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Programmerbar signalanpassningJansson, Patrick January 2001 (has links)
<p>The data acquisition system COMET developed by Saab AB contains a unit for signal conditioning and A/D conversion, called KSM. The varieties in signal conditioning constitutes of a number of specific PBAs and maintenance as well as reconfiguration of these are complicated not to mention costly. This thesis has aimed to investigating whether the signal conditioning circuits can be replaced by a general purpose, programmable solution. If so, how can this be done? </p><p>The development has been carried out by evaluating ideas through the use of a laboratory environment and has resulted in an analog design for laboratory purpose. A reconfigurable design is the result of this thesis as an alternative to the solution used today. In the proposed design mainly digital otentiometers, switches and MUXes are used. In that way signal path and overall behaviour can be selected. Some extensions have been made in comparison to the current functionality, but additional development is necessary to make the design complete. </p><p>Future versions of the COMET system could be significantly improved by considering the result of this thesis when developing the signal conditioning circuitry.</p>
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Lågoffsetkomparator / LowoffsetcomparatorFransson, Daniel January 2002 (has links)
<p>Detecting small signals with a comparator demands that the total voltage offset is lower than the actual signal. The total offset includes the voltage offset in the comparator and the voltage offset that is created by the offset currents that flows thru the load at the comparators input. The goal with this comparator that has been developed has been that it will have a total voltage offset at maximum 500 uV. The comparator does not need to be extremely fast or does not need to operate in a big frequency area. To have all the flexibility that is needed a full custom technique is used. When the mismatch is most unfavourable the total offset is 209.24 uV which is within the goal.</p> / <p>För att kunna detektera små signalnivåer med en komparator krävs att den har en lägre total spänningsoffset än den signalnivå den skall detektera. I den totala offseten ingår dels den rena spänningsoffseten i komparatorn och dels den spänningsoffset som kommer att skapas när offsetströmmar på komparatorns ingångar går igenom den last som finns på ingången. Målet med den komparator som utvecklats har varit att den skall ha en total spänningsoffset på maximalt 500 uV. Inga direkta krav såsom att den skall vara snabb och att den skall kunna arbeta inom ett stort frekvensområde finns. För att få den flexibilitet som behövs är komparatorn konstruerad i en så kallad full custom teknik. När missanpassningen är som mest ogynnsam hamnar den totala spänningsoffseten på 209.24 uV vilket ligger inom målet med god marginal.</p>
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Kombinerad DSP- och FPGA-lösning för en bildbehandlingsapplikation / Combined DSP and FPGA solution for an imaging applicationMikaelsson, Marcus January 2002 (has links)
<p>This Master's Thesis describes the design of a new system where a digital signal processor has been added to an existing imaging system consisting of field programmable gate arrays. The new system will offer a higher degree of flexibility by considerably shortening the design time and make it possible to implement more complex algorithms than the existing ones. </p><p>The choice of system architecture and a test implementation are discussed. The test implementation consists of a program for the digital signal processor and VHDL code for one of the field programmable gate arrays. </p><p>The code for the digital signal processor was designed for testing on an evaluation board from Texas Instruments. The evaluation board is connected to a computer, which runs a Windows program to visualize the result. </p><p>The choice of algorithm has not been made yet. In the test implementation a skewing algorithm is used as an example. Two implementations of the skewing algorithm has been optimized, one fix point version and one floating point version.</p>
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HomeBT : För ett intelligentare hemWärja, David, Pettersson, Joakim January 2002 (has links)
<p>Frysar som känner av om dörren står öppen och spisar som registrerar värmeplattornas temperatur och inkopplingstid och vid fara larmar bostadsinnehavaren. De så kallade intelligenta konsumentprodukterna kommer i en snar framtid ersätta många av dagens ”dumma” apparater. Intelligensen skulle emellertid enkelt kunna kopplas till befintlig apparatur utan att något ingrepp i hårdvaran behöver göras. Baserat på en patentsökt idé av Niclas Fock på Combitech Systems har ett system konstruerats, som på ett snabbt, enkelt och kostnadseffektivt sätt möjliggör smarta produkter redan idag.</p> / <p>Cabinet freezers that can sense if the frontdooris unproperly closed and stoves registering temperature and usage time of the plates, alerting the house owner when danger occurs. These so called intelligent consumer products will in a nearby future replace many of todays ”dumb” devices. But intelligence could be applied on existing apparatus without changing its hardware. Based on a idea (pending patent) by Niclas Fock at Combitech Systems a system is designed. This system will in a rapidly, simple and cost effectively manner realise smart products already today.</p>
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TIR, design and testing of a Simple GALSBlaauwendraad, Bart January 2002 (has links)
<p>Globally-asynchronous locally-synchronous (GALS) systems may become a solution for nowadays challenges in the field of VLSI design. Fully synchronous chips are becoming not feasible anymore due to clock distribution and power consumtion problems. The value of GALS lies in combination of well know synchronous design methods and relative simple asynchronous communication channels. </p><p>The key components are the communication control ports around the synchronous modules and the stretchable clock also called a wrapper. This clock has a unbound delay and is controlled by events the asynchronous channel. </p><p>A simple GALS system consisting of a 4-bit transmitter, integrator and receiver has been designed and layouted for a 0,35 micron CMOS proces. A 4-phase bundled protocol is used with GasP FIFO's. Novel circuits has been designed to switch from the one wire asynchronous communication of the FIFO to the 4-phase of the wrapper. </p><p>The report also dicusses the challenges for manufature test on asynchronous designs. A test strategy for GALS systems is been devoloped.</p>
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Implementering av RS232-protokoll / Implementation of a RS232 protocollKarlsson, Tomas January 2002 (has links)
<p>Den här rapporten innehåller information om hur man skapar en länk mellan en dator och ett minne via en dators serieport. Ett RS232-protokoll används för att upprätthålla den här länken. För att ta hand om minnet samt upprätthålla kommunikationen med datorn har en FPGA programmerats. Intel hex8 formatet används för datan. Ett program för Windows 98 skapades också. Programmet öppnar en fil och läser tecken. Tecknen översätts till heltal som sänds till serieporten. Programmet kan också spara data till en fil. Data hämtas från minnet via serieporten.</p> / <p>This report contains information how to establish a link between a computer and a memory through the serialport of a computer. The RS232 protocol is used to establish this link. To handle the memory and the communication with the computer a FPGA has been programmed. The data is in Intel hex8 format. A program for Windows 98 were also created. The program opens a file and reads characters from it. The charcters are translated into integers which are sent to the serialport. The program can also store data, recieved from the serialport, to a file.</p>
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Investigation of PWM-controlled MOSFET with inductive loadLjunggren, Tobias January 2002 (has links)
<p>This report is the basis for a Bachelor of Science thesis in engineering done at Volvo Powertrain in Gothenburg. The problem consisted of investigating a circuit with a PWM-controlled MOSFET driving a DC-motor. </p><p>The problem was to investigate what caused the circuit to break the transistor. Finally an improvement of the circuit is designed making the MOSFET withstand the stressful conditions exposed to. </p><p>An overall description of the problems with switching an inductive load using a MOSFET as switch is done. Some methods to protect the MOSFET from failure are also discussed. Finally a discussion is held to suggest what broke the MOSFET, and an improved design is proposed.</p>
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Utvärdering av kalibreringsmetoder för modväxlande kammare / An Evaluation of Calibration Methods for Reverberation ChambersSandahl, Anna, Wilander, Maria January 2002 (has links)
<p>Vår uppgift var att praktiskt genomföra och utvärdera två kalibreringsmetoder för modväxlande kammare hos Saab Avionics AB i Linköping. En metod som Saab Avionics använder och en metod enligt europeisk civil flygstandard, EUROCAE ED- 14D kapitel 20.6. </p><p>Uppgiften löstes genom att utföra mätningar enligt de två kalibreringsmetoderna och därefter analysera mätdata i MatLab. </p><p>Vi hann med att göra Saab Avionics kalibreringsmetod i samtliga mätpunkter som krävdes för utvärderingen, men bara drygt halva kalibreringen enligt europeisk civil flygstandard. </p><p>Utifrån de mätningar vi gjort kan vi dra följande slutsatser: Båda kalibreringsmetoderna säger att Saab Avionics modväxlande kammare uppfyller respektive krav när den är olastad. </p><p>Båda metoderna säger också att kammaren inte uppfyller kraven när den är lastad. </p><p>Däremot visar Saab Avionics kalibreringsmetod inte samma resultat i alla demätpunkter vi jämfört när kammaren var lastad och den kan därför inte anses vara tillförlitlig i sin nuvarande form. Kalibreringsmetoderna kan inte anses likvärdiga som de ser ut idag. </p> / <p>Our assignment was to perform and evaluate two calibration methods for reverberation chambers at Saab Avionics AB in Linköping. One method used by Saab Avionics and one according to the standard EUROCAE ED-14D chapter 20.6. </p><p>The problem was solved by performing measurements according to the two methods and evaluating the data using MatLab. </p><p>We managed to carry out the Saab Avionics calibration method in all of the measuring points required for the evaluation, but only half of the calibration according to EUROCAE ED-14D. </p><p>From the measurements that we have performed we can draw the following conclusions: Both of the calibration methods state that the Saab Avionics reverberation chamber fulfils the requirements when it is unloaded. </p><p>Both of the methods also state that the chamber does not fulfil the requirements when it is loaded. </p><p>However the Saab Avionics calibration method does not give the same result in all of the measuring points that we compared when the chamber was loaded and it can therefore not be considered to be reliable in its present form. The calibration methods cannot be considered to be equal as they are today.</p>
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Modelling of Power Dissipation in CMOS DACs / Modellering av effektförbrukning i CMOS DA-omvandlareJörgensen, Sofie January 2002 (has links)
<p>In this master thesis work, the power dissipation in a current-steering digital- to-analog converter, DAC, has been studied. The digital as well as the analog power dissipation have been modelled in MATLAB and it is shown that the MATLAB models agrees well with simulation results from the circuit simulator (Spectre). </p><p>A case study on a DAC designed at Ericsson Microelectronics AB in Linköping has also been done. The DAC is a thermometer-coded current-steering DAC suitable for telecommunications applications. The telecommunication standards that have been studied are asymmetric digital subscriber line, ADSL, very high speed data digital subscriber line, VDSL, and, wireless local area network, WLAN. The conlusion of the study is that the power dissipation of the specific DAC, used in ADSL applications, 75mW, is far from optimized. It can theoretically be lowered to 3.5mW.</p>
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Design comparison between HiperLAN/2 and IEEE802.11a services / Design comparison between HiperLAN/2 and IEEE802.11a servicesEdbom, Emil, Henriksson, Henrik January 2001 (has links)
<p>This paper is a study and comparison between the two Wireless LAN (WLAN) standards HiperLAN/2 and IEEE 802.11a. WLANs are used instead or together with ordinary LANs to increase mobility in for example an office. HiperLAN/2 is an European standard developed by ETSI and the IEEEs standard is American. </p><p>A WLAN-card consists roughly of a Medium Access Control (MAC), Physichal layer (PHY) and an antenna. The antenna is the same for the different standards. </p><p>Both standards operates at 5.4 GHz with a maximum transmission rate at 54 Mbit/s and they use OFDM to modulate the signal. This means that the physical layer in the two standards is similar. </p><p>The differences between the standards are in the Medium Access Control (MAC) layer. HiperLAN/2 has a much more complex MAC since it is developed with the starting point in cellular phones. Therefore this MAC is not very similar to ETHERNET that is the protocol used by regular network. On the other hand it is built to be compatible with cellular phones and other applications. </p><p>The 802.11a MAC is very much the same as in the 802.11b standard that is the most used standard at present. The difference is that 802.11a can send at much higher data rates. This MAC is build with starting point in ETHERNET so it has a similar interface to the computer. This makes it less complex. </p><p>The different MACs can provide different services. The greatest difference is that 802.11a can use a distributed send mode where any STA can send if the medium is idle. This reminds a lot of ETHERNET but they use different methods to sense if the medium is idle. In HiperLAN/2 are all transmissions scheduled by the AP. 802.11a can operate in a similar way but at the moment this mode is not as fully developed as in HiperLAN/2. There are working groups in IEEE that works toward an improvement of 802.11a so it can use queues with different priorities, this is already implemented in HiperLAN/2. </p><p>Another important issue in wireless environment is security. Both standards use encryption to protect their messages. The difference is that HiperLAN/2 changes their encryption key for every connection where 802.11a uses the same key the whole time. This gives HiperLAN/2 a better security with todays standard but thereare working groups dealing with implementing key-exchange functions and Kerberos use in 802.11a. Chapter 8 is a description of a program that we developed in C++. The program is used to monitor the different registers and ports a WLAN-card use. It is written for a 802.11b card and should be used together with Windows 2000. The source code can be found in appendix C.</p>
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