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  • 101.
    Landin, Per Niklas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A review of validation criteria for behavioral power amplifier models2008Conference paper (Other academic)
  • 102.
    Landin, Per Niklas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Comparison of Evaluation Criteria for Power Amplifier Behavioral Modeling2008In: IEEE MTT-S International Microwave Symposium Digest; 2008, Atlanta, GA, USA, 2008, p. 1441-1444Conference paper (Refereed)
  • 103.
    Landin, Per Niklas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Keskitalo, Niclas
    University of Gävle, Center for RF Measurement Technologies.
    Tornblad, Olof
    A Study of memory effects of RF power LDMOS before and after digital predistortion2009In: Wireless and Microwave Technology Conference, 2009. WAMICON '09. IEEE 10th Annual, 2009, p. 1-5Conference paper (Refereed)
    Abstract [en]

    Sideband asymmetries in distortion products are created due to electrical and thermal memory effects and this can be difficult to correct for in a digital predistortion algorithm. In this study, sideband asymmetries in third-order intermodulation distortion products before and after digital predistortion were investigated using 2-tone and 2-carrier WCDMA signals. The parallel Hammerstein (PH) model was used in the digital predistortion algorithm. The sign of the asymmetries before correction were found to depend on power level. Memoryless correction lead to an increase in asymmetries for some power ranges whereas using a PH model of order 13 with only one order of memory length lead to good correction over a large power range.

  • 104. Litwin, Andrej
    et al.
    Bengtsson, Olof
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Olsson, Jörgen
    Novell BiCMOS Compatible, Short Channel LDMOS Technology for Medium Voltage RF & Power Applications2002In: IEEE MTT-S Digest, 2002, p. 35-38Conference paper (Refereed)
    Abstract [en]

    We describe a very short channel, 0.15 μm, LDMOS transistor, with a breakdown voltage of up to 45 V, manufactured in a standard 0.35 μm BiCMOS process. At 1900 MHz and a 12V supply voltage the 0.4mm gate width device gives 100 mW output power P1 dB at a drain efficiency of 43%. It has a transducer power gain of more than 20dB and a current gain cutoff frequency, fT, of 13 GHz. The maximum available gain cutoff frequency, fMAX, is 27 GHz. The LDMOS process module does not affect the performance or models of other devices. We present for the first time a simple way to create high voltage, high performance LDMOS transistors for RF power amplifier use even in a very downscaled silicon technology.

  • 105.
    Luque, Carolina
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Improved dynamic range for multi-tone signal using model-based pre-distortion2009In: Metrology and measurement systems, ISSN 0860-8229, Vol. 16, no 1, p. 129-141Article in journal (Refereed)
  • 106.
    Luque, Carolina
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Improved dynamic range for multi-tone signal using model-based pre-distortion2008In: Proceedings of the 13th Workshop on ADC Modelling and Testing, 2008, p. 1003-1007Conference paper (Refereed)
    Abstract [en]

    Some test and measurement applications require higher dynamic range for multi-tone signals than a signal generator can generate. Moreover, for other applications it can be interesting to improve the performance of a “low cost” signal generator. The spectral purity of generated signals can be improved by using pre-distorted base-band signals. In this paper, a dynamic grey-box model is described. A pre-distorter is used in order to improve the dynamic range. The results, which are based on measurements, show an improved dynamic range for a three-tone signal of approximately 9 dB and an improved ACPR of 5 dB for a WCDMA signal.

  • 107.
    Luque, Carolina
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Model-Based Pre-Distortion for Signal Generators2008In: GigaHertz Symposium 2008: abstract book, Göteborg: Chalmers , 2008, p. 88-88Conference paper (Refereed)
  • 108. Medawar, Samer
    et al.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Jansson, Magnus
    Dynamic characterization of analog-digital-converters2007In: Mosharaka International Conference on Wireless Communications and Mobile Computing, 2007Conference paper (Refereed)
  • 109. Medawar, Samer
    et al.
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Jansson, Magnus
    ADC characterization by dynamic integral nonlinearity2008In: Proceedings of the 13th Workshop on ADC Modelling and Testing, 2008, p. 1037-1042Conference paper (Refereed)
    Abstract [en]

    Wide band characterization of analog-digital converter integral nonlinearity (INL) based on parametric modeling and least-squares parameter t is performed. In particular, the variations in the INL due to the frequency of the ADC stimuli are modeled. The INL is divided into two main entities describing the static and dynamic behavior of the ADC, respectively. The static component is modeled by a high code component (HCF) of piecewise linear segments centered around zero. A static low code (LCF) polynomial inherent to the INL data is added to the segments to complete the static part of the model. The INL dynamic part is modeled by an LCF polynomial. Method implementation is considered and is applied to 12-bit ADC data at 210 MSPS.

  • 110.
    Mengistu, Jomo
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Study of The Electrical Properties of Pacemaker Leads2008Independent thesis Basic level (degree of Bachelor), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

     

    Abstract

    The purpose of this thesis is to examine the electrical properties of pacemaker leads by measurements and theoretical analysis.

    If time allows, recommendations on how to construct a simple circuit model to explain the phenomenon will be given based on the electrical properties obtained from measurements performed during the work of this thesis. Additional information on pacemaker lead heating during impact of magnet in X-ray (MRI) will be presented if time allows. Significant electrical properties of pacemaker leads are compiled in this thesis.

     

    ANALYSIS OF CIRCUIT MODEL

    The purpose of this model is to create an equivalent electronic circuit model that describes a pacemaker lead electrical property. The model is divided into three different sections: proximal part, the homogeneous coil part and the distal end.  The model will include series inductance, parallel capacitance, series resistance, lossless admittance and winding capacitance between each loop for the homogeneous coil part, additionally the impedance of the proximal and distal part will be included.

  • 111.
    Miranda, Juan
    et al.
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Gidlund, Mikael
    Coded OFDM in hybrid radio over fibre links2008In: GigaHertz Symposium 2008: Abstract Book, Göteborg: Chalmers , 2008, p. 16-16Conference paper (Other academic)
    Abstract [en]

    Distributed antenna systems based on Radio over Fiber (RoF) has proofed to be the most efficient solution to achieve in-building coverage in 3G systems [1]. Today 3G uses an air interface based on WCDMA. However, Coded Orthogonal Frequency Division

    Multiplexing (COFDM), has been selected in IEEE802.11a, WiMax and the long term evolution of 3G (LTE) due to its flexibility and robustness in fading environments [2].

    The objectives of the present investigation are therefore to examine the OFDM reliability in the nonlinearities and multipath posed by the RoF link, and how its performance can be improved by using representative linear block codes.

    As a measure of reliability, the Bit Error Rate (BER) of the uncoded and coded OFDMRoF system for Uplink (UL) and Downlink (DL) was simulated. The system modeling

    considers multipath fading from radio transmission [3] and Amplitude-to-Amplitude (AM/AM) and Amplitude-to-Phase (AM/PM) distortions produced by the Electrical-to-

    Optical (E/O) conversion and amplifying stages of the fiber link [4]. Several BCH and Reed-Solomon codes were studied with different code rates [5], complexity and interleaving depth. Their properties are related to system parameters such as Bit Energy

    per Noise Density, Input Back-Off (IBO) and modulation order.

    The Results show that using 4-QAM modulation with a moderate Input Back-Off (i.e. 4- 10dB), BCH and small Reed-Solomon codes can reduce BER by a factor even greater

    than 10 depending on the IBO. However, using 16-QAM modulation BER reduction is poor even if Reed-Solomon is used with large number of bits per symbol.

    Future work would consider using a more complex model for the E/O conversion and power amplifier, more sophisticated codes such as Turbo or LDPC, and the use of nonlinear channel

    estimation to further enhance system performance.

  • 112.
    Moradi Shahrbabak, Shahla
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Usereffect on mobile terminal antenna2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The study is concerned with how the hane effects on matching on mobile terminal antennas.

  • 113.
    Nader, Charles
    et al.
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Landin, Per Niklas
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Björsell, Niclas
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wisell, David
    Ericsson AB.
    Händel, Peter
    KTH, EES, Signal processing lab.
    Andersen, Olav
    Ericsson AB.
    Keskitalo, Niclas
    University of Gävle, Center for RF Measurement Technologies.
    Wideband Power Amplifiers Characterization by Undersampling: Zhu-Frank Sampling Theorem2009Conference paper (Other academic)
  • 114.
    Nordin Hellström, Kristopher
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Williams, Kenny
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Radiolänk med GNU Radio2008Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    At the Department of Technology and Built environment at the University of Gävle there was an interest to study GNU Radio, which is an "open source radio project. The project is based on that most of the radio signal processing is made in an ordinary PC. The idea behind this degree project was that in a laptop there are several radio transmitters/receivers that takes space, generates heat and transmit in varied frequency band etcetera.

     

    All these radio transmitters/receivers could be replaced with a Software Defined Radio system. It means that one common, general radio hardware is used to different communications such as: WLAN, Bluetooth, GPRS, 3G etcetera. The waveform is generated in the software, which makes the system very flexible. To transmit and receive radio signals a USB-based hardware is required, for example from Ettus Research LLC.

     

    During this degree project two PC:s was used for the signal processing and the signal transferring. The operating system that was used on the computers, were the Linux based Ubuntu 8.04. To generate the signals, to modulate/demodulate the signals and to get the communication on the sound cards in/out-port working, the different packages in the GNU Radio software was used and for programming the high level language, Python, was used.

     

    In this degree project a lot of experiments where made, for example a sine wave was generated in computer 1 and the signal was amplitude modulated and transferred to computer 2, through the sound card. In computer 2 the signal was demodulated and filtrated, before it was saved to the hard drive. When the signal was saved on computer 2, it could be sent out on the sound card and be studied on an oscilloscope. This transfer between the computers was made with a stereo cable, but also with a radio link equipment on the University of Gävle.

     

    The result of this degree project was satisfying, because the signal was possible to modulate, transfer, demodulate and save. In the wire transfer a lot of noise was generated on to the signal, mostly because of the sound cards. When the wireless transfer was made it appeared more noise, because of the quality of the receiver, the transmitter and the antennas.

     

    This work can be developed to more advanced systems.

  • 115.
    Nordlander, Edvard
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Cortas Nordlander, Maria
    Vasaskolan, Gävle.
    Konsten att berätta en god historiaManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [sv]

    Problemlösning uppfattas av många elever som en svårighet att övervinna genom att försöka lära sig utantill. Detta synsätt betecknar en algoritmisk inställning till lärande och har egentligen mycket lite med problemlösning att göra. Man sätter sin tillit till att upprepning av recept ger lika gott resultat oavsett problemställning. Vissa tycker dessutom att ett felaktigt resonemang, eller ett resonemang med bristfälliga eller obefintliga motiveringar, kan anses vara acceptabelt så länge svaret är korrekt.

    För att förebygga en algoritmisk inställning till problemlösning kan man införa en strategi för att förbättra problemlösningsförmågan hos elever – en metod som alla elever kan ta till sig. Att systematiskt teckna uppgiften är detsamma som att metodiskt reda ut för sig själv vad uppgiften går ut på, vilka teoretiska resonemang man kan tillämpa, hur man kan tänkas lösa uppgiften grundat på dessa teoretiska resonemang, samt slutligen genomföra lösningen på ett tydligt sätt. En god idé är att tänka sig att någon annan skall kunna följa resonemanget utan några andra hjälpmedel än den beskrivning som eleven själv producerar.

    De flesta brukar fascineras av en god historia. Det gäller för pedagogen att fånga intresset genom att framställa sin kunskap i berättandets form på ett begripligt, metodiskt uppbyggt och trovärdigt sätt. Även matematisk eller tillämpad problemlösning kan beskrivas för elever på detta vis p.g.a. sin logiska uppbyggnad.

    Man kan indela en god historia i fyra oundgängliga punkter: ingress, intrig, uppbyggnad av spänning och, slutligen, upplösning. Härutöver kan man tillägga ytterligare två punkter för att förgylla berättandet, nämligen prolog och epilog.

  • 116.
    Nordlander, Edvard
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Grenholm, Jan
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Hur påverkar kön och etnisk bakgrund intresset för tekniska studier?2007In: Genusvetenskapligt symposium "Forskning och förändring: genusvetenskapen och dess konsekvenser": Gävle, Sverige, November 2007, 2007Conference paper (Other academic)
    Abstract [sv]

    Skolämnet Teknik har funnits i den svenska grundskolan ett drygt tjugotal år i någon form och ett drygt tiotal år som eget ämne. Likväl visar ett flertal undersökningar att teknikämnet inte alls fått den plats och aktning som det rimligen förtjänar, dels ur ett samhällsperspektiv och dels ur läroplansperspektiv. Studier av i första hand kvinnors attityder till ordet teknik visar att sexåringar inte har en aning om vad ordet betyder. Vissa har dock ett minne av att ha hört ordet och anser att det måste vara något svårt, eftersom ”pappa jobbar med teknik”. Dessa föreställningar är också mycket vanliga hos pojkar i samma ålder. Bland tioåringarna är kunskaperna något mer avancerade. Man kan där koppla ordet till vanliga tekniska företeelser i omgivningen, såsom sladdar, TV m.m. Men det förekommer också att ordet företrädesvis kopplas till betydelser i idrottssammanhang, som t.ex. åktekniken i slalom. Hos vuxna kvinnor associeras ordet till mekaniska anordningar. De fantasifulla kugghjulen från vinjetten i det sedan länge avsomnade TV-programmet Tekniskt Magasin föresvävar fortfarande åtskilliga som prototypen för teknik.

     

    Hur kan det vara så? Är teknik ett ord som har magiska förtecken eller kanske t.o.m. skrämmer? Tekniken omger oss alla och utnyttjas flitigt av alla! Vilken tonåring idag tvekar att använda en mobiltelefon till de mest avancerade uppgifter? Vilka barn är rädda att använda datorer i sin vardag, t.ex. till chattande? Vilka avstår från att använda mp3-spelare? Troligen inga alls!

     

    Men om nu tekniken är en naturlig del av vardagen så borde det ju finnas ett större intresse av att förstå vad som döljer sig bakom. Likväl är intresset för teknik som skolämne och karriärväg mycket lågt idag. Om denna trend fortsätter kommer landet att utarmas på kvalificerad teknisk arbetskraft och därmed försätta landets teknikintensiva industri i ett långsiktigt dilemma. Utan tillgång till kvalificerad teknisk arbetskraft finns det ingen utvecklingspotential i företagen och därmed inte heller någon framtid. Landets välstånd hotas således!

     

    Ett skäl kan vara att teknikundervisningen i grundskolan inte inspirerar eleverna som den borde. Högskolan i Gävle lanserar hösten 2007 en stor enkätundersökning bland aktiva tekniklärare i grundskolan för att klarlägga vilka faktorer som påverkar undervisningen och dess resultat. En väsentlig del i denna enkät berör kön och etnicitet. Enkätfrågorna behandlar t.ex. om läraren märker några skillnader i intresse för teknikämnet resp. tekniska sammanhang i allmänhet mellan flickor och pojkar. Frågan uppspaltas även för att få könsuppdelat perspektiv på attityderna hos elever med invandrarbakgrund. Frågan ställs i relation till betygsintresse, gruppåverkan (kamraters attityder och förväntningar), föräldrapåverkan m.m. och huruvida teknikämnet i grundskolan påverkar attityderna till teknik i positiv riktning för tekniska och naturvetenskapliga studier i gymnasieskolan.

     

    Stiftelsen den Göranssonska Fonden, Region Gävleborg (Gävleborgs kommuner och landsting) samt DoRiS har bidragit ekonomiskt till projektet.

  • 117.
    Nordlander, Edvard
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Grenholm, Jan
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Teknikämnet i grundskolan: en lokal förstudie av teknikämnets roll i utbildning och samhälle2007In: Første nordiske konferanse i Fagdidaktikk mellom skole og lærerutdanning (NOFA 1): Oslo, Norge, Maj 2007, 2007Conference paper (Other academic)
    Abstract [sv]

    Skolämnet Teknik har funnits i den svenska grundskolan ett tjugotal år i någon form och ett tiotal år som eget ämne. Likväl visar ett flertal undersökningar att teknikämnet inte alls fått den plats och aktning som det rimligen förtjänar, dels ur ett samhällsperspektiv och dels ur läroplansperspektiv. Detta är på sikt skadligt för landets välfärd och orsakerna förtjänar att uppmärksammas.

    Intresset för teknik som skolämne och karriärväg är mycket lågt idag. Om denna trend fortsätter kommer landet att utarmas på kvalificerad teknisk arbetskraft och därmed försätta landets teknikintensiva industri i ett långsiktigt dilemma. Utan tillgång till kvalificerad teknisk arbetskraft finns det ingen utvecklingspotential i företagen och därmed inte heller någon framtid. Tanken på utflyttning ligger således nära till hands.

    Vi kan inte stillatigande konstatera att förutsättningarna till välstånd i landet försvinner. Vi måste i alla fall förstå orsakerna! Vid Högskolan i Gävle har en mångvetenskaplig didaktisk förstudie av hinder och möjligheter för lärare och skolledare att ge teknikämnet en betydande roll i grundskolan påbörjats. I första hand kommer Gävleregionens grundskolor att vara studieobjekt. Om det visar sig att Gävleregionens grundskolor är signifikativa för landet i övrigt genom jämförelser med tidigare utförda nationella undersökningar, så kan dessa skolor utnyttjas för djupdykning/forskning i identifierade problemområden utifrån ett didaktiskt perspektiv.

    Förstudiens upplägg är av kvantitativ/statistisk karaktär i form av en stor enkätundersökning. Ungefär 100 frågor ingår i enkäten och målet är att c:a 1000 aktiva tekniklärare i regionens grundskolor skall deltaga i undersökningen. Härmed förutsätts att nationell signifikans uppnås i resultaten. Upplägget beaktar såväl genusaspekter som etniska aspekter på problematiken. Förstudien finansieras huvudsakligen av en privat fond med viss anknytning till Sandvik AB.

    Resultatet av förundersökningen och fortsatt teknikdidaktisk forskning skall påverka lärarutbildningen nationellt.

    En presentation av bakgrund/syfte, upplägg, resultat och slutsatser ges vid konferensen.

  • 118.
    Nordlander, Edvard
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Grenholm, Jan
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Cortas Nordlander, Maria
    Vasaskolan, Gävle.
    Enkätundersökning av teknikämnets ställning i grundskolan2008In: 9:e rikskonferensen ”Tekniken i skolan”: Norrköping, Sverige, April 2008, 2008Conference paper (Other academic)
    Abstract [sv]

    En stor enkätundersökning av tekniklärarnas syn på ämnets roll i grundskolan har genomförts. Här presenteras ämnets status, lärarnas egen insats, deras utbildnings relevans samt behov av fort- och vidareutbildning, ämnets förmåga att intressera elever för teknik med särskilt fokus på kön och etnicitet, samt dess dragkraft till vidare studier i teknik.

  • 119.
    Nordlander, Edvard
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Grenholm, Jan
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Cortas Nordlander, Maria
    Vasaskolan, Gävle.
    Tekniklärares uppfattning om teknikämnet i den svenska grundskolan2009Conference paper (Other academic)
    Abstract [sv]

    Skolämnet Teknik har funnits i den svenska grundskolan ett knappt trettiotal år i någon form och i 15 år som eget ämne. Likväl visar ett flertal undersökningar att teknikämnet ofta missköts. Kopplingen mellan teknik som skolämne och teknisk karriärväg är tydlig, men trots detta är intresset för högre studier i teknik mycket lågt i Sverige. Om denna trend fortsätter kommer landet att utarmas på kvalificerad teknisk arbetskraft och därmed försätta landets teknikintensiva industri i en långsiktig utvecklingskris.

     

    En stor, webbaserad, ämnesdidaktisk enkätundersökning av kvantitativ/statistisk karaktär om teknikämnet status i grundskolan, har genomförts under 2007 och början av 2008. Undersökningen beaktar såväl genusaspekter som etniska aspekter på problematiken. Av 561 tillfrågade lärare har 325 (c:a 59%) från 32 svenska kommuner påbörjat enkäten. Av naturliga skäl representerar huvuddelen (c:a 65%) av deltagarna Gävle och Sandvikens kommuner. 302 deltagare (c:a 54%) har fullföljt hela enkäten. Resultaten jämförs med tidigare utförda nationella undersökningar för generaliseringar.

     

    Av de deltagande lärarna var c:a 68% kvinnor och c:a 32% män. Merparten är födda i perioden 1947-76 med en ganska jämn fördelning i 5-årsintervall däremellan. Majoriteten anser sig vara eldsjäl för teknikämnet i någon mening, vilket kan snedvrida resultatet i positiv riktning.

     

    Tekniklärarnas åsikt om bl.a. följande frågor kommer att behandlas under konferensen:

     

    • Är de väl utbildade för uppdraget som tekniklärare jämfört med läraruppdraget i stort?
    • Tycker de att teknikkunskaper är viktiga för eleverna och deras framtid?
    • Vad anser de att teknikämnet har för funktion att fylla för eleverna och deras framtid?
    • Hur säkra upplever de sig i att undervisa teknik?
    • Vilka ämnen prioriteras inom lärarkollegiet resp. skolledningen framför teknikämnet?
    • Hur värderas teknikämnet ekonomiskt, statusmässigt, schemamässigt, lokalmässigt resp. utrustningsmässigt?
    • Finns det någon lärare med särskilt ansvar på skolan för teknikämnet? Finns en lokal arbetsplan?
    • Vilka typer av skrivna läromedel används och vilka behövs det mer av?
    • Vilka lokaler används för teknikämnet, samt hur lämpliga är dessa för ändamålet?
    • Finns adekvat utrustning tillgänglig på skolan för teknikundervisningen och ur bör utrustningen kompletteras?
    • Hur fungerar teknikundervisningen på skolan totalt sett, samt om man behandlar teknikämnet på bästa möjliga sätt på skolan.
    • Når skolan upp till de nationella målen för år 5 resp. år 9?
    • Integreras teknikämnet med andra skolämnen?
    • Vad styr deras undervisning i teknikämnet?
    • Finns det möjligheter finns att stärka deras arbete i teknikämnet, t.ex. genom medverkan av industri/näringsliv?
    • Kommer elevernas teknikintresse att stimuleras om de praktiska inslagen i undervisningen ökade?
    • Finns det behov av fort- och vidareutbildning inom teknikämnet?

    Nedanstående frågor är relaterade till såväl kön som invandrarbakgrund:

    ·        Hur väl når de eleverna i undervisningen i teknikämnet?

    ·        Hur bedöms elevernas intresse för teknikämnet jämfört med tekniska sammanhang i allmänhet?

    • Dominerar betygsintresse över teknikintresse?
    • Vilken betydelse har gruppåverkan (kamraters attityder och förväntningar) resp. föräldrapåverkan på elevernas teknikintresse?
    • Vilken påverkan har teknikämnet på elevernas teknikintresse?

     

    Slutligen:

     

    • Behöver teknikämnets karaktär förändras för att stimulera elevernas teknikintresse?
    • Tror lärarna att teknikämnet påverkar eleverna positivt att välja tekniska eller naturvetenskapliga studier i gymnasieskolan?
  • 120.
    Prasad, Sathyaveer
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Halim, Humam
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Evaluation of a Near Field Scanner for TRP and Radiation Pattern Measurements of GSM Mobile Phones2009In: 3RD EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION, IEEE conference proceedings, 2009, p. 2122-2126Conference paper (Other academic)
    Abstract [en]

    In this paper a new tool for estimation of the radio performance of terminal antennas in terms of Total Radiated Power, TRP is tested and evaluated. The tool is known as Lab Express and is developed by the Canadian company EMSCAN.  The results from measurements performed with the Lab Express are compared with of the radiation patterns and total radiated power (TRP) estimates, measured with a CTIA approved Satimo SG24 chamber.

    The TRP and radiation pattern measurements are performed on 10 commercially available mobile phones at GSM 900 and GSM 1800 frequency bands. The dependency of the measured TRP on the positioning of the mobile phone on EMSCAN is also tested. Our results indicate that the TRP measured with Lab Express is well correlated with the results obtained from the Satimo SG24 chamber even though the Lab Express equipment seem to over estimate the TRP with on average about 4dB at 900MHz and about 1.3dB at 1800MHz.

  • 121.
    Prasad, Sathyaveer
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Medawar, Samer
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Estimation of the Rician K-factor in Reverberation Chambers for Improved Repeatability in Terminal Antenna Measurements2008In: 30th Annual Symposium of the Antenna Measurement Techniques Association (AMTA), Boston, Mass.: AMTA-2008 , 2008, p. 6-Conference paper (Other academic)
    Abstract [en]

    The in-network performance of the mobile phone depends highly on the terminal antennas. Their performance may reduce the coverage and the capacity of the whole network. Hence, an antenna measurement method that accurately emulates the in-network radio environment is much desired.

    The reverberation, or mode-stirred, chamber is a cavity resonator with a high Q factor used for testing the performance of terminals and terminal antennas in a controlled field environment. In order to create a homogeneous field inside the chamber, emulating an isotropic multipath environment, mode stirrers are used.

    The Rician K-factor is a statistical parameter that describes the field distribution in the chamber and is defined as the ratio of the unstirred to stirred field components in the chamber. This K-factor varies from zero to infinity. In order to be able to accurately repeat a measurement performed in a reverberation chamber it is, hence, of greatest importance to accurately determine the Rician K-factor from said measurements.

    In this paper, a statistical model for the electromagnetic fields in reverberation chamber is reviewed for a Line of Sight (LOS) environment. An Estimator of the Rician K-factor is derived and its accuracy is verified.

  • 122.
    Prasad, Sathyaveer
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ramachandran, Prasad
    University of Gävle, Center for RF Measurement Technologies.
    Mean Effective Gain Measurements of Mobile Phones using the Telia Scattered Field Measurement Method2007In: RFMTC07: The Conference on RF Measurement Technology for State of The Art Production and Design, Stockholm: KTH , 2007, p. 7-Conference paper (Other academic)
    Abstract [en]

    In this paper, the measurement procedure for estimation of mobile phone antenna performance is presented. This is achieved by considering the Mean Effective Gain (MEG) relative to half-wavelength dipole antenna as the figure of merit. MEG of 13 commercially available mobile phones is measured using the Telia Scattered Field (TSFM) Method in one channel at each of the GSM900 and DCS1800 bands. The measurements of these handsets are carried out in Rayleigh fading environment, characterized by the XPR obtained from the propagation measurements. The statistics of the measured envelope distribution have been fitted to Rayleigh, Rice and Weibull distributions with corresponding goodness of fit analysis. Further, the investigation focuses on the variation of MEG with the surrounding environment of propagation and also with the position of the mobile phone.

  • 123.
    Prasad, Sathyaveer
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Ramachandran, Prasadh
    Glazunov, Andres Alayon
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    EVALUATION OF THE TELIA SCATTERED FIELD MEASUREMENT METHOD FOR ESTIMATION OF IN-NETWORK PERFORMANCE OF MOBILE TERMINAL ANTENNAS2007Conference paper (Other academic)
    Abstract [en]

    In this paper we present and evaluate a method for estimation of in-network performance of mobile terminal antennas developed by the Swedish telecom operator Telia.

    The Telia Scattered Field Measurement (TSFM) Method is intended to give a better estimate of the performance of the mobile terminal antenna as in an in-network fading scenario. The parameter measured from the TSFM method is referred to as the Scattered Field Measurement Gain, SFMG, i.e. the Mean Effective Gain, MEG, measured relative to a half wave dipole antenna. MEG includes the radiation pattern of the mobile terminal antenna as well as an estimate of polarization and directional losses that occur due to the propagation environment.

    In this study it is found that the TSFM method provides a good measure of the in-network performance of the mobile terminal antenna. Furthermore, it is shown that the SFMG measured with this method is found to be well correlated with the Total Radiated Power Gain, TRPG, or radiation efficiency. This suggests that the Total Radiated Power, TRP, may be a good measure of the in-network performance of mobile terminal antennas if measured with proper adjustment to the antenna and propagation channel mismatch.

  • 124. Puscov, J.
    et al.
    Chilo, José
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Experience of a small UAV with a commercial flight computer2006In: NATO/FOI Workshop on Autonomy in UAV-systems, 2006Conference paper (Other (popular science, discussion, etc.))
  • 125.
    Rabén, Hans
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Receiver Front-End Design for WiMAX/LTE in 90 nm CMOS: Receiver Front-End Design for WiMAX/LTE in 90 nm CMOS2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 126.
    Ramachandran , Prasadh
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Bengtsson , Olof
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Impedance determination of terminal power amplifiers for optimal antenna matching using load-pull method2009In: 2009 IEEE International Workshop on Antenna Technology: iWAT2009 : "Small Antennas and Novel Metamaterials", Santa Monica, California, 2009Conference paper (Refereed)
    Abstract [en]

    In this paper we present a single tuner based load-pull method for characterization of optimal antenna load impedance in mobile terminals. In the proposed load-pull set-up the mobile terminal itself is used as a source. The presented method can provide valuable data for antenna design since it determines the optimal impedance at the antenna connector/pad taken into account the full output circuitry of the mobile terminal. It reveals the modification of the power amplifier, PA, output impedance caused by the presence of saw filter, antenna switch, and transmission line possibly present between the PA and the antenna. With the presented method it is not only possible to characterize the optimum antenna impedance to present to the terminal in different bands and channels but also to reveal the impedance miss-match sensitivity for each channel.

  • 127.
    Ramachandran, Prasadh
    University of Gävle, Center for RF Measurement Technologies. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Method and Arrangement for Matching an Antenna2008Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A method and an arrangement for matching the antenna of a radio device in transmitting condition. The antenna impedance in the output of the power amplifier of a transmitter is adjusted by means of a π-shaped reactive matching circuit, the component values of which can be selected from a relatively wide array of the alternatives. The component values are selected by means of the multiple-way switches, which only are located in the transverse branches of the matching circuit. The switches are set (706) by the control unit, input variables of which being the SWR value provided by the directional coupler, the operating band used each time and a value of the transmitting power. The matching is based on an adjusting process to be executed at regular intervals, in which process the control unit tries different combinations of the switch states and finally selects (710) the combina¬ tion, which brings the lowest SWR value. In the beginning of the adjusting process the control unit reduces (705), on grounds of the current values of the input variables, the number of the combinations to be tried. The antenna matching maintains relatively good, although the internal output impedance of the amplifier and the impedance from the output towards the antenna would strive to differ from each other for external reasons, a band changing or a change in the outptut power.

  • 128.
    Ramachandran, Prasadh
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Milosavljevic, Zlatoljub
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Adaptive Matching Circuitry for Compensation of Finger Effect on Handset Antennas2009In: EuCAP 2009: 3rd European Conference on Antennas and Propagation, Berlin, 2009, p. 801-804Conference paper (Refereed)
    Abstract [en]

    In this paper we present and evaluate the effect of hand on terminal antenna and discuss a method to compensate for the mismatch. A dual band PIFA was used in this study. The presence of the hand was observed to cause 2-6dB loss in efficiency in low-band and 2-4dB loss in highband.In this study we propose a dynamic antenna matching (DAM) technique to improve matching level that can improve the total efficiency of the antenna by 2 – 4dB compared to the mismatched case.

  • 129.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Software for determining the third order Volterra kernels of radio frequency power amplifiers2005Report (Other academic)
    Abstract [en]

    Software for determining the third order Volterra kernels of radio frequency power amplifiers is presented. The background theory is included, the source code in Matlab is appended and some examples are given as illustrations and for verification of the code.

  • 130.
    Rönnow, Daniel
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Digital predistortion of radio frequency power amplifiers using a Kautz-Volterra model2006In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 13, p. 780-782, article id 20060460Article in journal (Refereed)
    Abstract [en]

    A digital predistortion algorithm for radio frequency power amplifiers based on orthonormal basis functions is presented. It has the same general properties as a Volterra model, but fewer parameters. Experimentally, using a 3.84 MHz wide signal at 2.14 GHz, the adjacent channel power was suppressed 12 to 15 dB, which was 5 to 7 dB more than a polynomial predistorter.

  • 131.
    Rönnow, Daniel
    et al.
    WesternGeco AS, Oslo, Norway.
    Wisell, David
    Ericsson AB, Gävle, Sweden.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Three-Tone Characterization of Nonlinear Memory Effects in Radio Frequency Power Amplifiers2007In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, no 6, p. 2646-2657Article in journal (Refereed)
    Abstract [en]

    A stepped three-tone measurement technique based on digitally modulated baseband signals is used in characterizing radio-frequency power amplifiers (PAs). The bandwidths of the stepped measurement were 8.8 MHz for the input signal and 26.4 MHz for the output signal. A PA designed for third-generation mobile telecommunication system was analyzed. The amplitude and phase of the third-order Volterra kernel were determined from the identified intermodulation products. The properties of the Volterra kernel along certain paths in the 3-D frequency space were analyzed and compared to some box models for nonlinear systems. The main symmetry of the third-order Volterra kernel of this PA was found to be of the type given by the cascaded quadratic nonlinearities with a linear filter in between (a Hammerstein-Wiener system), and frequency dependence, i.e., memory effects, was found to be due to the effects at the baseband.

  • 132.
    Sayago Montilla, David
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    The Plausibility of implementing Receive Antenna Diversity in the Downlink of CDMA450 system2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 133.
    Siddiq, Musab
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Synthetic Instruments: an overview2008In: Nordic Test Forum 2008, 2008Conference paper (Refereed)
  • 134.
    Stenumgaard, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. The Swedish Defence Research Agency (FOI), Linköping, Sweden .
    On radiated emission limits for pulsed interference to protect modern digital wireless communication systems2007In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 49, no 4, p. 931-936Article in journal (Refereed)
    Abstract [en]

    Present international standards for maximum levels of unintentional radiated emission from electronic devices are developed to protect analog communication services. In this paper, we propose a set of measurement bandwidths and electric field strength levels that could be used as radiated emission limits for future radiated emission standards, based on the RMS detector, in order to protect modern digital communication services. The emission limits determined fall below the present levels for commercial electronics but above the present limits for military-specified electronics. The results in this paper give a useful picture of the order of the size of radiated electric field limits to protect modern digital communication systems/services.

  • 135.
    Stenumgaard, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Radiated Emission from Personal Computers: a Safety Risk for TETRA Systems?2008In: 2008 International Symposium on Electromagnetic Compatibility - EMC Europe, IEEE , 2008, p. 1-3Conference paper (Refereed)
  • 136.
    Stenumgaard, Peter
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Chilo, José
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wireless Machine-to-Machine Communications in Industrial Environments2009In: Electronic Environment 2009, 2009, p. 72-75Conference paper (Other academic)
  • 137. Vestling, Lars
    et al.
    Bengtsson, Olof
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Eklund, Klas-Håkan
    Olsson, Jörgen
    Increased efficiency in RF-power SOI-LDMOS transistors2009In: EUROSOI 2009 - Conference Proceedings: Fifth Workshop of the Thematic Network on Silicon-On-Insulator, Technology, Devices and Circuits, 2009, p. 117-118Conference paper (Refereed)
    Abstract [en]

    The effect of substrate resistivity on efficiency in high-power operation of high-frequency SOI-LDMOS transistors is for the first time investigated using computational load-pull simulations. Identical SOI-LDMOS transistors have been studied on different substrate resistivities. Their highpower performance has been compared to previous investigations concerning the off-state ROUT to high-efficiency relation. It is shown that albeit high off-state ROUT is a good indication it may not always be sufficient for high efficiency operation. The bias and frequency dependency of the coupling through the substrate makes a more detailed on-state analysis necessary. It is shown that very low resistivity and high resistivity SOI-substrates both result in high efficiency at the studied frequency and bias-point. It is also shown thata normally doped, medium resistivity, substrate results in significantly lower efficiency.

     

     

     

     

     

     

     

  • 138. Vestling, Lars
    et al.
    Bengtsson, Olof
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Olsson, Jörgen
    High Efficiency using Optimized SOI-Substrates2008In: Gigahertz Symposium 2008: Abstract Book, Göteborg: Chalmers , 2008, p. 94-94Conference paper (Other academic)
    Abstract [en]

    Abstract—The effect of the substrate resistivity on

    the efficiency for high-frequency SOI-LDMOS transistors

    is studied using computational load-pull simulations.

    It is shown that very low resistivity and

    high resistivity SOI-substrates both result in high

    efficiency. It is also shown that a normally doped,

    medium resistivity, substrate results in significantly

    lower efficiency.

  • 139.
    Winter, Tomas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Potentialstyrning i mellanspänningsnät: kalibrering av restströmskompensering och isolationsprovning2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The background to this work is the introduction of the RCC Ground Fault Neutralizer in countries that earlier have used solidly earthed medium voltage networks. The RCC Ground Fault Neutralizer is a protection system that is capable of handling earth faults without disconnecting the feeder. Since some equipment, that cannot be immediately replaced, only can withstand the full voltage for a limited time, the operating time of the system needs to be limited. This is also true during the commissioning when calibrating the system means that the voltage against earth needs to be increased.

    The primary purpose with this work is to create a possibility to automatically calibrate the settings for the inverter that are used when reacting to an earth fault. A goal with the new automatic calibration is that it should be faster than a preset time per phase. A second goal is to create a more user friendly control of the neutral voltage using the inverter. The purpose of this is to prepare the system for the possibility that PD measurement in combination with the control of the neutral voltage offers. This way isolation defects could be found and possibly also delayed.

    The solution that was chosen was as simple as possible and is a combination of setting the inverter to a calculated value and proportional control. This was implemented in the service software which is normally used for commissioning, surveillance and manual control.

    The solution was proven to be good enough to clear the goal that was set up for this work. The first tests were performed against a net model. After the solution had proven to be successful in the net model more test where performed on a system installed in a real substation. Also the PD control software was tested but only in the net model and because higher voltages is needed to test PD activity no real test with PD was performed. Hopefully this new software can be used to further develop this idea in the future.

  • 140.
    Wisell, David
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Measurement techniques for characterization of power amplifiers2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis a sampling time domain measurement system primarily intended for measurements on radio frequency power amplifiers is discussed. The need for such a measurement system is established. Impairments due to non-ideal measurement instruments are discussed as well as methods to compensate for these impairments. Techniques to improve upon the raw measurement performance of the measurement instruments with regard to bandwidth, dynamic range, linear and nonlinear distortion are discussed. A method to simultaneously find the phase and amplitude ripple of a vector signal generator and a vector signal analyzer is presented. The method is verified with extensive measurements.

    Two techniques, frequency stitching and Zhu's generalized sampling theorem, to extend the effective measurement bandwidth of the measurement system is discussed and evaluated with measurements. They are both found to be able to extend the effective bandwidth for measurements of output signals of nonlinear power amplifiers with more than five times.

    The measurement system is used for sampled input - output measurements of power amplifiers and the obtained data are fitted to different behavioral power amplifier models including memory. Some different behavioral models are evaluated and compared for different kinds of power amplifiers. A neural network model and extensions to the well-known parallel Hammerstein model are specifically discussed. The parallel Hammerstein model are also used together with frequency stitching and Zhu's generalized sampling theorem.

    A general hardware and software structure of a versatile measurement system based on virtual instruments for measurements on power amplifiers is discussed in some detail. Special attention is given to the software architecture and to the concepts of hardware and software reusability.

    An automated, fast, accurate and production-friendly method for two-tone power and frequency sweep measurements, including measurement of the phase of the intermodulation products in addition to the amplitude, is also presented.

  • 141.
    Wisell, David H.
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Ericsson Telecom AB, Stockholm, Sweden; Signal Processing Lab, Royal Institute of Technology, Stockholm, Sweden.
    Rudlund, Björn
    Racomna AB, Uppsala, Sweden; Omicron AB, Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. WesternGeco AS, Asker, Norway.
    Characterization of memory effects in power amplifiers using digital two-tone measurements2007In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, no 6, p. 2757-2766Article in journal (Refereed)
    Abstract [en]

    In this paper, a novel method to measure the amplitude and phase of two-tone third-order intermodulation products generated in a high-power amplifier is presented. The method is based on the sampled input and output signals of the amplifier. The presented measurement setup and the associated algorithms for the calculation of the amplitudes and phases are considerably faster and simpler than the current methods. By making use of the sampled input and output signals of the amplifier and the signal processing techniques, the need for a nonlinear reference, a tunable attenuator, and a phase shifter in the existing measurement setups is eliminated, which makes it simple and easy to use. Hence, this is a substantial simplification of the measurement setup compared to what has been reported earlier. The proposed measurement setup is also suitable for fast automated measurements, which is of interest for many applications that are both laboratory and production oriented. In addition, a method to increase the bandwidth of the measured signal is used to overcome the bandwidth limitation set by the Nyquist criteria for sampled systems. Measurements are done on two base-station high-power amplifiers and are found to be in agreement with theory and reference measurements.

  • 142.
    Wisell, David
    et al.
    Ericsson AB.
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Simultaneous Measurement of Transmitter and Receiver Amplitude and Phase Ripple2009Report (Other academic)
    Abstract [en]

    This paper describes a method to simultaneously measure the amplitude and phase ripple of two band pass linear systems in cascade by changing the center frequency for one of the systems. Extensive measurements are presented to support the theory. The method has a wide applicability for measurements on RF power amplifiers, transmitters, receivers, etc. The accuracy of the method is in the order of a few hundredths of a dB and one degree for most realistic measurement set-ups.

  • 143.
    Wisell, David
    et al.
    Ericsson AB, Gävle, Sweden.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Derivation of a Behavioral RF Power Amplifier Model with Low Normalized Mean-Square Error2007In: Proceedings of European Microwave Week 2007, 8-12 October 2007, Munich, Germany, 2007, p. 1283-1286Conference paper (Refereed)
  • 144. Wisell, David
    et al.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Validation of Behavioral Radio Frequency Power Amplifier Models2007In: RF Measurement Technology Conference, Gävle 11-12 September, 2007Conference paper (Other academic)
  • 145. Wisell, David
    et al.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Validation of Behavioural Power Amplifier Models Using Coherent Averaging2005In: Proc. Gigahertz 2005: Uppsala, Sweden, 2005, p. 318-321Conference paper (Other academic)
  • 146. Wisell, David
    et al.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A General Evaluation Criteria for Behavioral PA Models2007In: 69th ARFTG Microwave measurement conference, Honolulu, HI, USA, 2007, p. 251-255Conference paper (Refereed)
  • 147. Wisell, David
    et al.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wideband characterization of a Doherty amplifier using behavioral modeling2006In: 67th ARFTG Conference 2006, 2006, p. 190-199Conference paper (Refereed)
    Abstract [en]

    A Doherty amplifier was investigated using behavioral amplifier modeling techniques. A measurement system for simultaneous wide bandwidth (>100 MHz) and large dynamic range (similar to 70 dBc ACLR) sampled measurements that are needed for the behavioral modeling is presented. Both the measurement system and the performance of the Doherty amplifier are described. The findings are that the well known and widely used parallel Hammerstein model, also denoted the memory polynomial model, is well suitable also for modeling and predistortion of Doherty amplifiers, and that a Doherty amplifier can be designed with only minor memory effects. This is seen in the modeling error, which is reduced by 13 dB, compared with a constant gain, using a memoryless polynomial model and only 6 dB further by adding memory to the model.

  • 148. Wisell, David
    et al.
    Jaldén, Joakim
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Behavioral Power Amplifier Modeling Using the LASSO2008In: I²MTC 2008 – IEEE International Instrumentation and Measurement Technology Conference Victoria, Vancouver Island, Canada, May 12–15, 2008, p. 1864-1867Conference paper (Refereed)
    Abstract [en]

    In this paper we use regularization, in the form of

    the LASSO, as identification procedure in order to find the

    parameters of the parallel Hammerstein model for behavioral

    power amplifier modeling. It is shown that the LASSO chooses a

    subset of the parameters of the parallel Hammerstein model in a

    systematic way and thereby reduces the number of model

    parameters while maintaining the performance. The values of the

    parameters are also smaller than when the ordinary least-squares

    algorithm is used for the parameter extraction since the LASSO

    imposes a limit on the L1-norm of the parameters. Thus, the

    problem with large, and sometimes very large, parameters that is

    often encountered in behavioral power amplifier modeling is

    avoided. Experimental results from measurements on a power

    amplifier intended for the 3G WCDMA system is provided to

    support the theory.

  • 149.
    Wisell, David
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. KTH; Ericsson AB.
    Keskitalo, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Ericsson AB.
    A behavioral power amplifier model that includes the average power level2018In: 2006 68th ARFTG Conference on Measurement for Emerging Technologies, ARFTG 2006, IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    In this paper a behavioral power amplifier model that incorporates the average input power level is proposed. The result is a model that can accurately predict the output signal of the amplifier for all input power levels. The model is validated using measurements on a radio base station power amplifier and it is found that it does indeed has improved generalization capabilities with regard to input power level compared to previous models. 

  • 150.
    Wisell, David
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Ericsson AB, Stockholm, Sweden; Signal Processing Laboratory, Royal Institute of Technology, Stockholm, Sweden.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Westerngeco AS, Asker, Norway..
    Händel, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Signal Processing Laboratory, Royal Institute of Technology, Stockholm, Sweden.
    A technique to extend the bandwidth of an RF power amplifier test bed2007In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, no 4, p. 1488-1494Article in journal (Refereed)
    Abstract [en]

    In this paper, a method for increasing the bandwidth of a test bed for dynamic characterization of power amplifiers (PAs) is described. The technique is readily implemented using commercially available instruments, which makes it suitable for, e.g., production testing. The bandwidth extension technique is combined with coherent averaging of the measurements in order to simultaneously increase the bandwidth and dynamic range of the test bed. The errors in the obtained wideband signal are also estimated. The method is evaluated experimentally on a base station PA for the third-generation wideband code division multiple access system and on a Doherty amplifier. A tenfold increase in bandwidth to a total of 144 MHz and a more than 10-dB increase in dynamic range to 78 dB were obtained in practice. In addition, the obtained wideband signal is used for behavioral amplifier modeling.

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