• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 4
  • 1
  • 1
  • Tagged with
  • 18
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Electronical model evaluation and development of compact model including aging for InP heterojunction bipolar transistors (HBTs) / Evaluation de modèle électrique et développement d?un modèle compact incluant le vieillissement pour des transistors bipolaire à hétérojonctions (TBH) à InP

Ghosh, Sudip 20 December 2011 (has links)
Les technologies de transistors bipolaires à hétérojonctions (HBT) ont montré leur efficacité pour permettre aux circuits de traiter les grands signaux au delà de 100Gbit/s pour les réseaux optiques Ethernet. Pour assurer ce résultat, une bonne fiabilité doit être garantie. Des tests de vieillissements accélérés sous contraintes thermiques et électrothermiques sont réalisés et analysés avec les outils de simulation physique Sentaurus TCAD afin d’obtenir les lois de vieillissement physiques. Le modèle compact HICUM niveau 2, basé sur la physique, est utilisé pour modéliser précisément le composant avant vieillissement, puis pour ajuster les caractéristiques intermédiaires pendant le vieillissement. L’évolution des paramètres du modèle est décrit avec des équations appropriées pour obtenir un modèle électrique compact du vieillissement basé sur la physique. Les lois de vieillissement et les équations d’évolutions des paramètres avec le temps de contrainte sont implantées dans le modèle électrique de vieillissement en langage Verilog-A, ce qui permet de simuler l’impact des mécanismes de défaillances sur le circuit en conditions opérationnelles. / Modern InP Heterojunction Bipolar Transistors (HBT) technology has shown its efficiency for making large signal ICs working above 100 Gbits/s for Ethernet optical transport network. To full-fill this expectation, a good reliability has to be assured. Accelerated aging tests under thermal and electro-thermal stress conditions are performed and analyzed with Sentaurus TCAD device simulation tools to achieve the physical aging laws. The physics based advanced bipolar compact model HICUM Level 2 is used for precise modeling of the devices before aging. The HICUM parameters are extracted to fit the intermediate characterizations during aging. The evolution of the model parameters is described with suitable equations to achieve a physics based compact electrical aging model. The aging laws and the parameter evolution equations with stress time are implemented in compact electrical aging model in Verilog-A languages which allows us to simulate the impact of device failure mechanisms on the circuit in operating conditions.
12

Automatiserad kalibrering av väderradar / Automated Calibration of Weather Radar

Pedersson, Cecilia January 2009 (has links)
För att kalibrera väderradarna i Sverige finns en miniräknare med program som styr kalibreringen. Deluppgiften ”Program för kalibrering” innebär att överföra dessa program till en PC. Då ingen dokumentation finns om hur kommunikationen sker mellan radar och miniräknare, är första steget att analysera och jämföra programkoden från miniräknaren med informationen från en linjelyssnare. Därefter skrivs programmen i det grafiska programmeringsspråket Agilent Vee. Programmen läser av radarns svar på signaler med olika dämpning från en signalgenerator, beräknar en radarkonstant, skapar en kalibreringstabell, samt programmerar kalibreringstabellen i radarns signalprocessor. Datorns mätvärden och beräkningar jämförs med miniräknarens, och det kan konstateras att programmen överensstämmer med varandra. Deluppgiften ”Automatiserad kontroll av dämpsteg” innebär att med en spektrumanalysator läsa av effekten på en signal med varierande dämpning från en signalgenerator. Detta görs för att kontrollera dämpstegen, då man på Saab Aerotech upptäckt problem med signalgeneratorn. Ett program skrivs för att automatiskt styra både signalgenerator och spektrumanalysator. Den avlästa effekten vid varje dämpsteg sparas och en graf med dessa värden genereras automatiskt av programmet. I grafen återfås en linjär kurva, vilket är det förväntade utseendet vid fungerande dämpsteg. För en ytterligare kontroll läses effekten av vid varje enskild dämpare. Även dessa värden ligger inom accepterade gränser, vilket innebär att problemet ligger på annat håll i signalgeneratorn, än i dämpstegen. / A calculator is used to calibrate all the weather radars in Sweden. One part of this thesis is to transfer the programs on this calculator to a PC. There is no documentation on how the calculator communicates with the radar, so the first step is to analyze and compare the code from the program with the information shown on a protocol analyzer. When the communication is known, a program is written in the language Agilent Vee. One program reads the response from the radar of a signal with different attenuation. Others calculates the radar constant, generates a calibration table and programs the table to the signal processor in the radar. By comparing the result from the programs on the PC and the corresponding results from the calculator it is verified that the programs run correctly. Saab Aerotech have found that the signal generator in not working correctly. The other part of this thesis is to automatically control the signal generator and a spectrum analyzer. The spectrum analyzer reads the power of a signal with different attenuation from the signal generator and presents the values in a graph. The curve of the graph is linear which means that there is no problem with the attenuation.
13

Design av mikrovågsövergångar / Design of microwave connections

Petersson, Björn January 2003 (has links)
<p>In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. </p><p>The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured. </p><p>The main goal of this Master thesis was to design a connection, that would be useful in practice. The connections should be easy to manufacture and have a good performance. They should also have a high tolerance for manufacturing errors. </p><p>The main part of this report contains descriptions of different designs. The designs are presented together with simulated and measured results. </p><p>The report contains designs based upon coplanar waveguides and a phase shifting technique. The result shows that designs that are using coplanar waveguides are good. The phase shifting technique has some limitations and need to be developed further.</p>
14

Design av mikrovågsövergångar / Design of microwave connections

Petersson, Björn January 2003 (has links)
In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured. The main goal of this Master thesis was to design a connection, that would be useful in practice. The connections should be easy to manufacture and have a good performance. They should also have a high tolerance for manufacturing errors. The main part of this report contains descriptions of different designs. The designs are presented together with simulated and measured results. The report contains designs based upon coplanar waveguides and a phase shifting technique. The result shows that designs that are using coplanar waveguides are good. The phase shifting technique has some limitations and need to be developed further.
15

Měření impedancí s vyhodnocováním nejistot / Impedance measurement with uncertainty assessment

Fiala, Radim January 2010 (has links)
This Master’s thesis deals with standard uncertainity determination for electrical quantities measurement. Next, there are proposals of uncertainity calculation procedures for impedance measurement. Impedance is measured by LCR meter Agilent 4263B. Using the proposed procedures, standard uncertainities are then calculated. Furthermore, there is proposal for an improved laboratory exercise for the MEMT subject, implementing the standard measurement uncertainities calculations.
16

Spektroskopická impedanční měření v olověných akumulátorech / Impedance spectroscopy measurements in lead acid batteries

Holemář, Jan January 2015 (has links)
The master thesis provides a brief introduction to the lead-acid batteries. The thesis describes an internal construction, electrochemical reactions inside the batery, the area of application and possible degradation effects. The next part deals with an analytic method of the measurement called electrochemical impedance spectroscopy. The thesis describes the principle of measurement, alternative equivalent circuits, the impedance of electrochemical cell and the analyse of recorded datas. In the practical part was assembled the functional lead-acid cell. After that, experimental measurement was passed on the lead-acid cell in discharge and in a different concentration of electrolyte. In the last part was created the simulation of treatment of an electrochemical cell in the development solution Agilent VEE and after that all the measurement results were compared with the simulation.
17

Vývoj mobilních aplikací pro vzdálené ovládání přístrojové techniky / Mobile applications development for remote control of instrumentation

Macek, Michal January 2016 (has links)
The presented work describes the growing trend of using mobile devices to control laboratory instruments and displaying of measured data. The main objective is the application development for mobile devices, which will allow to remotely control and measure with laboratory instruments. The practical part is focused to programming mobile application which will be able by using the local network to connect multiple laboratory instruments, setting them for different types of measurements and then display measured data.
18

Systém Hefaistos / The Hefaistos System

Mancl, Vlastimil January 2019 (has links)
This master's thesis describes functionality and principle of the Hefaistos measurement system, which is fully automated and modular. Its purpose is to measure frequency responses of materials and its temperature dependence. The thesis describes all the necessary parts of the modular measurement system. Main part of this system is the control application programmed in LabVIEW software environment. Another necessary parts are impedance analyzers for acquiring frequency dependencies and heating chambers for heating measured materials. The control application ensures hardware synchronization between impedance analyzers and heating chambers. Together they create the Hefaistos system. Modularity of the system means that a user may choose which instrument combination will be used. The system offers choice between three impedance analyzers Agilent 4294A, Wayne Kerr 6520B and HIOKI 3532 LCR Hi-Tester and two heating chambers AOIP GEMINI 700 LRI and AOIP HYPERION. Possibilities of the Hefaistos system are demonstrated on the results of an example measurement.

Page generated in 0.0432 seconds