivity of the dielectric layer, the slot size and the height of the dielectric layer.

Description of a system for receiving traffic information trough a wifi ad-hoc system.

It is suspected that instability problems in the current generation of lung simulators are caused by its actuator, a brushless DC motor, in combination with the system configuration. The hypothesis is that these problems can be resolved by replacing the actuator with a backdrivable actuator (that is, an actuator that responds well to external force) in a new system. In this BSc Thesis this hypothesis is researched. The backdrivable actuator (in this particular case, a Voice Coil actuator) in a new system can overcome the instability problems.

Lichtshows van live voorstellingen als Parkpop en Lowlands kunnen vloeiender verlopen als de lichtman een oplossing wordt aangereikt om zijn lichtpaneel met minder handelingen te bedienen. Het doel van dit rapport is het presenteren van een ontwerp voor dit concept, de CS-2 genaamd, en het uitwerken van dit ontwerp. Dit rapport gaat in op de hardwareontwikkeling van het concept.

A wireless data transmission system is developed and tested for Super E-paper.

The goal of this project is to analyze video calls over the Internet Protocol (Video over IP) using a simulated IMS environment (IMS-in-a-box). The thesis presents an overview of IMS, its purpose and how it has evolved. The thesis also attempts to give the reader a full and comprehensible understanding of what the IMS is all about, its purpose and why it came into existence. The thesis considers a number of different video call case scenarios that are most likely to be encountered when making video calls over the Internet using the Internet protocol. This analysis focuses mainly on the SIP, RTP/RTCP protocols and how these three protocols are related and synchronized in order to actually know what is happening during the course of call set up and media exchange between the various end callers involved. The report looks into aspects of bandwidth consumption by the exchanged media (RTP and RTCP), jitter and its variation over the duration of the calls and the cooperation between the control plane and the user plane in order for a smooth call set up, media exchange and release of network resources. The thesis focuses on the areas of interest mentioned above, as these protocols have been identified as being of high significance in media transfer during video calls over IP.

Personal network and their federations (called Fednet) are considered as one of the promising future concepts regarding the personal communication. In this thesis, we first studies the state of the art of Fednet, from which we know there are two approaches for providing the services in Fednet, one is overlay and the other is proxy-based. Each of the approaches has the advantages and drawbacks. To trade off between these two approaches, we propose a new scheme, which can make the way of service provisioning in Fednet flexible and adaptable to the changing environment and the user’s preference.

Bij evenementen, concerten en shows wordt er heel veel licht gebruikt met heel veel verschillende effecten. Bij deze effecten verandert het licht continu van kleur en intensiteit. Degene die een lichtshow regelt is de lichttechnicus en dit doet hij met een lichttafel. Lichtshows waarbij de technicus tijdens het evenement moet beslissen welk effect hij op welk moment wil laten zien, heten live lichtshows. De doelstelling van deze thesis is om een nuttige basis te presenteren voor de verdere ontwikkeling van de gebruikersinterface van de CS-2.

Communication systems evolve day after day at a very fast pace. People not only have high expectations in regard of the conversation quality, but they also need more data download speeds and better coverage. The industry tries to come and fill in this expectation by developing state-of-the art systems that are cost-effective and that ensure good profits. Telecommunication operators require from vendors top class, cheap and reliable equipments for their sites. Vendors on the other hand try to cut down costs by simulating and then developing products. The aim of this project is to simulate three important wireless systems LTE, UMTS and GSM/EDGE (at physical layer level) for base stations, according to the implementations mentioned in the 3GPP standards. The most demanding requirements have been derived in this work for each of the transceiver systems and a realistic system description has been implemented in MatLab 2008b. The tolerance to RF imperfections (DC offset, I-Q amplitude and phase mismatch, cubic nonlinearity, frequency offset, phase noise, etc.) are taken into consideration. Also implementation specific RF imperfection, like the delay and amplitude misalignment in outphasing transmitters has been considered. The RF imperfections have been considered in equal measures for both the transmitter and the receiver. The resulting study ensured a perfect calibration of the BER curves with the theoretical curves using the uncoded bits. The final system comparison in this thesis has been made only for the communication standard LTE, considering classical IQ Tx configuration, a pure outphasing transmitter and an improved efficiency outphasing Tx. This in order to investigate which concept is more tolerant to RF impairments. The parameters used in the simulations to check the system performances are: EVM, ACPR, scatter plots and BER. In conclusion, this study offers some suggestions for future research activities, related to topics like estimation, equalization, Rayleigh channels and Doppler affected Rayleigh channels.

The Third Generation Partnership Program's Long-Term Evolution Advanced (3GPP LTE-Advanced) group is developing a new standard for mobile broadband access that will meet the throughput and coverage requirements of a fourth generation cellular technology. The key goals for this evolution are increased data rate, improved spectrum efficiency, improved coverage and reduced latency. The ultimate results of these goals are significantly improving service provisioning and reduction of operator costs for different traffic scenarios. One of the main challenges faced by the developing standard is providing high throughput at the cell edge. Cell edge performance is becoming more important as cellular systems employ higher bandwidths with the same amount of transmit power and use higher carrier frequencies with infrastructure designed for lower carrier frequencies. One solution to improve coverage is to use the fixed relays to transmit data between the Base Stations and the Mobile Stations or User Equipments through multi hop communication. For this reason, relay technologies have been actively studied and considered in the standardization process of next-generation mobile broadband communication system. As a next-generation 3GPP standard, LTE-Advanced exclusively takes the relay technology into account. This thesis focuses the relay technologies for the LTE-Advanced systems and evaluates the performance of the relay-enhanced LTE-Advanced network. The approach for this work is to design several environments for LTE-Advanced networks involving relays. Incorporating the channel model from the Wireless World Initiative New Radio (WINNER) project, four environments were designed among which one environment considers no relay at all and the rest of the environments considered relay deployments. And the performances of all the environments are evaluated in terms of Symbol Error Rate (SER) versus the Signal to Noise Ratio (SNR), under several different scenarios defined in WINNER project. As an outcome, the simulation results from the simulator show that relay technologies can effectively improve service performance.

De professionele paraglider en fotograaf Leo Westerkamp is instaat de kijker dichter bij de natuur en sport te brengen dan ieder ander log en niet wendbaar apparaat. Echter door bochten, windvlagen, luchtdrukverschillen en trillingen van de motor ondervinden de beelden een ernstig stabiliteitsprobleem. Vandaar dan ook dat Featherweight de opdracht heeft gekregen om de camerabeelden zodanig te stabiliseren dat de beelden te verkopen zijn. Tijdens het ontwerpproces is er hoofdzakelijk rekening gehouden met de mogelijkheid de camerastabilisator lichtgewicht en makkelijk bestuurbaar te maken. Aan de andere kant mocht hierbij niet worden ingeleverd op de kwaliteit van de beelden. Ontwerp Om te voldoen aan de wensen van Westerkamp heeft Featherweight gekozen voor de Featherweight Professional. De Featherweight Professional bestaat uit een opzet waar de camera gestabiliseerd wordt door twee gekoppelde dc motoren. Westerkamp heeft zelf de controle om de camera ergens anders op te richten via een duimcontroller, en via de aangeraden LCD-bril is hij instaat zelf real-time te kijken waar hij de camera op heeft gefocust. De motoren worden aangestuurd door een laptop, wiens data verkregen wordt door een microcontroller (Arduino-Mega) en de positie van de duimcontroller. De Arduino-Mega is er om de data van de acceleratiemeter en gyrometer om te zetten naar de afwijkende hoeken die ontstaan zijn door stabilisatie problemen. Implementatie De data van de acceleratiemeter en gyrometer wordt via een I2C protocol naar de Arduino-Mega gestuurd. Hier wordt door gebruik te maken van een versimpelde Kalman filter de verkregen data omgezet naar het aantal graden dat de camera afwijkt van het punt waar hij op gestabiliseerd moet worden. De Arduino-Mega stuurt het op zijn beurt door naar de laptop met de RS-232 interface, waar het wordt verwerkt met MATLAB. Bij MATLAB ligt de nadruk op: - De hoeken aanpassen door de data van de duimcontroller en de Arduino Mega te combineren; - De hoeken begrenzen; - De hoeken en hoeksnelheden via een adaptieve PD regelaar om te zetten naar het gewenste koppel, waar de twee RX-64 motoren mee aangestuurd worden. Daarnaast worden de huidige beelden waar de camera opgericht staat, weergegeven via een LCD-scherm. Evaluatie Bij de evaluatie kwam naar voren dat veel van de eisen uit het programma van eisen voldaan werden, voor zover deze geïmplementeerd waren in het prototype. Het systeem is licht en compact genoeg en stabiliseert de grootste verstoringen uit het beeld. Daarnaast is het systeem makkelijk te bedienen en niet hinderlijk voor de piloot. Aanbevelingen Er wordt aanbevolen, voordat de Featherweight Professional in ontwikkeling wordt genomen, nader onderzoek te doen naar de gebruikerswensen, toepassen van een normale Kalman filter op de sensordata, en het omlaag brengen van de verwerkingstijd. Ook wordt er aangeraden om mogelijk over te stappen naar een gimbal constructie, het toepassen van een lock-functie zodat de camera altijd het gewenste object volgt, en het mogelijk toepassen van een softwarematige stabilisatie. Om Featherweight Professional op een bredere markt te verkopen, moet er onderzoek gedaan worden naar mogelijke klanten. Dit onderzoek kan gedaan worden door een gebruikersonderzoek uit te voeren op een testgroep.

Testing of Analog/Mixed-Signal (AMS) integrated circuits (ICs) has been one of the most challenging topics in the test technology community; this is because it is very time consuming and it is hard to distinguish between pass and fail as it is the case for digital circuits. For some applications, such as automotive industry, the quality requirements for AMS ICs can be as severe as zero Parts Per Million (PPM) level. This requires, in addition of optimizing test time, also test for all possible defects in the IC. Bridges and opens are the common defects considered for AMS circuits; they are analyzed in Defect Oriented Testing (DOT) flow in order to develop appropriate test program. With high/severe quality requirements new failure mechanisms have to be considered for test purposes. Investigating such defects and their impact on the quality is important especially for zero PPM level application. This thesis investigates the effect of dislocation defects for an NXP AMS IC which is an automotive product, manufactured in 140 nm technology. Dislocation defects cause leakage related failures while crossing a PN-junction of the device. It is very challenging in AMS testing to detect these defects. A schematic-based extraction methodology is proposed to extract the dislocation defects based on studying the cross-sections of different devices present in an IC. Using the proposed methodology for extraction, the defect list is limited to only 8% of the total active devices present in the IC. This is useful in guiding the failure analysis process and reducing the simulation effort considerably. These defects possess a high resistive signature and were simulated for different sets of resistance values. It was found that the detectability of these defects decreases as the resistance value is increased. Test selection algorithms such as ‘greedy’ and ‘unique detects first’ are used to obtain an optimal test set which is able to detect all the defects, including dislocation defects. The performance of both the algorithms in terms of test reduction is compared. The optimal test set obtained is used for validating the production data consisting of 1.3 million dies. The escaped ICs are diagnosed using a fault dictionary approach. The diagnosis results reveal that the current production data set does not suffer from dislocation defects. However, extra tests obtained for detecting dislocation defects can be kept for advanced technology nodes in the future, if these defects show up in the production environment.

We present new low complexity decoders for LDPC codes by improving existing methods.

The efficient use of the power budget in mobiles and small satellite applications is of primary importance because of the reduced size of the power sources. The limited power supply has to be spent wisely. In a transmitter, the power amplifier is the main consumer of that budget, which is why it has to be as efficient as possible. Unfortunately, high efficiency in power amplifiers is strongly related to non-linearities and hence distortion. However, several techniques help to improve the linearity of the power amplifier. One of the most powerful means to linearize a system is using negative feedback. In this work the analysis of a mixed-signal Cartesian feedback is carried out. Cartesian feedback offers two challenges: stability and phase shift. In a feedback system with a time delay in the loop, instability is likely to happen. Phase shift is the result of the time delay in the loop and non-linearities of the power amplifier. First a model of the mixed-signal system is proposed, and the stability of the system is analyzed. Second, a model of the phase shift is proposed, and the conditions under which it can be reduced are given. The model is implemented in the digital domain. In order to realise this a design consisting of a phase shift detector, a signal rotation and a magnitude computation was created in VHDL and then synthesized, while targeting FPGA and 90nm CMOS technology. An FPGA implementation shows a power consumption of 33.31[mW] for a total budget of 1.7[W] (1.96% of the total budget). The system reaches a 60° of phase margin with a loop gain of 10, for a bandwidth of 9.6[kHz]. The results show that it is possible to improve linearity at the expense of bandwidth when using Cartesian feedback.

FPGAs are easy and cheap to produce, a world of new possibilities is opened. One of those is in the area of reconfigurable computing. It is possible to extend normal CPUs with FPGAs for specific tasks, especially for those tasks which requires a lot of computational power. The Delft WorkBench is such a project. In this project, C-code is directly rewritten into a new piece of software and a set of hardware descriptions, suitable to program on a FPGA. In the rewritten part of the software, the computational parts are replaced by simple instructions to control the FPGA. The FPGA will run in parallel with the software and in this way, software can work up to 100 times faster. This thesis focus on the estimation of the required area of interconnect on a FPGA, depending on a given set of software metrics. These metrics are found by a special compiler, based on ELSA, and are specific for each part of C-code. With this estimation, it is possible to say, in an early stage of the whole process, if a certain part of software will fit on the FPGA. The developed model is based on a dataset from 127 kernels and is suitable for the Virtex2 and the Virtex4 platforms.