Within modern frequency structures, the filter frequency region of up to 10 MHz constitutes a promising research topic that currently attracts intensive attention of specialists interested in the problem. The main reason of this fact consists in that the rapid development of modern technology allows the production of innovated structures of the analog frequency filters required in the defined band. In this context, however, it is also necessary to refine the methods applied in the synthesis and optimization of these structures; such improvement should be carried out with respect to fundamental properties and usability of today's active elements (operational amplifiers with voltage feedback whose Gain Bandwidth Product ranges within units of GHz, operational amplifiers with current feedback, conveyors, transimpedance operational amplifiers). In this thesis, active blocks of synthesis inductors (SIs) and frequency dependent negative resistors (FDNRs) are examined in detail, and the author provides novel formulas to define the basic parameters of the dual circuits. Due emphasis was placed on optimizing the basic building blocks of the second order and defining the variation of their properties caused by the addition of modern active elements. The blocks were analyzed and modified in view of their possible use in higher-order circuits. For active filters of a higher order, simulations were performed to indicate the actual sensitivity of the cascade and non-cascade ARC structures. The following phase of the research comprised mainly the designing of several filters, and this activity was further completed with the verification of the methodology for the synthesis and optimization of higher-order loss ladder filters with modern active blocks. Special attention was paid also to the methods enabling the optimization of such filters, which are invariably based on RLC prototypes. In order to verify the theoretical conclusions, the author materialized a large number of sample optimized filters and measured their parameters. The closing section of the thesis describes the use of the filters in specific applications.

<p>This master thesis describes a design exploration of a circuit capable of measuring high speed signals without adding significant capacitive load to the measuring node. </p><p>It is designed in a 0.13 CMOS process with a supply voltage of 1.2 Volt. The circuit is a master and slave, track-and-hold architecture incorporated with a capacitive voltage divider and a NMOS source follower as input buffer to protect the measuring node and increase the input voltage range. </p><p>This thesis presents the implementation process and the theory needed to understand the design decisions and consideration throughout the design. The results are based on transistor level simulations performed in Cadence Spectre. </p><p>The results show that it is possible to observe the analog behaviour of a high speed signal by down converting it to a lower frequency that can be brought off-chip. The trade off between capacitive load added to the measuring node and input bandwidth of the measurment circuit is also presented.</p>

This master thesis describes a design exploration of a circuit capable of measuring high speed signals without adding significant capacitive load to the measuring node. It is designed in a 0.13 CMOS process with a supply voltage of 1.2 Volt. The circuit is a master and slave, track-and-hold architecture incorporated with a capacitive voltage divider and a NMOS source follower as input buffer to protect the measuring node and increase the input voltage range. This thesis presents the implementation process and the theory needed to understand the design decisions and consideration throughout the design. The results are based on transistor level simulations performed in Cadence Spectre. The results show that it is possible to observe the analog behaviour of a high speed signal by down converting it to a lower frequency that can be brought off-chip. The trade off between capacitive load added to the measuring node and input bandwidth of the measurment circuit is also presented.

In this thesis we address the problem of providing end-to-end quality of service (QoS) to real-time and data connections in a third generation (3G) cellular network based on the Universal Mobile Telecommunication System (UMTS) standard. Data applications usually use TCP (Transmission Control Protocol) and the QoS is a minimum guaranteed mean throughput. For this one first needs to compute the throughput of a TCP connection sending its traffic through the UMTS network (possibly also through the wired part of the Internet). Thus we obtain closed form expressions for a TCP throughput in a UMTS environment. For downloading data at a mobile terminal, the packets of each TCP connection are stored in separate queues at the base station (node B). These are fragmented into Protocol Data Units (PDU). The link layer uses ARQ (Automatic Repeat Request). Thus there can be significant random transmission/queueing delays of TCP packets at the node B. On the other hand the link may not be fully utilized due to the delays of the TCP packets in the rest of the network. In such a scenario the existing models of TCP may not be sufficient. Thus we provide new approximate models for TCP and also obtain new closed form expressions of mean window size. Using these we obtain the throughput of a TCP connection for the scenario where the queueing delays are non-negligible compared to the overall Round Trip Time (RTT) and also the link utilization is less than one. Our approximate models can be useful not only in the UMTS context but also else where. In the second half of the thesis, we use these approximate models of TCP to provide minimum mean throughput to data connections in UMTS. We also consider real-time applications such as voice and video. These can tolerate a little packet loss (~1%) but require an upper Bound on the delay and delay jitter (≤ 150 ms). Thus if the network provides a constant bandwidth and the received SINR is above a specified threshold ( with a certain probability), QoS for the real-time traffic will be satisfied. The 3G cellular systems are interference limited. Thus wise allocation of power is critical in these systems. Hence we consider the problem of providing end-to-end QoS to different users along with the minimization of the downlink power allocation.

Dans le cadre de l'amélioration des méthodes de modélisation du comportement hydraulique des moteurs à ergols liquides, il est important de disposer des méthodes d'identification expérimentale adaptées au besoin de caractérisation des fonctions de transfert des pompes en régime cavitant, notamment pour prédire les risques d'occurrence des phénomènes de couplage fluide-structure comme le Pogo. La matrice de transfert dynamique d'une pompe relie dans le domaine fréquentiel les fluctuations complexes (module + phase) de débit et de pression à l'entrée avec celles de sortie de la pompe. Par ailleurs, les mécanismes physiques qui régissent la réponse d'une pompe soumise à des fluctuations de pression et/ou de débit restent méconnus, ce qui rend aujourd'hui très difficile les prévisions théoriques. Dans le cadre des travaux développés, une nouvelle boucle d'essais a été mise en place permettant la mesure de la pression fluctuante et l'évaluation du débit fluctuant par une approche d'intensimétrie hydroacoustique. Une méthodologie d'essais a été mise en place sur le banc de test pour caractériser les fonctions de transfert de différents organes hydrauliques, notamment en régime cavitant, comme une pompe centrifuge. Ces travaux expérimentaux ont permis également d'alimenter et de valider les modèles de type " système " RLC utilisés pour la simulation du comportement acoustique du circuit. Les méthodologies d'essais, de post-traitement et de modélisation développés dans le cadre de cette thèse seront appliquées par l'industriel lors des essais dédiés sur le banc de test à des composants moteur.

This thesis deals with the synthesis and optimization of frequency analogue filters with modern active elements usable for higher frequencies. The thesis is divided into three parts, the first part deals with the problematic concerning Leap-Frog combined ARC structure. Due to a difficult design, this method is not described in a detail and used in practice, although it shows e.g. low sensitivity. Firstly, a complete analysis of individual filters was made (for and T endings) and consequently these findings were used during implementation of this method to NAF program. Finally, samples of real filters were realized (for verification of functioning and correct design). Another very interesting topic concerning filters is usage of coupled band-pass for small bandwidth, where it is necessary to solve the problems concerning ratio of building elements values, but also price, quality, size of coils, sensitivity, Q factors, coefficients etc. That is why in practice a coil is very often substituted with other equivalent lossy and lossless blocks which create ARC filters structure. The design and the possibility of usage of lossy grounded elements were described here (such as synthetic inductors, frequency dependent negative resistor). Some parts of the design are individual computer sensitivity analysis, setting of usage and quality comparison of individual lossy grounded blocks. Besides, a program for these elements was created, it is useful for a quick design and depiction of transfer characteristics. The third part deals with the usage of tuning universal filters consisting three or more operational amplifiers, which secures its universality and possibility to create different kinds of transfer characteristic. In practice, Akerberg - Mossberg and Kerwin - Huelsman - Newcomb are the most used types of filters. These were also compared with less common universal filters. In the end, the possibility of digital tuning of universal filter with the help of digital potentiometers for filters of 10th order and frequency around 1 MHz was shown.