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  • 251.
    Andersson, Niklas
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Design of Integrated Building Blocks for the Digital/Analog Interface2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Den integrerade kretsen har sedan den uppfanns i slutet av 1950-talet genomgått en enorm utveckling och återfinns idag i princip i all elektronisk utrustning. Den lilla storleken och den låga produktionskostnaden har gjort det möjligt att integrera elektronik i vardagsföremål som datorer och mobiltelefoner och enklare system som till exempel smarta etiketter. Typiska användningsområden för integrerade kretsar är datakommunikation, signalbehandling och datalagring. Data lagras vanligtvis i digitalt format men signalbehandling kan utföras i både den digitala och i den analoga domänen. För att nå bästa prestanda i en krets måste signalbehandlingen delas upp optimalt mellan den digitala och analoga domänen Denna uppdelning möjliggörs med hjälp av dataomvandlare som översätter data mellan de två domänerna. En krets som omvandlar en analog signal till en digital motsvarighet kallas för en analogtill-digital-omvandlare och en krets som ovandlar digitalt data till en analog signal kallas för en digital-till-analog-omvandlare. Denna doktorsavhandling innehåller resultat från forskning gjord på dessa dataomvandlare och resultaten är sammanfattade i tre huvudkategorier. Det första bidraget är en felkorrigeringsmetod för digitaltill-analog-omvandlare, det andra bidraget är en kretsarkitektur för en energieffektiv tid-till-digital-omvandlare och det tredje bidraget är en konstruktionsmetodik för frekvenssyntes med hjälp av digitala svängningskretsar.

    Noggrannheten hos en dataomvandlare, med andra ord hur noggrannt dataomvandlaren kan omvandla data mellan de två domänerna, begränsas ofta av de fel som uppstår vid tillverkningen av den integrerade kretsen. En typ av fel som uppstår är att dataomvandlarens jämförelsenivåer inte blir lika stora. I frekvensdomänen kommer denna typ av fel resultera i icke önskade harmoniska frekvenser (distorsion) som begränsar dataomvandlarens noggrannhet. Om distorsion, som uppkommer då ett fel beror på dataomvandlarens insignal, begränsar dataomvandlarens prestanda kan den föreslagna felkorrigeringsmetoden omvandla distortionen till brus genom att göra felet oberoende av insignalen. Det resulterande bruset kan sedan formas spektralt eller filteras bort och därmed öka systemets totala prestanda. Den föreslagna korrigeringsmetiden har undersökts teoretiskt och denna teori har sedan verifierats med mätresultat från en kretsimplementation av en 14-bitars digital-till-analog-omvandlare som använder den föreslagna felkorrigeringsmetoden. Mätresultaten visar att metod en höjer prestandan hos dataomvandlaren för låga insignalfrekvenser då det är felen i jämförelsenivåerna som begränsar prestandan. Vid högre insignalfrekvenser är metoden mindre effektiv då andra dynamiska felkällor hos dataomvandlaren istället begränsar noggranheten.

    Nästa bidrag är en kretsarkitektur till en tid-till-digital-omvandlare. En tid-tilldigital-omvandlare är en särskild sorts analog-till-digital-omvandlare som omvandlar tidsskillanden mellan två signaler till en digital representation. Mätresultat från en kretsprototyp visar att den föreslagna kretsarkitekturen är både mindre och mer energieffektiv än tidigare publicerade kretslösningar.

    Det tredje bidraget är en konstruktionsmetodik för frekvenssyntes med hjälp av digitala svängningskretsar (oscillatorer). De digitala oscillatorerna genererar en sinusformad utsignal med hjälp av rekursiva algoritmer. Vi visar att prestandan hos digitala oscillatorer, mätt i termer av amplitud- och frekvensstabilitet, till stor utsträckning beror av starttillstånden hos oscillatorerna. Vi visar också att en del starttillstånd tvingar en oscillator att upprepa samma utsignalssekvens om och om igen, vi har då fått vad vi kallar en låst oscillator. Om oscillatorn har låst finns det inte längre någon drift i amplitud eller frekvens vilka är vanliga problem för rekursiva oscillatorer som inte använder denna metod. För att hitta de op timala startvillkoren för oscillatorerna har en sökalgoritm utvecklats. Denna algoritm har testats noggrannt i datorsimuleringar. En digital oscillator är lämplig att användas för testsignalgenerering för digital-tillanalog-omvandlare där kraven på amplitud- och frekvensstabila testsignaler är höga.

    Delarbeten
    1. A comparison of dynamic element matching in DACs
    Öppna denna publikation i ny flik eller fönster >>A comparison of dynamic element matching in DACs
    1999 (Engelska)Ingår i: Proceedings '99 : Oslo, Norway, 8-9 November 1999 / [ed] Trond Sæther, 1999, s. 385-390Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
    Abstract [en]

    In the field of dynamic element matching, DEM, techniques, some "new" important theoretical results have been presented during the last decade. However, no comparison between these different DEM techniques (FRDEM, PRDEM, NSDEM) used in wideband digital-to-analog converters, DACs, has been reported. A brief review of different DEM techniques and a comparison between their properties in terms of complexity, etc., are presented in this paper together with simulation results showing the impact of using different DEM techniques.

    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112582 (URN)8798263722 (ISBN)
    Konferens
    The 17th NORCHIP Conference, November 8-9, Oslo, Norway
    Tillgänglig från: 2014-12-04 Skapad: 2014-12-04 Senast uppdaterad: 2018-11-08Bibliografiskt granskad
    2. A strategy for implementing dynamic element matching in current-steering DACs
    Öppna denna publikation i ny flik eller fönster >>A strategy for implementing dynamic element matching in current-steering DACs
    2000 (Engelska)Ingår i: Mixed-Signal Design, 2000. SSMSD. 2000 Southwest Symposium on, IEEE , 2000, s. 51-56Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
    Abstract [en]

    Interesting comparisons of dynamic element matching (DEM) techniques, have been presented during the last decade. However, not many chip implementations of these DEM techniques have been presented so far. A brief review of different DEM techniques are presented in this paper together with a strategy for implementing the partial randomization DEM, PRDEM, technique in a 3.3 V supply, 14 bit CMOS current-steering wideband digital-to-analog converter (DAC)

    Ort, förlag, år, upplaga, sidor
    IEEE, 2000
    Nyckelord
    0.35 micron;11 MHz;14 bit;3.3 V;88 MHz;CMOS wideband DAC;current-steering DACs;dynamic element matching;partial randomization technique;wideband digital-to-analog converter;CMOS integrated circuits;digital-analogue conversion;
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-70637 (URN)10.1109/SSMSD.2000.836445 (DOI)0-7803-5975-5 (ISBN)
    Konferens
    SSMSD 2000, 27 - 29 Feb. 2000, San Diego, CA , USA
    Tillgänglig från: 2011-09-14 Skapad: 2011-09-14 Senast uppdaterad: 2018-11-08
    3. Models and Implementation of a Dynamic Element Matching DAC
    Öppna denna publikation i ny flik eller fönster >>Models and Implementation of a Dynamic Element Matching DAC
    2003 (Engelska)Ingår i: Analog Integrated Circuits and Signal Processing, ISSN 0925-1030, E-ISSN 1573-1979, Vol. 34, nr 1, s. 7-16Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The dynamic element matching (DEM) techniques for digital-to-analog converters (DACs) has been suggested as a promising method to improve matching between the DAC''s reference levels. However, no work has so far taken the dynamic effects that limit the performance for higher frequenciesinto account. In this paper we present a model describing the dynamic properties of a DEM DAC and compare the simulated results with measurements of a 14-bit current-steering DEM DAC implemented in a 0.35-μm CMOS process. The measured data agrees well with the results predicted by the used model. It is also shown that the DEM technique does not necessarily increase the performance of a DAC when dynamic errors are dominating the achievable performance.

    Ort, förlag, år, upplaga, sidor
    Netherlands: Springer, 2003
    Nyckelord
    DAC, DEM, CMOS, matching, current-steering
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-21845 (URN)10.1023/A:1020331415597 (DOI)
    Tillgänglig från: 2009-10-06 Skapad: 2009-10-06 Senast uppdaterad: 2017-12-13
    4. A Vernier Time-to-Digital Converter With Delay Latch Chain Architecture
    Öppna denna publikation i ny flik eller fönster >>A Vernier Time-to-Digital Converter With Delay Latch Chain Architecture
    2014 (Engelska)Ingår i: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 61, nr 10, s. 773-777Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A new Vernier time-to-digital converter (TDC) architecture using a delay line and a chain of delay latches is proposed. The delay latches replace the functionality of one delay chain and the sample register commonly found in Vernier converters, hereby enabling power and hardware efficiency improvements. The delay latches can be implemented using either standard or full custom cells, allowing the architecture to be implemented in field-programmable gate arrays, digital synthesized application-specific integrated circuits, or in full custom design flows. To demonstrate the proposed concept, a 7-bit Vernier TDC has been implemented in a standard 65-nm CMOS process with an active core size of 33 mu m x 120 mu m. The time resolution is 5.7 ps with a power consumption of 1.75 mW measured at a conversion rate of 100 MS/s.

    Ort, förlag, år, upplaga, sidor
    Institute of Electrical and Electronics Engineers (IEEE), 2014
    Nyckelord
    CMOS; delay latch; time-to-digital converter (TDC); Vernier
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112180 (URN)10.1109/TCSII.2014.2345289 (DOI)000343320500009 ()
    Tillgänglig från: 2014-11-18 Skapad: 2014-11-18 Senast uppdaterad: 2017-12-05
    5. Power-efficient time-to-digital converter for all-digital frequency locked loops
    Öppna denna publikation i ny flik eller fönster >>Power-efficient time-to-digital converter for all-digital frequency locked loops
    2015 (Engelska)Ingår i: 2015 EUROPEAN CONFERENCE ON CIRCUIT THEORY AND DESIGN (ECCTD), Institute of Electrical and Electronics Engineers (IEEE), 2015, s. 300-303Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    An 8-bit time-to-digital converter (TDC) for all-digital frequency-locked loops ispresented. The selected architecture uses a Vernier delay line where the commonlyused D flip-flops are replaced with a single enable transistor in the delay elements.This architecture allows for an area efficient and power efficient implementation. Thetarget application for the TDC is an all-digital frequency-locked loop which is alsooverviewed in the paper. A prototype chip has been implemented in a 65 nm CMOSprocess with an active core area of 75μmˆ120μm. The time resolution is 5.7 ps with apower consumption of 1.85 mW measured at 50 MHz sampling frequency.

    Ort, förlag, år, upplaga, sidor
    Institute of Electrical and Electronics Engineers (IEEE), 2015
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112589 (URN)10.1109/ECCTD.2015.7300008 (DOI)000380498200010 ()978-1-4799-9877-7 (ISBN)
    Konferens
    European Conference on Circuit Theory and Design (ECCTD)
    Tillgänglig från: 2014-12-04 Skapad: 2014-12-04 Senast uppdaterad: 2019-01-07Bibliografiskt granskad
    6. Steady-state cycles in digital oscillators
    Öppna denna publikation i ny flik eller fönster >>Steady-state cycles in digital oscillators
    2014 (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Digital recursive oscillators locked in steady-state can be used to generate sinusoids with high spectral purity. The locking occurs when the oscillator returns to a previously visited state and repeats its sequence. In this work we propose a new search algorithm and two new search strategies to find all steady-states for a given oscillator configuration. The improvement in spurious-free dynamic range is between 7 and 40 dB compared to previously reported results. The algorithm is also able to find oscillator sequences for more frequencies than previously reported work. A key part of the method is the reduction of the search space made possible by a proposed extension of existing theory on recursive oscillators. Specific properties of digital oscillators in a steady-state are also discussed. It is shown that the initial states can be used to individually control the phase, amplitude, spectral purity, and also cycle length of the oscillator output.

    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:liu:diva-112590 (URN)
    Tillgänglig från: 2014-12-04 Skapad: 2014-12-04 Senast uppdaterad: 2018-11-08Bibliografiskt granskad
  • 252.
    Andersson, Niklas
    et al.
    Ericsson Microelectronics AB.
    Andersson, Ola
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Models and Implementation of a Dynamic Element Matching DAC2003Ingår i: Analog Integrated Circuits and Signal Processing, ISSN 0925-1030, E-ISSN 1573-1979, Vol. 34, nr 1, s. 7-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic element matching (DEM) techniques for digital-to-analog converters (DACs) has been suggested as a promising method to improve matching between the DAC''s reference levels. However, no work has so far taken the dynamic effects that limit the performance for higher frequenciesinto account. In this paper we present a model describing the dynamic properties of a DEM DAC and compare the simulated results with measurements of a 14-bit current-steering DEM DAC implemented in a 0.35-μm CMOS process. The measured data agrees well with the results predicted by the used model. It is also shown that the DEM technique does not necessarily increase the performance of a DAC when dynamic errors are dominating the achievable performance.

  • 253.
    Andersson, Niklas
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniska Kretsar och System. Linköpings universitet, Tekniska högskolan.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniska Kretsar och System. Linköpings universitet, Tekniska högskolan.
    A Vernier Time-to-Digital Converter With Delay Latch Chain Architecture2014Ingår i: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, E-ISSN 1558-3791, Vol. 61, nr 10, s. 773-777Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new Vernier time-to-digital converter (TDC) architecture using a delay line and a chain of delay latches is proposed. The delay latches replace the functionality of one delay chain and the sample register commonly found in Vernier converters, hereby enabling power and hardware efficiency improvements. The delay latches can be implemented using either standard or full custom cells, allowing the architecture to be implemented in field-programmable gate arrays, digital synthesized application-specific integrated circuits, or in full custom design flows. To demonstrate the proposed concept, a 7-bit Vernier TDC has been implemented in a standard 65-nm CMOS process with an active core size of 33 mu m x 120 mu m. The time resolution is 5.7 ps with a power consumption of 1.75 mW measured at a conversion rate of 100 MS/s.

  • 254.
    Andersson, Niklas
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Power-efficient time-to-digital converter for all-digital frequency locked loops2015Ingår i: 2015 EUROPEAN CONFERENCE ON CIRCUIT THEORY AND DESIGN (ECCTD), Institute of Electrical and Electronics Engineers (IEEE), 2015, s. 300-303Konferensbidrag (Refereegranskat)
    Abstract [en]

    An 8-bit time-to-digital converter (TDC) for all-digital frequency-locked loops ispresented. The selected architecture uses a Vernier delay line where the commonlyused D flip-flops are replaced with a single enable transistor in the delay elements.This architecture allows for an area efficient and power efficient implementation. Thetarget application for the TDC is an all-digital frequency-locked loop which is alsooverviewed in the paper. A prototype chip has been implemented in a 65 nm CMOSprocess with an active core area of 75μmˆ120μm. The time resolution is 5.7 ps with apower consumption of 1.85 mW measured at 50 MHz sampling frequency.

  • 255.
    Andersson, Niklas
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oskar
    Linköpings universitet, Institutionen för systemteknik, Datorteknik. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Steady-state cycles in digital oscillators2014Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Digital recursive oscillators locked in steady-state can be used to generate sinusoids with high spectral purity. The locking occurs when the oscillator returns to a previously visited state and repeats its sequence. In this work we propose a new search algorithm and two new search strategies to find all steady-states for a given oscillator configuration. The improvement in spurious-free dynamic range is between 7 and 40 dB compared to previously reported results. The algorithm is also able to find oscillator sequences for more frequencies than previously reported work. A key part of the method is the reduction of the search space made possible by a proposed extension of existing theory on recursive oscillators. Specific properties of digital oscillators in a steady-state are also discussed. It is shown that the initial states can be used to individually control the phase, amplitude, spectral purity, and also cycle length of the oscillator output.

  • 256.
    Andersson, Niklas
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Rudberg, Mikael
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Improvement of segmented DACs (Swedish pat. 0001917-4)2000Patent (Övrig (populärvetenskap, debatt, mm))
  • 257.
    Andersson, Niklas
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A comparison of dynamic element matching in DACs1999Ingår i: Proceedings '99 : Oslo, Norway, 8-9 November 1999 / [ed] Trond Sæther, 1999, s. 385-390Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In the field of dynamic element matching, DEM, techniques, some "new" important theoretical results have been presented during the last decade. However, no comparison between these different DEM techniques (FRDEM, PRDEM, NSDEM) used in wideband digital-to-analog converters, DACs, has been reported. A brief review of different DEM techniques and a comparison between their properties in terms of complexity, etc., are presented in this paper together with simulation results showing the impact of using different DEM techniques.

  • 258.
    Andersson, Niklas
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A strategy for implementing dynamic element matching in current-steering DACs2000Ingår i: Mixed-Signal Design, 2000. SSMSD. 2000 Southwest Symposium on, IEEE , 2000, s. 51-56Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Interesting comparisons of dynamic element matching (DEM) techniques, have been presented during the last decade. However, not many chip implementations of these DEM techniques have been presented so far. A brief review of different DEM techniques are presented in this paper together with a strategy for implementing the partial randomization DEM, PRDEM, technique in a 3.3 V supply, 14 bit CMOS current-steering wideband digital-to-analog converter (DAC)

  • 259.
    Andersson, Niklas
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Comparison of Different Dynamic Element Matching Techniques for Wideband CMOS DACs1999Ingår i: Proceedings of the 17th Norchip Conference, 1999Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In the field of dynamic element matching, DEM, techniques, some ”new” important theoretical results have been presented during the last decade. However, no comparison between these different DEM techniques (FRDEM, PRDEM, NSDEM) used in wideband digital-to-analog converters, DACs, has been reported. A brief review of different DEM techniques and a comparison between their properties in terms of complexity, etc., are presented in this paper together with simulation results showing the impact of using different DEM techniques.

  • 260.
    Andersson, Ola
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Modeling and Implementation of Current-Steering Digital-to-Analog Converters2005Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Data converters, i.e., analog-to-digital converters (ADCs) and digital-to-analog converters (DACs), are interface circuits between the analog and digital domains. They are used in, e.g., digital audio applications, data communication applications, and other types of applications where conversion between analog and digital signal representation is required. This work covers different aspects related to modeling, error correction, and implementation of DACs for communication applications where the requirements on the circuits in terms of speed and linearity are hard. The DAC architecture considered in this work is the current-steering DAC, which is the most commonly used architecture for high-speed applications.

    Transistor-level simulation of complex circuits using accurate transistor models require long simulation times. A transistor-level model of a DAC used in a system simulation is likely to be a severe bottleneck limiting the overall system simulation speed. Moreover, investigations of stochastic parameter variations require multiple simulation runs with different parameter values making transistor-level models unsuitable. Therefore, there is a need for behavioral-level models with reasonably short simulation times. Behavioral-level models can also be used to find the requirements on different building blocks on high abstraction levels, enabling the use of efficient topdown design methodologies. Models of different nonideal properties in current-steering DACs are used and developed in this work.

    Static errors typically dominates the low-frequency behavior of the DAC. One of the limiting factors for the static linearity of a current-steering DAC is mismatch between current sources. A well-known model of this problem is used extensively in this work for evaluation of different ideas and techniques for linearity enhancement. The highfrequency behavior of the DAC is typically dominated by dynamic errors. Models oftwo types of dynamic errors are developed in this work. These are the dynamic errors caused by parasitic capacitance in wires and transistors and glitches caused by asymmetry in the settling behavior of a current source.

    The encoding used for the digital control word in a current steering DAC has a large influence on the circuit performance, e.g., in terms static linearity and glitches. In this work, two DAC architectures are developed. These are denoted the decomposed and partially decomposed architectures and utilize encoding strategies aiming at a high circuit performance by avoiding unnecessary switching of current sources. The developed architectures are compared with the well-known binary-weighted and segmented architectures using behavioral-level simulations.

    It can be hard to meet a DAC design specification using a straightforward implementation. Techniques for compensation of errors that can be applied to improve the DAC linearity are studied. The well-known dynamic element matching (DEM) techniques are used for transforming spurious tones caused by matching errors into white or shaped noise. An overview of these techniques are given in this work and a DEM technique for the decomposed DAC architecture is developed. In DS modulation, feedback of the quantization error is utilized to spectrally shape the quantization noise to reduce its power within the signal band. A technique based on this principle is developed for spectral shaping of DAC nonlinearity errors utilizing a DAC model in a feedback loop. Two examples of utilization of the technique are given.

    Four different current-steering DACs implemented in CMOS technology are developed to enable comparison between behavioral-level simulations and measurements on actual implementations and to provide platforms for evaluation of different techniques for linearity improvement. For example, a 14-bit DEM DAC is implemented and measurement results are compared with simulation results. A good agreement between measured and simulated results is obtained. Moreover, a configurable 12-bit DAC capable of operating with different degrees of segmentation and decomposition is implemented to evaluate the proposed decomposed architecture. Measurement results agree with results from behavioral-level simulations and indicate that the decomposed architecture is a viable alternative to the commonly used segmented architecture.

  • 261.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Andersson, Niklas
    n/a.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A 14-Bit dual current-steering DAC2003Ingår i: Proc. Swedish System-on-Chip Conf., SSoCC'03, 2003Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A 14-bit dual current-steering digital-to-analog converter implemented in a 0.25 µm CMOS process is presented in this work. Both implementation issues and measurement results are presented. The measured spurious-free dynamic range is higher than 73 dB for signal frequencies up to 3 MHz, and a measured multi-tone power ratio of approximately 71 dB is reported for an ADSL-like input.

  • 262.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Andersson, Niklas
    n/a.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A differential DAC architecture with variable common-mode level2002Ingår i: Proc. 2002 IEEE Int. Symp. on Circuits and Systems, ISCAS'02, 2002, s. I-113-I-116Konferensbidrag (Refereegranskat)
    Abstract [en]

    A differential current-steering digital-to-analog converter (DAC) architecture allowing the common-mode level of the input signal to be varied is presented. Simulation results with models of different DAC nonlinearities indicate that the proposed architecture has a potential of improving the linearity of the converters.

  • 263.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Andersson, Niklas
    n/a.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A method of segmenting digital-to-analog converters2003Ingår i: Proc. IEEE Southwest Symposium on Mixed-Signal Design, SSMSD'03, 2003, s. 32-37Konferensbidrag (Refereegranskat)
    Abstract [en]

    Segmented architectures are often used in digital-to-analog converters (DACs). Here we propose a DAC structure based on recursive decomposition of an N-bit binary DAC into two (N-1) bit DACs and one 1 bit DAC. A DAC model that includes matching errors has been simulated. The simulation results indicate that by using four layers of decomposition it is possible to achieve similar performance as when using seven bits of traditional segmentation.

  • 264.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Andersson, Niklas
    n/a.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Combining DACs for improved performance2002Ingår i: Proc. 4th IEE Int. Conf. on Advanced A/D and D/A Conversion Techniques and their Applications, ADDA'02, 2002Konferensbidrag (Refereegranskat)
    Abstract [en]

    This work is an overview of recently proposed methods on combining DACs in order to improve performance. Some further development of these techniques are also presented. The techniques aim at reducing glitches and sensitivity towards limited output impedance in current sources.

  • 265.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Andersson, Niklas
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Spectral shaping of DAC nonlinearity errors through modulation of expected errors2001Ingår i: Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on, IEEE , 2001, Vol. 3, s. 417-420Konferensbidrag (Refereegranskat)
    Abstract [en]

    Traditionally, delta-sigma modulation has been used for shaping of quantization noise. We present a modified version of delta-sigma modulation which also takes into account unwanted nonlinearities by feeding back not only the quantization error, but also the expected physical error. Behavioral-level simulations of a 5th-order structure showing an improvement of up to 4 effective bits are included

  • 266.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    A parameterized cell-based design approach for digital-to-analog converters2004Ingår i: Proc. IEEE Int. Workshop on System-on-Chip for Real-Time Applications, IWSOC'04, 2004, s. 225-228Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to the lack of proper design automation tools, designers are often forced to use full-custom design methodologies when designing analog and mixed-signal circuits. In this work, we discuss a design methodology based on parameterized cells intended for efficient design. The methodology is illustrated with the design of a 12-bit configurable current-steering DAC. Because the cells are parameterized, their layout must be described in a generalized way, resulting in a longer design time compared with a manual layout of a fixed circuit. However, the parameterized approach simplifies iteration of the layout process and block reuse.

  • 267.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik.
    A testbed for different codes in digital-to-analog converters2004Ingår i: Proc. Swedish System-on-Chip Conf. 2004, SSoCC'04, 2004Konferensbidrag (Övrigt vetenskapligt)
  • 268.
    Andersson, Ola
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Vesterbacka, Mark
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    A yield-enhancement strategy for binary-weighted DACs2005Ingår i: Proc. European Conf. Circuit Theory and Design 2005, ECCTD'05, 2005, , s. 55-58s. 55-58Konferensbidrag (Refereegranskat)
    Abstract [en]

    One of the major contributors to the static nonlinearity of a current-steering digital-to-analog converter (DAC) is mismatch between current sources. A technique for enhancing the yield of binary-weighted current-steering DACs is proposed. The technique utilizes a special case of a general technique for spectral shaping of DAC nonlinearity errors presented earlier and requires oversampling. The technique relies on two DAC models with low computational complexity that can be integrated with the DAC at a negligible cost in terms of area and power consumption. Behavioral-level simulation results indicate that the proposed method has a good potential of enhancing the yield of binary-weighted DACs for situations where the matching errors constitute the dominating source of nonlinearity.

  • 269.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Dynamic element matching in decomposed digital-to-analog converters2004Ingår i: Proc. IEEE NORCHIP'04, Denmark: TechnoData A/S , 2004, , s. 187-190s. 187-190Konferensbidrag (Refereegranskat)
    Abstract [en]

    A dynamic element matching (DEM) technique is proposed that aims at improving the spurious-free dynamic range (SFDR) of current-steering digital-to-analog converters (DACs) implemented with a decomposed architecture. The architecture consists of a number of small binary-weighted DACs that are controlled such that only a minimum number of unit current sources are switching for the most critical code transitions. The DEM is obtained by scrambling bit pairs with equal weight. In contrast to most other DEM techniques, the scrambling is performed conditionally so that the number of switching current sources does not increase compared with the unscrambled case. Hence, the good glitch properties of the decomposed converter architecture are maintained. Simulations on a behavioral level of some decomposed DACs have been performed. Assuming random uncorrelated matching errors with Gaussian distribution and a 5% standard deviation, the SFDR value giving 90% yield is increased with 5.6 dB for a 14-bit DAC using scrambling of the two bit pairs with the largest weights. The hardware cost for the required scrambling circuits should be low since only two pairs of bits are scrambled.

  • 270. Andersson, Ola
    et al.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Modeling of glitches due to rise/fall asymmetry in current-steering digital-to-analog converters2005Ingår i: IEEE Transactions on Circuits and Systems I: Regular Papers, ISSN 1549-8328, Vol. 52, nr 11, s. 2265-2275Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current-steering digital-to-analog converter (DAC) is the most common type of DAC for high-speed applications. Glitches present in the DAC output contribute to nonlinear distortion in the DAC transfer characteristics degrading the circuit performance. One source of glitches is asymmetry in the settling behavior when switching on and off a current source. A behavioral-level model of this nonideal behavior is derived in this work. Further, a method with low computational complexity for estimating the influence of the modeled errors in the frequency domain is developed. This method can be utilized by circuit designers to derive circuit requirements for fulfilling a given frequency-domain specification, potentially relaxing the requirements compared with a worst-case analysis. Examples of model utilization are given in terms of an analytical examination and MATLAB simulations. A good agreement between simulated and analytical results is obtained.

  • 271.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik.
    Vesterbacka, Mark
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Partial decomposition of digital-to-analog converters2004Ingår i: Proc. 12th IEEE Mediterranean Electrotechnical Conf., MELECON'04, 2004, s. 193-196Konferensbidrag (Refereegranskat)
    Abstract [en]

    The decomposed DAC architecture was recently proposed as an alternative to the traditional segmented architecture. In this work, we present a modified version of the decomposed architecture with reduced hardware complexity denoted the partially decomposed architecture. Behavioral-level simulations indicate that the partially decomposed architecture is a good alternative for signals with Gaussian distribution, whereas the original decomposed or segmented architectures are preferred for sinusoidal signals.

  • 272.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Characterization of a CMOS current-steering DAC using state-space models2000Ingår i: Circuits and Systems, 2000. Proceedings of the 43rd IEEE Midwest Symposium on, IEEE , 2000, Vol. 2, s. 668-671 vol.2Konferensbidrag (Refereegranskat)
    Abstract [en]

    Performance limitations on current-steering digital-to-analog converters (DACs) are due to finite output impedances, nonideal switches, parasitic capacitances, matching, etc. In this work we present a dynamic state-space model of a 14-bit current-steering DAC which includes dynamic nonidealities. Simulation results are presented and compared to measurement results. The model can be used for fast performance estimation of D/A converters

  • 273.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem.
    Digital-to-analog converter having error correction (US pat. 6946983)2002Patent (Övrig (populärvetenskap, debatt, mm))
  • 274.
    Andersson, Ola
    et al.
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Wikner, Jacob
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Modeling of the Influence of Graded Element Matching Errors in CMOS Current-Steering DACs1999Ingår i: Proceedings of the 17th Norchip Conference, 1999Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In analog and mixed-mode circuits the matching between circuit elements is crucial.For example, in binary encoded digital-to-analog converters (DACs) the matchingbetween different bit weights can set the limit on the performance. Related to earlier workmodeling the influence of stochastic matching, the influence of graded element matching errorson the performance of current-steering DACs is shown. Presented are calculated results thatcorrelate very well with simulated results. As performance measures we use both static measuresas DNL and INL as well as frequency domain parameters as SNDR and SFDR. This discussioncan also be applied to other DAC structures, for example switched-capacitor.

  • 275.
    Andersson, Olov
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Ljungqvist, Oskar
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Tiger, Mattias
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Axehill, Daniel
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    Heintz, Fredrik
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Receding-Horizon Lattice-based Motion Planning with Dynamic Obstacle Avoidance2018Ingår i: 2018 IEEE Conference on Decision and Control (CDC), Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 4467-4474Konferensbidrag (Refereegranskat)
    Abstract [en]

    A key requirement of autonomous vehicles is the capability to safely navigate in their environment. However, outside of controlled environments, safe navigation is a very difficult problem. In particular, the real-world often contains both complex 3D structure, and dynamic obstacles such as people or other vehicles. Dynamic obstacles are particularly challenging, as a principled solution requires planning trajectories with regard to both vehicle dynamics, and the motion of the obstacles. Additionally, the real-time requirements imposed by obstacle motion, coupled with real-world computational limitations, make classical optimality and completeness guarantees difficult to satisfy. We present a unified optimization-based motion planning and control solution, that can navigate in the presence of both static and dynamic obstacles. By combining optimal and receding-horizon control, with temporal multi-resolution lattices, we can precompute optimal motion primitives, and allow real-time planning of physically-feasible trajectories in complex environments with dynamic obstacles. We demonstrate the framework by solving difficult indoor 3D quadcopter navigation scenarios, where it is necessary to plan in time. Including waiting on, and taking detours around, the motions of other people and quadcopters.

  • 276.
    Andersson, Olov
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Wzorek, Mariusz
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Rudol, Piotr
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Doherty, Patrick
    Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
    Model-Predictive Control with Stochastic Collision Avoidance using Bayesian Policy Optimization2016Ingår i: IEEE International Conference on Robotics and Automation (ICRA), 2016, Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 4597-4604Konferensbidrag (Refereegranskat)
    Abstract [en]

    Robots are increasingly expected to move out of the controlled environment of research labs and into populated streets and workplaces. Collision avoidance in such cluttered and dynamic environments is of increasing importance as robots gain more autonomy. However, efficient avoidance is fundamentally difficult since computing safe trajectories may require considering both dynamics and uncertainty. While heuristics are often used in practice, we take a holistic stochastic trajectory optimization perspective that merges both collision avoidance and control. We examine dynamic obstacles moving without prior coordination, like pedestrians or vehicles. We find that common stochastic simplifications lead to poor approximations when obstacle behavior is difficult to predict. We instead compute efficient approximations by drawing upon techniques from machine learning. We propose to combine policy search with model-predictive control. This allows us to use recent fast constrained model-predictive control solvers, while gaining the stochastic properties of policy-based methods. We exploit recent advances in Bayesian optimization to efficiently solve the resulting probabilistically-constrained policy optimization problems. Finally, we present a real-time implementation of an obstacle avoiding controller for a quadcopter. We demonstrate the results in simulation as well as with real flight experiments.

  • 277.
    Andersson, Oscar
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling.
    Energikombinat i Halmstads fjärrvärmesystem2007Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [sv]

    Klimatförändringar börjar allt mer få en viktig roll i allas vardag och för energibranschen har arbetet med att minska miljöpåverkan bara börjat. Branschen har sedan en tid tillbaka premierat fjärrvärme som bra miljöval för uppvärmningskälla för bostäder och lokaler. Faktum kvarstår dock att beroende på hur fjärrvärmesystemet ser ut så påverkar näten miljön olika. I denna rapport behandlas det lokala energibolaget Halmstads Energi och Miljös fjärrvärmesystem genom en optimering av systemkostnaden. Utifrån optimeringen studeras sedan skuggpriser, drift och miljöpåverkan för systemet. Studien behandlar även de stora fördelarna med att energibolaget samarbetar med en eventuellt kommande energikrävande industrier, i detta fall en etanolfabrik. I och med samarbetet bildas ett energikombinat där fjärrvärme, el och etanol tillverkas.

    För analysen används ett energisystemperspektiv som får större geografiska gränser än bara Halmstad. Undersökningen av systemet görs med hjälp av datorprogrammet MODEST som är ett energioptimeringsprogram som utvecklats på Linköpings Tekniska högskola. Modellen av Halmstads fjärrvärmenät baseras och valideras mot driftsäsongen 2005 och har visat sig stämma med verkligheten bra.

    Resultatet visar att Halmstad Energi och Miljö planerade effekthöjningar används fullt ut men att det nätet kommer få stora effekttoppar inom en snar framtid. Energikombinatet som analyseras visar sig både ha ekonomiska som miljöfördelar för både energibolaget och en etanolfabrik. Spillvärmen som kan utvinnas kan även den minska användningen av topplastanläggningarna i fjärrvärmenätet.

  • 278.
    Andersson, Per
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska fakulteten.
    Comparison of two Exhaust Manifold Pressure Estimation Methods2001Konferensbidrag (Refereegranskat)
    Abstract [en]

    In turbocharged engines with wastegate the exhaust pressure can change rapidly. Two methods to estimate the exhaust manifold pressure are compared for diagnosis of wastegate and turbocharger of a spark-ignited engine. One relies on the first law of thermodynamics and produces changes in exhaust manifold pressure. The second uses a model of the mass of remaining exhaust gases in the cylinder and results in absolute estimations of the exhaust manifold pressure. They does not require any extra sensors in the exhaust system after the calibration. Estimates of the exhaust manifold pressure relies on information from an air-to-cylinder observer and a static map. The exhaust manifold pressure estimators are compared using a series of wastegate steps on a turbocharged SAAB 2.3 dm^3 SI-engine. The comparison showed that the method based on the first law of thermodynamics was best suited for diagnosis purposes since it was least sensitive to model errors.

  • 279.
    Andersson, Per
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Observer Based Feedforward Air-Fuel Control of Turbocharged SI-Engines2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    Abstract: Air-fuel control on turbocharged (TC) SI-engines require precise prediction of the cylinder air-charge (CAC). Using an observer it is possible to both estimate the necessary system states and to provide a framework to design the necessary CAC feedforward controller. Here a mean value engine model of a TC SI-engine is used to develop an observer. The output of the observer is fed as an initial condition to a predictor which is used for feedforward of the CAC for air-fuel control. The resulting controller is experimentally validated on a SAAB 2.0 dm^3 TC engine using tip-in and tip-out transients. The results show that the excursions in lambda are less than 5%.

  • 280.
    Andersson, Per
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem. Linköpings universitet, Tekniska högskolan.
    Observer Based Feedforward Air-Fuel Control of Turbocharged SI-Engines2005Ingår i: Proceedings of 16th Triennial World Congress, Prague, Czech Republic, IFAC Papers Online, 2005, Vol. 38, s. 200-205Konferensbidrag (Refereegranskat)
    Abstract [en]

    Air-fuel control on turbocharged (TC) SI-engines require precise prediction of the cylinder air-charge (CAC). Using an observer it is possible to both estimate the necessary system states and to provide a framework to design the necessary CAC feedforward controller. Here a mean value engine model of a TC SI-engine is used to develop an observer. The output of the observer is fed as an initial condition to a predictor which is used for feedforward of the CAC for air-fuel control. The resulting controller is experimentally validated on a SAAB 2.0 dm3 TC engine using tip-in and tip-out transients. The results show that the excursions in Λ are less than 5%

  • 281.
    Andersson, Per
    et al.
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Three Way Catalyst Control using a PI-style Controller with HEGO Sensor Feedback2002Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recent research has shown that control of the oxygen content in the catalyst has potential to further reduce the emissions from spark ignited engines. This gives rise to a cascade structure where an outer loop influences an inner loop. Different ways of augmenting the inner loop, a traditional PI-feedback controller based on feedback from the binary oxygen sensor, are studied. The SI-engine constraints on the control, such as low emissions and drive ability, are considered in the evaluation of the controllers. The result is that a delayed switching of the sensor is needed to control the oxygen content in the TWC using binary sensor feedback.

  • 282. Andersson, Per
    et al.
    Eriksson, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Nielsen, Lars
    Linköpings universitet, Institutionen för systemteknik, Fordonssystem.
    Modelling and Architecture Examples of Model Based Engine Control1999Konferensbidrag (Refereegranskat)
    Abstract [en]

    Environmental regulations and drivability issues are driving forces in the development of control systems for automotive engines. Precise control of the air and fuel is fundamental for achieving the goals. Furthermore, the architecture for the controller plays a central role in how the goals are achieved.

    A comparison is made between two conventional controller structures and a model based structure. The performance of the different control structures is evaluated on a simulation model. To point out the differences the evaluation is concentrated to transient conditions where a step in throttle angle is used as input to the system. In addition, connections between controllers and the engine model is discussed.

  • 283.
    Andersson, Per-Oskar
    Linköpings universitet, Institutionen för systemteknik.
    Rhapsody on small processor platforms2008Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [sv]

    Rhapsody är ett verktyg för modelldriven utveckling och design av inbyggda system och realtidssystem. Syftet med detta examensarbete är att undersöka om Rhapsody kan användas för att utveckla mjukvara till små processorplattformar som Atmel’s AVR. Då Rhapsody normalt används till plattformar med ett operativsystem behöver vissa modifieringar göras för att möjliggöra utveckling mot plattformar utan operativsystem. Dessa modifieringar, deras för och nackdelar samt påverkan på utvecklingsprocessen undersöks medan AVR-mjukvara porteras till Rhapsody. Mjukvaran som porteras är en del av styrsystemet till en av CC Systems produkter: CC Pilot XL II, en robust fordonsdator.

  • 284.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Adaptive Forgetting in Recursive Identification through Multiple Models1984Ingår i: Analysis and Optimization of Systems: Proceedings of the Sixth International Conference on Analysis and Optimization of Systems, Nice, France, 19-22 June, 1984 / [ed] A. Bensoussan, J. L. Lions, New York: Springer Berlin/Heidelberg, 1984, s. 171-185Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    A new recursive identification method, Adaptive Forgetting through Multiple Models — AFMM, is presented and evaluated using computer simulations. AFMM is especially suited for identification of systems with jumping parameters or parameters that change in an irregular fashion. It can be viewed as a particular way of implementing adaptive gains or adaptive forgetting factors for recursive identification. The new method essentialy consists of multiple Recursive Least Squares (RLS) algorithms running in parallel, each with a corresponding weighting factor. The simulations indicate that AFMM is able to track rapidly changing parameters well, and that the method is robust in several respects.

  • 285.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Adaptive Forgetting in Recursive Identification through Multiple Models1984Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A new recursive identification method, adaptive forgetting through multiple models (AFMM) is presented and evaluated using computer simulations. AFMM is especially suited for identification of systems with jumping or rapidly changing parameters. It can be viewed as a particular way of implementing adaptive gains or adaptive forgetting factors for recursive identification. The new method essentially consists of multiple recursive least-squares (RLS) algorithms running in parallel, each with a corresponding weighting factor. The simulations indicate that AFMM is able to track rapidly changing parameters well, and that the method is robust in several respects.

  • 286.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Adaptive Forgetting in Recursive Identification through Multiple Models1983Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A new recursive identification method, adaptive forgetting through multiple models (AFMM) is presented and evaluated using computer simulations. AFMM is especially suited for identification of systems with jumping or rapidly changing parameters. It can be viewed as a particular way of implementing adaptive gains or adaptive forgetting factors for recursive identification. The new method essentially consists of multiple recursive least-squares (RLS) algorithms running in parallel, each with a corresponding weighting factor. The simulations indicate that AFMM is able to track rapidly changing parameters well, and that the method is robust in several respects.

  • 287.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Adaptive Forgetting in Recursive Identification through Multiple Models1983Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A new recursive identification method, adaptive forgetting through multiple models (AFMM) is presented and evaluated using computer simulations. AFMM is especially suited for identification of systems with jumping or rapidly changing parameters. It can be viewed as a particular way of implementing adaptive gains or adaptive forgetting factors for recursive identification. The new method essentially consists of multiple recursive least-squares (RLS) algorithms running in parallel, each with a corresponding weighting factor. The simulations indicate that AFMM is able to track rapidly changing parameters well, and that the method is robust in several respects.

  • 288.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Adaptive Forgetting in Recursive Identification through Multiple Models1985Ingår i: International Journal of Control, ISSN 0020-7179, E-ISSN 1366-5820, Vol. 42, nr 5, s. 1175-1193Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new recursive identification method, adaptive forgetting through multiple models (AFMM) is presented and evaluated using computer simulations. AFMM is especially suited for identification of systems with jumping or rapidly changing parameters. It can be viewed as a particular way of implementing adaptive gains or adaptive forgetting factors for recursive identification. The new method essentially consists of multiple recursive least-squares (RLS) algorithms running in parallel, each with a corresponding weighting factor. The simulations indicate that AFMM is able to track rapidly changing parameters well, and that the method is robust in several respects.

  • 289.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Adaptive Forgetting through Multiple Models and Adaptive Control of Car Dynamics1983Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    A new recursive identif ication method, Adaptive Forgetting through Multiple Models - AFMM, is presented and evaluated using computer simulations. AFMM is specif ically suited for identification of systems with jumping or rapidly changing parameters. It can be viewed as a particular way of implementing adaptive gains or adaptive forgetting factors for recursive identif ication. The new method essentiallyconsists of multiple Recursive Least Squares (RLS) algorithms running in parallel, each with a corresponding weighting factor. The simulations indicate that AFMM is able to track rapidly changing parameters well, and that the method is robust in several respects.

  • 290.
    Andersson, Peter
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Charge Transport Modulation and Optical Absorption Switching in Organic Electronic Devices2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Organic electronics has evolved into a well-established research field thanks to major progresses in material sciences during recent decades. More attention was paid to this research field when “the discovery and development of conductive polymers” was awarded the Nobel Prize in Chemistry in 2000. Electronic devices that rely on tailor-made material functionalities, the ability of solution processing and low-cost manufacturing on flexible substrates by traditional printing techniques are among the key features in organic electronics. The common theme while exploring organic electronics, and the focus of this thesis, is that (semi-)conducting polymers serve as active materials to define the principle of operation in devices.

    This thesis reviews two kinds of organic electronic devices. The first part describes electrochemical devices based on conducting polymers. Active matrix addressed displays that are printed on flexible substrates have been obtained by arranging electrochemical smart pixels, based on the combination of electrochemical transistors and electrochromic display cells, into cross-point matrices. The resulting polymer-based active-matrix displays are operated at low voltages and the same active material is used in the electrochemical transistors as well as in the electrochromic display cells, simply by employing the opto-electronic properties of the material. In addition to this first part, a switchable optical polarizer based on electrochromism in a stretch-aligned conducting polymer is described. The second part reports switchable charge traps in polymer diodes. Here, a device based on a solid-state blend of a conjugated polymer and a photochromic molecule has been demonstrated. The solid state blend, sandwiched between two electrodes, provide a polymer diode that allows reversible current modulation between two different charge transport mechanisms via externally triggered switching of the charge trap density.

    Delarbeten
    1. Active Matrix Displays Based on All-Organic Electrochemical Smart Pixels Printed on Paper
    Öppna denna publikation i ny flik eller fönster >>Active Matrix Displays Based on All-Organic Electrochemical Smart Pixels Printed on Paper
    Visa övriga...
    2002 (Engelska)Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 14, nr 20, s. 1460-1464Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    An organic electronic paper display technology (see Figure and also inside front cover) is presented. The electrochromic display cell together with the addressing electrochemical transistor form simple smart pixels that are included in matrix displays, which are achieved on coated cellulose-based paper using printing techniques. The ion-electronic technology presented offers an opportunity to extend existing use of ordinary paper.

     

    Ort, förlag, år, upplaga, sidor
    Weinheim, Germany: Wiley-VCH Verlagsgesellschaft, 2002
    Nyckelord
    Displays, active matrix, Electronic paper, Poly(3, 4-ethylenedioxythiophene) (PEDOT), Polystyrene sulfonate (PSS)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-12763 (URN)10.1002/1521-4095(20021016)14:20<1460::AID-ADMA1460>3.0.CO;2-S (DOI)000179034200004 ()
    Tillgänglig från: 2008-11-12 Skapad: 2008-11-12 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    2. Organic Electrochemical Smart Pixels
    Öppna denna publikation i ny flik eller fönster >>Organic Electrochemical Smart Pixels
    Visa övriga...
    2003 (Engelska)Ingår i: Materials Research Society Symposium Proceedings, 2003, Vol. 736, s. D6.6-Konferensbidrag, Publicerat paper (Refereegranskat)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-12764 (URN)
    Tillgänglig från: 2008-11-12 Skapad: 2008-11-12 Senast uppdaterad: 2017-02-03
    3. Switchable Optical Polarizer Based on Electrochromism in Stretch-Aligned Polyaniline
    Öppna denna publikation i ny flik eller fönster >>Switchable Optical Polarizer Based on Electrochromism in Stretch-Aligned Polyaniline
    2003 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 83, nr 7, s. 1307-1309Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We report on the polarizing electrochromic (EC) effect of a conjugated polymer. This has been achieved in a planar flexible electrochemical device cell comprised of a patterned stretch-aligned thin film of polyaniline and an electrolyte, all made on a polyethylene foil substrate. The resulting device exhibits polarized absorption characteristics, of a dichroic ratio of 4, that can be controlled by the voltage applied. Also, thin flexible EC polarizers have been realized by combining two stretch-aligned polyaniline films with orthogonal stretching direction. In the resulting EC polarizer the orientation of the polarized absorption can be switched between two orthogonal directions, depending on the voltage applied.

    Nyckelord
    optical polymers, electrochromism, polymer films, optical polarisers
    Identifikatorer
    urn:nbn:se:liu:diva-13799 (URN)10.1063/1.1602556 (DOI)
    Tillgänglig från: 2008-11-12 Skapad: 2008-11-12 Senast uppdaterad: 2017-12-13
    4. Printable All-Organic Electrochromic Active-Matrix Displays
    Öppna denna publikation i ny flik eller fönster >>Printable All-Organic Electrochromic Active-Matrix Displays
    2007 (Engelska)Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 17, nr 16, s. 3074-3082Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    All-organic active matrix addressed displays based on electrochemical smart pixels made on flexible substrates are reported. Each individual smart pixel device combines an electrochemical transistor with an electrochromic display cell, thus resulting in a low-voltage operating and robust display technology. Poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) served as the active material in the electrochemical smart pixels, as well as the conducting lines, of the monolithically integrated active-matrix display. Different active-matrix display addressing schemes have been investigated and a matrix display fill factor of 65 % was reached. This is achieved by combining a three-terminal electrochemical transistor with an electrochromic display cell architecture, in which an additional layer of PEDOT:PSS was placed on top of the display cell counter electrode. In addition, we have evaluated different kinds of electrochromic polymer materials aiming at reaching a high color switch contrast. This work has been carried out in the light of achieving a robust display technology that is easily manufactured using a standard label printing press, which forced us to use the fewest different materials as well as avoiding exotic and complex device architectures. Together, this yields a manufacturing process of only five discrete patterning steps, which in turn promise for that the active matrix addressed displays can be manufactured on paper or plastic substrates in a roll-to-roll production procedure.

    Nyckelord
    Displays, Electrochromic materials, Electronic paper
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-12766 (URN)10.1002/adfm.200601241 (DOI)
    Tillgänglig från: 2008-11-12 Skapad: 2008-11-12 Senast uppdaterad: 2017-12-14
    5. Switchable Charge Traps in Polymer Diodes
    Öppna denna publikation i ny flik eller fönster >>Switchable Charge Traps in Polymer Diodes
    2005 (Engelska)Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 17, nr 14, s. 1798-1803Artikel i tidskrift (Refereegranskat) Published
    Nyckelord
    Charge trapping, Optical switches, Photoisomerization, Poly(3, 4-ethylenedioxythiophene (PEDOT)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-12767 (URN)10.1002/adma.200400842 (DOI)
    Tillgänglig från: 2008-11-12 Skapad: 2008-11-12 Senast uppdaterad: 2017-12-14
    6. Diodes Based on Blends of Molecular Switches and Conjugated Polymers
    Öppna denna publikation i ny flik eller fönster >>Diodes Based on Blends of Molecular Switches and Conjugated Polymers
    2005 (Engelska)Ingår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, ISSN 0379-6779, Vol. 150, nr 3, s. 217-221Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Here we report polymer diodes based on a conjugated polymer host and a dispersed molecular switch. In this case, the molecular switch is a photochromic (PC) molecule that can be reversibly switched between low and high energy gap states, triggered by exposure to ultra-violet and visible light, respectively. While dispersed inside the conjugated polymer bulk and switched to its low energy gap state, the PC molecules act as traps for holes. Solid-state blends of this PC material and conjugated polymers have been demonstrated in diodes. The state of the PC molecule controls the current density versus voltage (JV) characteristics of the resulting diode. Both poly(2-methoxy-5(2′-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) and poly(3-hexylthiophene-2,5-diyl) (P3HT) host materials have been studied. The two conjugated polymers resulted in differing JV switching characteristics. A more pronounced JV switch is observed with MEH-PPV than with P3HT. We postulate that the PC material, while switched to its low energy gap state, act as traps in both the conjugated polymers but at different trap depth energies.

    Nyckelord
    Polymer diodes, Molecular switch, Photochromic molecule, Charge trap depth, JV modulation
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-12768 (URN)10.1016/j.synthmet.2004.06.035 (DOI)
    Tillgänglig från: 2008-11-12 Skapad: 2008-11-12 Senast uppdaterad: 2017-12-14
  • 291.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Control of a Diesel Generator with Varying Dynamics: A Comparison of Different Adaptive and Constant Regulators1984Rapport (Övrigt vetenskapligt)
  • 292.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik.
    Design of a channel board used in an electronic warfare target simulator2006Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    A channel board was designed for a DRFM circuit. The DRFM is implemented in a Virtex-4 FPGA from Xilinx. In the future a similar channel board is intended to be used for target echo generation in ELSI which is an electronic warfare simulator at Saab Bofors Dynamics in Linköping.

    Besides the DRFM circuit the channel board consists of analog-to-digital converters, digital-to-analog converters, Ethernet plug-in board with a microcontroller, voltage regulators, FPGA configuration memory, voltage amplifiers, current amplifiers, oscillator, buffers/drivers and bus transceivers. The sample rate is 200 MHz and LVDS signalling standard is used between the DRFM circuit and the converters.

    The channel board has a JTAG interface which enables in-system programming of the FPGA. This implies that the DRFM can easily be redesigned. An external computer can manage the channel board via Ethernet. Software was developed for the microcontroller on the channel board and for the external computer. The function of the channel board is heavily dependent on the DRFM circuit.

    The channel board design resulted in the assembly of a prototype circuit board. Measurements were performed in a lab and the channel board was approved to be integrated in ELSI for further tests.

  • 293.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik.
    Implementering av digitalt vågfilter av Richardstyp i FPGA2002Självständigt arbete på grundnivå (yrkesexamen)Studentuppsats
    Abstract [sv]

    Ett digitalt vågfilter av Richardstyp har implementerats i en FPGA på ett utvecklingskort. Sampel kan skickas till filtret och mottas från filtret via serieporten på en dator. Metoden som användes är att en modell av filtret konstruerades i Simulink. Filtret har modifierats med avseende på skalning, brus och stabilitet. VHDL-koden till filtret genererades i Simulink genom att bygga modellen av Xilinx Blockset. Ytterligare VHDL-kod konstruerades för att kunna skicka sampel mellan filter och minnet på utvecklingskortet. För kommunikation mellan minnet på utvecklingskortet och dator utnyttjades färdiga lösningar.

  • 294.
    Andersson, Peter
    Linköpings universitet, Institutionen för systemteknik.
    Överföring av digital video via FireWire2002Självständigt arbete på grundnivå (yrkesexamen)Studentuppsats
    Abstract [en]

    Transmission of digital signals is today more frequently used than transmission of analog signals. One reason for this is that a digital signal is less sensitive to noise than an analog, another reason is that almost all signals today are handled in a digital format. This thesis describes the development of a system that receives digital video signals through FireWire. The standard for FireWire, which is a high performance serial bus, is under development. Today the standard of the bus supports transmission of data with a speed of up to 400 Mbit/s. In the future FireWire is supposed to transmit data with a speed of up to 3,2 Gbit/s. The thesis gives an introduction to the technique for FireWire and how it is implemented. It also includes a short description of digital video signals in DVCAM format.

  • 295.
    Andersson, Peter
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Ljung, Lennart
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    A Test Case for Adaptive Control: Car Steering1981Ingår i: Proceedings of the 1981 IFAC Symposium on Theory and Applications of Digital Control, 1981Konferensbidrag (Refereegranskat)
  • 296.
    Andersson, Peter
    et al.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Ljung, Lennart
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    A Test Case for Adaptive Control: Car Steering1981Rapport (Övrigt vetenskapligt)
  • 297.
    Andersson, Pontus
    Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Visuell processreglering2007Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats
    Abstract [sv]

    Examensarbetet handlar om att ta fram en processmodell för nivåreglering och det innehåller flera utmaningar. Vätskesystemets dynamik och balans måste beaktas likväl som lämpliga reglermetoder samt modellens utseende. I den här rapporten behandlas hela händelseförloppet från initialskedet till en färdig produkt redo att visas för en publik. Läsaren får möjlighet att närmare granska de komponenter som modellen är uppbyggd av, ta del av programmeringsarbetet och de omfattande test av modellen som utförts. Flera teknikområden belyses men fokus riktas särskilt på ABB:s styrsystem AC800M/800xA, fältbussteknik och reglerstrategier. PID-regulatorn har under arbetet spelat en stor roll och reglerstrategier som innefattar bl.a. framkoppling och kaskadkoppling analyseras och diskuteras. För att bedöma skillnader i val av reglermetod används grafer från praktiska försök. Rapportens upplägg med flertalet illustrationer och den genomgripande tekniska dokumentationen hjälper läsaren att förstå modellens funktion och uppbyggnad.

  • 298.
    Andersson, Rickard
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem.
    Algorithm for Handoff in VDL mode 42010Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    VDL mode 4 is a digital data link operating in the VHF band, its mainly use is for the aviation industry.VDL4 can as an example provide with positioning data, speed information of aircrafts or vehicles equipped with a VDL4 transponder. A connection between the groundsystem and the airborne system is called a point to point connection, which can be used for various applications. This data link needs to be transferred between groundstations during flights in order maintain the connection, which is called handoff.

    The handoff process needs to be quick enough to not drop the link and at the same time a low rate of handoffs is desirable. The data link is regarded as a narrow resource and link management data for handoff is considered as overhead.

    This thesis studies how to make the handoff procedure optimal with respect to involved aspects. Previous research of handoff algorithms and models of the VHF-channel are treated. Standardized parameters and procedures in VDL4 and are explored in order to find an optimal solution for the handoff procedure in VDL4.

    The studied topics are analyzed and it is concluded to suggest an algorithm based on an adaptive hysteresis including signal quality and positioning data provided in VDL4. Standardized parameters which could be useful in the handoff procedure are commented, since the VDL4 standards are under development.

  • 299.
    Andersson, Rikard
    et al.
    Linköpings universitet, Institutionen för datavetenskap.
    Emberg, Johan
    Linköpings universitet, Institutionen för datavetenskap.
    Hazell, Sofie
    Linköpings universitet, Institutionen för datavetenskap.
    Laestander, Hjalmar
    Linköpings universitet, Institutionen för datavetenskap.
    Norberg, Gustaf
    Linköpings universitet, Institutionen för datavetenskap.
    Elmfeldt Rönnmark, Maximilian
    Linköpings universitet, Institutionen för datavetenskap.
    Buciuto Sundelin, Bruno
    Linköpings universitet, Institutionen för datavetenskap.
    Törngren, Erik
    Linköpings universitet, Institutionen för datavetenskap.
    Heat n' Eat: Utvecklingen av en användbar e-butik med fokus på navigerbarhet2017Självständigt arbete på grundnivå (kandidatexamen), 12 poäng / 18 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Studenter idag har brist på både tid och pengar. Samtidigt ökar e-handeln och specifikt matförsäljningen över internet. Rapporten har som avsikt att undersöka möjligheterna för en tjänst, i form av en webbapplikation, som erbjuder studenter högkvalitativ mat inom deras budget på ett enkelt sätt. Via en marknadsundersökning på Campus Valla uttryckte studenter avsaknad av en sådan tjänst. Studien genomfördes genom att ta fram teori rörande användbarhet och navigerbarhet. Studenter som grupp har ofta ont om tid och är vana vid att få snabb och tydlig information vilket god navigerbarhet säkerställer. Efter teoristudien genomfördes användartester på målgruppen. Som ett resultat utvecklades webbapplikationen Heat n’ Eat. För att uppnå god navigerbarhet blev utformningen en simpel struktur med produkterna i fokus. Ett avslutande användartest visade att webbapplikationen kan anses vara användbar med fokus på navigerbarhet.

  • 300.
    Andersson, Robby
    Linköpings universitet, Institutionen för systemteknik.
    FPGA design of a controller for a CAN controller.2003Självständigt arbete på grundnivå (yrkesexamen)Studentuppsats
    Abstract [en]

    This diploma work describes how an FPGA is designed to control a CAN controller. It describes the different tools used when working with Actel’s design tools and the sequence of work applied. It gives a short overview of a multiplexer, the CAN bus, an analog/digital-converter and some more information on the actual FPGA. It also brings up the design process of the FPGA, planning, coding, simulating, testing and finally programming the FPGA. The different parts implemented in the FPGA are a shift-register and two state- machines that are connected with each other. They work together to control the SJA1000 CAN controller made by Philips. They also receive data from the analog/digital-converter that they forward onwards to the CAN controller that forward the data on the CAN bus.

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