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  • 51.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Horvath, György
    Lindblad, Thomas
    Olsson, Roland
    A Flexible Electronic Nose for Odor Discrimination Using Different Methods of Classification2009In: IEEE NPSS Real Time Conference 2009, New York: IEEE , 2009, p. 317-320Conference paper (Refereed)
    Abstract [en]

    Ovarian cancer is one of the leading causes of death front cancer in women. The lifetime risk is around 1.5%, which makes it the second most common gynecologic malignancy (the first one being breast cancer). To have a definitive diagnose, a surgical procedure is generally required and suspicious areas (samples) will be removed and sent for microscopic and other analysis. This paper describes the result of a pilot study in which an electronic nose is used to "smell" the aforementioned samples, analyze the multi-sensor signals and have a close to real-time answer on the detection of cancer. Besides being, fast. the detection method is inexpensive and simple. Experimental analysis using real ovarian carcinoma samples shows that the use of proper algorithms for analysis of the multi-sensor data front the electronic nose yielded surprisingly good results with more than 77% classification rate. The electronic nose used in this pilot study was originally developed to be used as a "bomb dog" and can distinguish between e.g. TNT. Dynamex. Prillit. However, it was constructed to be a flexible multi-sensor device and the individual (16) sensors call easily be replaced/exchanged. This is suggestive for further investigations to obtain even better results with new, specific sensors. In another pilot experiment, headspace of an ovarian carcinoma sample and a control sample were analyzed using gas chromatography-mass spectrometry. Significant differences in chemical composition and compound levels were recorded, which would explain the different response obtained with the electronic nose.

  • 52.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Horvath, György
    Department of Oncology, Sahlgrenska University Hosp. Gothenburg.
    Lindblad, Thomas
    Department of Physics, Royal Institute of Technology.
    Olsson, Roland
    Department of Computer Science, Ostfold University College, N-1757 Halden, Norway.
    Electronic Nose Ovarian Carcinoma Diagnosis Based on Machine Learning2009In: Advances in Data Mining: Applications and Theoretical Aspects, Berlin: Springer Berlin / Heidelberg , 2009, p. 13-23Chapter in book (Refereed)
  • 53.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Jabor, Abbas
    Liszka, L.
    Eide, Å.J.
    Lindblad, T.
    Bergkvist, L.P.
    Stahlsten, T.
    Andersson, B.L.
    Karasalo, I.
    Cederholm, A.
    Filtering and extracting features from infrasound data2005In: Real Time Conference, 2005, 2005, p. 451-455Conference paper (Refereed)
  • 54.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Jabor, Abbas
    Liszka, L.
    Ejde, Å.J.
    Lindblad, Th.
    Persson, L.
    Infrasonic and Seismic Signals from Earthquake and Explosions in Arequipa, Perú2006In: Western Pacific Geophysics Meeting., 2006Conference paper (Other academic)
  • 55.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Jabor, Abbas
    Royal Institute of Technology, Department of Physics, Stockholm, Sweden.
    Lizska, Ludwik
    Swedish Institute of Space Physics in Umeå, Sweden.
    Eide, Åge J.
    Ostfold University College, Halden, Norway.
    Lindblad, Thomas
    Royal Institute of Technology, Department of Physics, Stockholm, Sweden.
    Obtaining “images” from iron objects using a 3-axis fluxgate magnetometer2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 580, no 2, p. 1105-1109Article in journal (Refereed)
    Abstract [en]

    Magnetic objects can cause local variations in the Earth's magnetic field that can be measured with a magnetometer. Here we used tri-axial magnetometer measurements and an analysis method employing wavelet techniques to determine the "signature" or "fingerprint" of different iron objects. Clear distinctions among the iron samples were observed. The time-dependent changes in the frequency powers were extracted by use of the Morlet wavelet corresponding to frequency bands from 0.1 to 100 Hz.

  • 56.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Karlsson, Carl
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ängskog, Per
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Elofsson, Carl
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Stenumgaard, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Characterizing electromagnetic interference in vicinity to a railway freight train2009In: Proc. IEEE Int. Symp. on EMC/EMECO, Saint-Petersburg, 2009, p. 23-26Conference paper (Refereed)
  • 57.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Karlsson, Carl
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ängskog, Per
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Stenumgaard, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    APD measurements for characterization and evaluation of radio interference in steel mill2009In: Proceedings IEEE nternational Symposiumon EMC, Kyoto, 2009, p. 625-628Conference paper (Refereed)
  • 58.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Karlsson, Carl
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ängskog, Per
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Stenumgaard, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    EMI disruptive effect on wireless industrial communication systems in a paper plant2009In: Proc. IEEE EMC Symp. Austin-Texas, 2009, p. 221-224Conference paper (Refereed)
    Abstract [en]

    It is well known that industrial and factory environments present considerable challenges for wireless communications. Because every industrial environment is different, and may offer a unique set of obstacles to effective wireless communication, a site characterization is needed at first step in determining improvements of existent wireless technologies to increase the reliability. In this work electric field strength and APD measurements have been performed to characterize electromagnetic interference in an industrial paper plant. Common characteristics of the industrial environments affecting wireless communication were identified. Additionally, results show high interference levels at the frequencies for the DECT band 1880-1890 MHz. The interference level is correlated to the working mode of the electrical engines used in the process.

  • 59.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Karlsson, Carl
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ängskog, Per
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Stenumgaard, Peter
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Impulsive noise measurement methodologies for APD determination in M2M environments2009In: Proc. IEEE EMC Symp. Austin-Texas, 2009, p. 151-154Conference paper (Refereed)
    Abstract [en]

    Wireless communications in industrial environments are maintained under persistent adverse conditions, such as noise, fading and many electromagnetic interference sources. These electromagnetic interferences exhibit usually impulsive characteristics and it can seriously degrade the performance of the current wireless systems. Over the last few years, the amplitude probability distribution (APD) had been formally written into CISPR16 as a measure of the emitted electromagnetic energy from electrical equipment. In this approach we present two APD measurement methods. The first method based on 12-bit A/D converter and the second one based on in-phase and quadrature components of the impulsive noise at frequencies between 20 and 3000 MHz. Electromagnetic interference measurements in three different industrial environments were performed using the developed methods with promising results.

  • 60.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Kinser, Jason
    Lindblad, Thomas
    Discrimination of Nuclear Explosions Sites by Seismic Signals using Intrinsic Mode Functions and Multi-Modal Data Space2008In: IEEE International Geoscience and Remote Sensing Symposium, 2008, p. 895-898Conference paper (Refereed)
  • 61.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindblad, Thomas
    Data Acquisition and Digital Filtering for Infrasonic Records on Active Volcanoes2007In: Sensors & transducers, ISSN 1726-5479, Vol. 77, no 3, p. 1058-1064Article in journal (Refereed)
  • 62.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindblad, Thomas
    Obtaining images from iron objects using a 3-axis fluxgate magnetometer2006In: International Conference on Imaging Techniques in Subatomic Physics, Astrophysics, Medicine, Biology and Industry, 2006Conference paper (Refereed)
    Abstract [en]

    Magnetic objects can cause local variations in the Earth's magnetic field that can be measured with a magnetometer. Here we used triaxial magnetometer measurements and an analysis method employing wavelet techniques to determine the "signature" or "fingerprint" of different iron objects. Clear distinctions among the iron samples were observed. The time-dependent changes in the frequency powers were extracted by use of the Morlet wavelet corresponding to frequency bands from 0.1 to 100 Hz. (c) 2007 Elsevier B.V. All rights reserved.

  • 63.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Royal Institute of Technology, Stockholm, Sweden.
    Lindblad, Thomas
    Royal Institute of Technology, Stockholm, Sweden.
    Real-Time Signal Processing of Infrasound Data Using 1D Wavelet Transform on FPGA Device2007In: 2007 15TH IEEE-NPSS REAL-TIME CONFERENCE, VOLS 1 AND 2, Piscataway, NJ: IEEE , 2007, p. 170-174Conference paper (Refereed)
    Abstract [en]

    Infrasound is a low frequency acoustic phenomenon typically in the frequency range 0.01 to 20 Hz. Data collected from infrasound microphones are presented online by the infrasound monitoring system operating in Northern Europe, Swedish-Finnish Infrasound Network (SFIN). Processing the continuous flow of data to extract optimal feature information is important. Using wavelet decomposition as a tool for removing noise from the real-time signals is an alternative. The purpose of this paper is to present the design and FPGA implementation of Discrete Wavelet Transform (DWT) for real-time infrasound data processing, in which only two FIR filters, a high-pass and a low-pass filter, are used. With the filter reuse method and techniques such as pipeline, basic operations, by the VHDL on the platform QUARTUS II, FPGA simulation and implementation are fulfilled. This implementation takes advantage from the low sampling rate used by the infrasound monitoring system that is only 18 Hz.

  • 64.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindblad, Thomas
    Wireless Data Acquisition System Using Bluetooth Technology for Infrasonic Records2008In: International Scientific Journal of Computing, ISSN 1727-6209, Vol. 7, no 2, p. 18-21Article in journal (Refereed)
  • 65.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindblad, Thomas
    Olsson, Roland
    Hansen, Stig-Erland
    Comparison of three feature extraction techniques to distinguish between different infrasound signals2007In: Progress in pattern recognition, London: Springer , 2007, p. 75-82Chapter in book (Other (popular science, discussion, etc.))
  • 66.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Olsson, Roland
    Hansen, Stig-Erland
    Lindblad, Thomas
    Classification of Infrasound Events with Various Machine Learning Techniques2007In: CITSA 2007 / CCCT 2007: The 4th International Conference on Cybernetics and Information Technologies, Systems and Applications jointly with The 5th International Conference on Computing, Communications and Control Technologies, 2007, p. Vol. II, 191-195Conference paper (Refereed)
  • 67.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Schluter, Andreas
    KTH.
    Lindblad, Thomas
    KTH.
    Development of a high-resolution wireless sensor network for monitoring volcanic activity2009In: Geoscience and Remote Sensing / [ed] Pei-Gee Peter Ho, InTech , 2009, p. 53-74Chapter in book (Other academic)
  • 68.
    Chilo, José
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Thomas, Lindblad
    Hardware implementation of 1D wavelet transform on an FPGA for infrasound signal classification2008In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 55, no 1, part 1, p. 9-13Article in journal (Refereed)
  • 69.
    Cortas Nordlander, Maria
    et al.
    Vasaskolan, Gävle.
    Nordlander, Edvard
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A Study of Students’ Ability to Solve Text-Based Mathematical Problems with Irrelevant or Superfluous Information2008In: Mathematical Views, MAVI 14: Strobl/Salzburg, Austria, May 2008, 2008Conference paper (Refereed)
    Abstract [en]

    A limited quantitative survey has been performed in order to study the capability of students to solve text-based mathematical problems containing irrelevant or superfluous information, as well as their ability to scrutinize text and sort out the relevant information. The students took a written test with text-based problems of different amount of irrelevant or superfluous information. The capability of understanding such problems was investigated versus degree of maturity and gender. Obtained results indicate a noticeable correlation between the occurrence of irrelevant or superfluous information and ability of solving the problems. Furthermore, the results show that the degree of maturity, expressed in terms of age, has a clear influence on the results. This study has not revealed any significant difference between genders as regards ability of sorting out the relevant information.

  • 70.
    Cortas Nordlander, Maria
    et al.
    Vasaskolan, Gävle.
    Nordlander, Edvard
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Influence of Student’s Attitudes and Beliefs on the Ability of Solving Mathematical Problems with Irrelevant Information2009In: Beliefs and attitudes in mathematics education: new research results / [ed] Jürgen Maasz and Wolfgang Schlöglmann, Rotterdam: Sense Publishers , 2009, p. 165-178Chapter in book (Other academic)
    Abstract [en]

    A limited quantitative survey has been performed in order to study how attitudes, beliefs and feelings of students may influence the ability of solving text-based mathematical problems containing irrelevant information. The survey is also analyzing their capability of scrutinizing texts and sorting out relevant information.

    The students took a written test with text-based problems of different amount of irrelevant information. The capability of understanding such problems was investigated versus degree of mathematical maturity and gender. Obtained results indicate a noticeable correlation between the occurrence of irrelevant information and the ability of solving the problems. Furthermore, attitudes, beliefs, and the degree of mathematical maturity, expressed in terms of age, have a clear influence on the results. On the other hand, this study has not revealed any significant difference between genders as regards the capability of solving text-based problems with irrelevant information.

     

  • 71.
    Deng, Kai
    et al.
    University of Gävle. University of Gävle, Department of Technology and Built Environment. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ma, Minjie
    University of Gävle. University of Gävle, Department of Technology and Built Environment. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    THE STUDY AND IMPLEMENTATION OF MEANDER-LINE ANTENNA FOR AN INTEGRATED TRANSCEIVER DESIGN2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    This thesis focuses on the design and evaluation of the meander-line antenna geometry. One standard meander-line antenna and other two non-standard meander antennas have been studied. These printed antennas are discussed with the goal of identifying which is suitable for use in a miniaturized wireless transceiver design and which is able to provide the better performance using minimal Printed Circuit Board (PCB) space. In a word, the main objective is to characterize tradeoffs and identify which antenna provides the best compromise among volume, bandwidth and efficiency.

    The performance of each antenna is evaluated based on return loss, operational bandwidth, and radiation pattern characteristics. During our measurement, return loss is measured by reading the S11-port reflection coefficient on Vector Network Analyzer (VNA). This coefficient can be used to characterize how well the antenna is able to be efficiently fed. Operational bandwidth is measured as the frequency range over which the antenna keeps the value of Voltage Standing Wave Ratio (VSWR) or equivalently has -10dB return loss. Ansoft High Frequency Structure Simulator (HFSS) is used to simulate expected characteristics which are resonant frequency, bandwidth, VSWR, and radiation pattern. HFSS is used to provide a good guide for the antenna design before the actual prototype is manufactured. Simulated results are compared with results of measurement to point out the differences and help demonstrate the practical effects on antenna performance. Radiation pattern are measured to illustrate the effects of antenna miniaturization. All the above measurements are done in the anechoic chamber.

  • 72.
    El Rashid, Mohamad
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Study of Multiport Antenna Systems on Terminals for WLAN: MIMO Technology2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Using more than just on antenna can significantly speed up the data rate in a wireless communication system. These systems are commonly referred to as Diversity- and MIMO-systems. Due to tight volume restriction for the antennas, e.g. in a mobile phone, electromagnetic coupling between the antennas will degrade the capacity of the wireless system and lower the coverage.

    In the proposed thesis, a thorough study of Ethertronics’ standard antennas will be established in which the antennas will be used in a multiport system, e.g. MIMO. The thesis will be strongly related to Ethertronics’ engagement in Chase and therefore also dependent on the latest progresses on MPA (Multiport Analyzer) developed in Chase. The thesis will result in a working methodology how to use MPA plus design-, location- and orientation rules for the standard antennas used in a multiport system.

  • 73.
    EL-Rashid,, Jihad
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Tawk, Youssef
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Current Distribution in High RF Power Transistors2007Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To obtain the power levels required from high RF power transistors, the size of the chip has often to be made so large that inductance of electrical connections inside the package cannot be neglected. This may have the effect that various parts of the transistor chip are not connected exactly parallel, i.e. drain and gate voltages and currents densities will not be the same on different parts of the chip. This may result in degraded output power and efficiency. The same effect may occur when more than one chip are connected in parallel in a transistor package to obtain even higher output power.Often the connections to the transistor package are approximated as a number of electrical point connections (normally three: gate, drain, source); meaning that each of them can be described by a single electrical potential and current. In reality, they may be large enough that voltage and current distributions have to be considered. These distributions will be affected by different mountings of the transistor and other connected components.In this work, the LDMOS power transistor MRF6S21140HR3 was modeled using the segmentation method in high frequency signal simulation HFSS which is a 3D Full-Wave Electromagnetic Field Simulation, and utilized the advanced design system ADS to find a parameterized lumped model. Both the electromagnetic and lumped models showed consistent results. Non-ideal parallel connection of sub-transistors on chip is very important, but further studies are needed for definite conclusion. It was verified through modeling that non ideal parallel connection of different chips in the package does have an effect; the effect however is quiet small which proves that the signal is slightly non-uniformly distributed between the three chips in the package. External connection to PCB (drain connection is considered in this work) can effectively be taken as a point connection to some approximation. The electrical behavior of the modeled transistor was studied through the design of a class B power amplifier in order to estimate the importance of performance degradation due to non-ideal parallel connections and how these non ideal connections degrade efficiency and output power. The modeled transistor can deliver a maximum output power of 147 watts and efficiency of 65%. We have also studied the current distribution between the three chips in a three stage class B power amplifier. Again, the difference in the current distribution between the three chips turned out to be quiet small. All these results are presented through this work. The final conclusion regarding the current distribution between multichips cannot be made just based on these simulation results. The next step should be aimed at considering other effects, the thermal effect for example, in order to know exactly whether it is uniformly or not uniformly distributed.

  • 74.
    Feng, Xin Mei
    et al.
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Olsson, J.
    Centre for Human Studies of Foodstuffs, Uppsala University, Uppsala, Sweden.
    Swanberg, M.
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Schnürer, J.
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Image analysis for monitoring the barley tempeh fermentation process2007In: Journal of Applied Microbiology, ISSN 1364-5072, E-ISSN 1365-2672, Vol. 103, no 4, p. 1113-1121Article in journal (Refereed)
    Abstract [en]

    Aims: To develop a fast, accurate, objective and nondestructive method for monitoring barley tempeh fermentation. Methods and Results: Barley tempeh is a food made from pearled barley grains fermented with Rhizopus oligosporus. Rhizopus oligosporus growth is important for tempeh quality, but quantifying its growth is difficult and laborious. A system was developed for analysing digital images of fermentation stages using two image processing methods. The first employed statistical measures sensitive to image colour and surface structure, and these statistical measures were highly correlated (r = 0.92, n = 75, P < 0.001) with ergosterol content of tempeh fermented with R. oligosporus and lactic acid bacteria (LAB). In the second method, an image-processing algorithm optimized to changes in images of final tempeh products was developed to measure number of visible barley grains. A threshold of 5 visible grains per Petri dish indicated complete tempeh fermentation. When images of tempeh cakes fermented with different inoculation levels of R. oligosporus were analysed the results from the two image processing methods were in good agreement. Conclusion: Image processing proved suitable for monitoring barley tempeh fermentation. The method avoids sampling, is nonintrusive, and only requires a digital camera with good resolution and image analysis software. Significance and Impact of the Study: The system provides a rapid visualization of tempeh product maturation and qualities during fermentation. Automated online monitoring of tempeh fermentation by coupling automated image acquisition with image processing software could be further developed for process control.

  • 75.
    Fraz, Hamza
    et al.
    Georgia Tech..
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Kenney, J. S.
    Georgia Tech..
    Sperlich, R.
    Texas Instruments.
    Prediction of Harmonic Distortion in ADCs using dynamic Integral Non-Linearity model2009In: Behavioral Modeling and Simulation Workshop, 2009. BMAS 2009. IEEE, 2009, p. 102-107Conference paper (Refereed)
    Abstract [en]

    This paper investigates the application of dynamic, Integral Non-Linearity (INL) model of Analog-to-Digital Converters (ADC) to predict the harmonic distortion in pipelined ADCs. The device used to validate the model is Texas Instruments' ADS6129; a 12-bit, 250 MSPS1 pipelined ADC. The performance of the model is measured using single tones in the first Nyquist zone, with an amplitude ranging between −1 dBFS2 and −46 dBFS. Total Harmonic Distortion (THD) and Spurious Free Dynamic Range (SFDR) are used as metrics to compare the performance of the model to the actual ADC. The results indicate that a model for High Code Frequency (HCF) INL is essential for correct prediction of distortion for input signals with small amplitudes. The results also suggest that dynamic INL models offer an effective method to model the distortion in ADCs until Nyquist frequency only. Beyond Nyquist frequency, the non-linear effects of Track and Hold (T/H) start manifesting and the INL model can no longer account for all the distortion seen at the output of ADCs.

  • 76.
    Glans, Mikael
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Utveckling av styrsystem för EMC-kammare2009Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to develop a control system for measuring electromagnetic compability (EMC). This has meant that a controller designed around an ATmega8 microcontroller has been manufactured and programmed. It has also meant the development of a comprehensive control software in the program MATLAB. The control system has been tested with satisfactory results and can now, monitor and control measurements of the EMC-type.

  • 77.
    Händel, Peter
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Royal Institute of Technology, Signal Processing Lab, Stockholm, Sweden.
    Björsell, Niclas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Royal Institute of Technology, Signal Processing Lab, Stockholm, Sweden.
    Jansson, Magnus
    Royal Institute of Technology, Signal Processing Lab, Stockholm, Sweden.
    Model based dynamic characterization of analog-digital converters at radio frequency2007In: ISSPA 2007 9th International symposium on signal processing and its applications. Vols 1-3, 2007, p. 1403-1408Conference paper (Refereed)
    Abstract [en]

    A dynamic characterization of analog-digital converter in-tegral nonlinearity (INL) is considered. When using a plu-rality of test frequencies in the measurement set-up, thedynamic errors of the converter are characterized. TheINL is modeled by low and high code components - LCFand HCF, respectively. The LCF and HCF are parameter-ized and a least squares method is derived for the estima-tion of the parameter values from obtained measurements.A closed form solution to the estimation problem is de-rived and its performance is illustrated by a numerical ex-ample. The proposed method is believed to be fruitful inwide-band characterization of analog-digital converters atradio frequency, and thus of importance for the evaluationof modern and future wireless communication systems.

  • 78.
    Händel, Peter
    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.
    Jansson, Magnus
    Medawar, Samer
    Modeling the dynamics of analog-digital-converters at radio frequency2007In: RF Measurement Technology Conference, Gävle 11-12 September 2007, 2007Conference paper (Other (popular science, discussion, etc.))
  • 79.
    Händel, Peter
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies. Royal Institute of Technology, Signal Processing Lab, ACCESS Linnaeus Centre, Stockholm, Sweden.
    Prasad, Sathyaveer
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies. Royal Institute of Technology, Signal Processing Lab, ACCESS Linnaeus Centre, Stockholm, Sweden.
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. University of Gävle, Center for RF Measurement Technologies.
    Maximum likelihood estimation of reverberation chamber direct-to-scattered ratio2009In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 45, no 25, p. 1285-1286Article in journal (Refereed)
    Abstract [en]

    The exact maximum likelihood estimator of the direct-to-scattered ratio of the Rician channel in a reverberation chamber is derived and its performance analysed. It is shown that the estimator obeys a non-central F-distribution, the mean value and variance of which are derived. For well stirred chambers, it is shown that the systematic error in the estimated ratio may be significant.

  • 80.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A Measure to Characterize the Impact of Sets of Scientific Papers2008Report (Other academic)
    Abstract [en]

    A figure-of-merit for quantifying a comparable scientific value ranking the output of a set researchers work is proposed. The method is based on the Garfield Factor (GF) and thus related to the expected number of citations rather than the real ones. The measure allow comparisons of the scientific outputs between different sets of scientists where some papers are joint works between the comparative sets or between constellations with other sets. It has the advantages of having a rather small time-lag and that it is comparable between different subject categories. The measure is very easy to calculate and is complementing the existing indices or measures in an adequate way.

  • 81.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Behavioural Modelling of Radio Frequency Power Amplifiers: An Evaluation of Some Block Structure and Neural Network Models2005Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This work considers behavioral modelling of radio frequency power amplifiers. Due to the use of modern digital modulation methods power amplifiers are nowadays subjected to signals having a considerable bandwidth and a fast changing envelope. This means that traditional quasi-memoryless amplitude-to-amplitude (AM/AM) and amplitude-to-phase (AM/PM) characteristics are no longer enough to describe and model the behavior of power amplifiers, neither can they be successfully used for linearization.

    In this thesis, sampled input and output data are used for identification and validation of some block structure models with memory. The time-discrete Volterra model, the Wiener model, the Hammerstein model, and the radial-basis function neural network are all identified and compared with respect to in-band and out-of-band errors. Two different signal types, i.e. multi tones and noise, with different powers, peak-to-average ratios, and bandwidths have been used as input to the amplifier. Two different power amplifiers were investigated, one designed for the third generation mobile telecommunication systems and one for the second generation.

    A stepped three-tone measurement technique based on digitally modulated baseband signals is presented. The third-order Volterra kernel were determined from identified inter-modulation products. The properties of the Volterra kernel along certain parts in the three dimensional frequency space were analysed and compared to the Wiener and Hammerstein models.

  • 82.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Parameter-reduction for Volterra models in radio frequency power amplifier applications2007In: RF Measurement Technology Conference, Gävle 11-12 September, 2007Conference paper (Other academic)
  • 83.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Radio Frequency Power Amplifiers: Behavioral Modeling, Parameter-Reduction, and Digital Predistortion2009Book (Other academic)
  • 84.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Radio Frequency Power Amplifiers: Behavioral Modeling, Parameter-Reduction, and Digital Predistortion2007Doctoral thesis, comprehensive summary (Other academic)
  • 85.
    Isaksson, Magnus
    et al.
    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.
    A Kautz-Volterra Behavioral Model for RF Power Amplifiers2006In: IEEE MTT-S International Microwave Symposium Digest, 2006, 2006, p. 485-488Conference paper (Refereed)
    Abstract [en]

    A new type of behavioral power amplifier (PA) model, a discrete-time Kautz-Volterra (KV) model, is presented. In the model a priori knowledge of the system properties in terms of different poles for different nonlinear orders is used, which is needed for modeling nonlinear and linear memory effects in PAs. An accurate model can thus be achieved with a small number of parameters. Simulated results of parallel Hammerstein and Wiener structures and from modeling the behavior of a PA are presented

  • 86.
    Isaksson, Magnus
    et al.
    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.
    A Parameter-Reduced Volterra Model for Dynamic RF Power Amplifier Modeling based on Orthonormal Basis Functions2007In: International Journal of RF and Microwave Computer-Aided Engineering, ISSN 1096-4290, E-ISSN 1099-047X, Vol. 17, no 6, p. 542-551Article in journal (Refereed)
    Abstract [en]

    A nonlinear dynamic behavioral model for radio frequency power amplifiers is presented. It uses orthonormal basis functions, Kautz functions, with complex poles that are different for each nonlinear order. It has the same general properties as Volterra models, but the number of parameters is significantly smaller. Using frequency weighting the out-of-band model error can be reduced. Using experimental data it was found that the optimal poles were the same for different input powers and for the different nonlinear orders. The optimal poles were also the same for direct and inverse models, which could be explained theoretically to be a general property of nonlinear systems with negligible linear memory effects. The model can be used as either a direct or inverse model with the same model error for power amplifiers with negligible linear memory effects.

  • 87.
    Isaksson, Magnus
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wisell, David
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Extension of the Hammerstein Model for Power Amplifier Applications2004In: 63rd ARFTG Conference Digest - Spring 2004, 2004, p. 131-137Conference paper (Refereed)
  • 88.
    Isaksson, Magnus
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Royal Institute of Technology, Signal Processing Lab, Stockholm, Sweden.
    Wisell, David
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Royal Institute of Technology, Signal Processing Lab, Stockholm, Sweden; Ericsson AB, Gävle, Sweden.
    Eng, Anders
    Syntronic AB, Gävle, Sweden.
    Rönnow, Daniel
    WestemGeco AS, Asker, Norway.
    A Study of a Variable-Capacitance Drain Network's Influence on Dynamic Behavioral Modeling of an RF PA2007In: 69th ARFTG Microwave measurement conference, Honolulu, HI, USA, 2007, p. 112-116Conference paper (Refereed)
    Abstract [en]

    An investigation of the complex-valued parameters of two different dynamic behavioral models due to changes in the drain decoupling network of a PA has been performed. The study is based on complex-envelope measurements on a real PA. The complex coefficients of the parallel Hammerstein (PH) and the optimal pole placements of the Kautz-Volterra (KV) models are analyzed. It is concluded that the parameters follow smooth, predictable functions and that the KV poles give a robust description of the PA's memory effects compared with the PH model.

  • 89.
    Isaksson, Magnus
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wisell, David
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    A Comparative Analysis of Behavioral Models for RF Power Amplifiers2006In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 54, no 1, p. 348-359Article in journal (Refereed)
    Abstract [en]

    A comparative study of nonlinear behavioral models with memory for radio-frequency power amplifier (PAs) is presented. The models are static polynomial, parallel Hammerstein (PH), Volterra, and radial basis-function neural network (RBFNN). Two PAs were investigated: one was designed for the third-generation (3G) mobile telecommunication systems and one was designed for the second-generation (2G). The RBFNN reduced the total model error slightly more than the PH, but the error out of band was significantly lower for the PH. The Volterra was found to give a lower model error than did a PH of the same nonlinear order and memory depth. The PH could give a lower model error than the best Volterra, since the former could be identified with a higher nonlinear order and memory depth. The qualitative conclusions are the same for the 2G and 3G PAs, but the model errors are smaller for the latter. For the 3G PA, a static polynomial gave a low model error as low as the best PH and lower than the RBFNN for the hardest cross validation. The models with memory, PH, and RBFNN, showed better cross-validation performance, in terms of lower model errors, than a static polynomial for the hardest cross validation of the 2G PA.

  • 90.
    Isaksson, Magnus
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wisell, David
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Behavioural Amplifier Modelling Using Sampled Complex Envelope Measurement Data2005In: Proc. Gigahertz 2005, 2005, p. 213-216Conference paper (Refereed)
  • 91.
    Isaksson, Magnus
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wisell, David
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik. Ericsson AB, Gävle, Sweden.
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Nonlinear Behavioral Modeling of Power Amplifiers Using Radial-Basis Function Neural Networks2005In: 2005 IEEE MTT-S International Microwave Symposium Digest, 2005, p. 1967-1970Conference paper (Refereed)
    Abstract [en]

    A radial-basis function neural network (RBFNN) is proposed for modeling the dynamic nonlinear behavior of RF power amplifiers. In the model the signal's envelope is used. The model requires less training than a model using both IQ-data. Sampled input and output signals from a power amplifier for 3G were used in the identification and validation. The RBFNN is compared with a parallel Hammerstein model. For a memory depth of one sample the RBFNN gives a better model, in- and out-of-band; for three samples the RBFNN reduces the in-band error more while the Hammerstein model reduces the error out-of-band more.

  • 92.
    Isaksson, Magnus
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wisell, David
    Rönnow, Daniel
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Wide-Band Dynamic Modeling of Power Amplifiers Using Radial-Basis Function Neural Networks2005In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 53, no 11, p. 3422-3428Article in journal (Refereed)
  • 93. Johansson, Ted
    et al.
    Bengtsson, Olof
    University of Gävle, Department of Technology and Built Environment. Elektronik.
    Nordlander, Edvard
    University of Gävle, Department of Technology and Built Environment. Elektronik. University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Rydberg, Anders
    RF-power SiGe transistors for cellular base stations: base profile design1999In: RVK99, 1999Conference paper (Other academic)
  • 94.
    Karlsson, Carl
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ängskog, Per
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ferrer Coll, Javier
    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.
    Stenumgaard, Peter
    FOI.
    Outdoor electromagnetic interference measurements in industrial environments2009Conference paper (Refereed)
  • 95.
    Kingdon, Patricia
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Nordlander, Edvard
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Methods to study the influence of recruiting campaigns on pupils’ notions of technology and technology education2009In: Strengthening the Position of Technology Education in the Curriculum: Proceedings PATT 22 Conference / [ed] Arien Bekker, Ilja Mottier, Marc J. de Vries, 2009, p. 270-278Conference paper (Refereed)
    Abstract [en]

    This paper will discuss the methodology to be used in a newly started Ph.D. study about the Image of the Engineering Student and Engineering. The aim of the study is to deconstruct the images of the engineering student and the engineering profession occurring in recruiting campaigns of the Royal Institute of Technology (KTH). The campaigns can be seen as a part of a discourse. According to Foucault, a discourse is statements more or less uniformly produced. In the Foucault concept, the practice is also of interest in the context. Practice can be described as human activities which bring forth what can be said within a certain institution, e.g., the Royal Institute of Technology. There is no strict boundary between the discourse and the practice, and, hence, the concept discoursive practice will be useful to describe the under-lying restrictions and possibilities of what can be said and done within a practice.

    The campaigns are parts of an ongoing larger pedagogic project with the purpose of influencing young people’s notions of technology and technology education. According to Foucault, power is strictly nothing more than its exercise which is practised by control and administrative techniques. In this context, power is brought to the campaigns. This fact does not mean that individuals are victimised by the influence of campaigns, but, nevertheless, they have to act against or adjust to the discourse to which they are exposed.

    A suitable methodical approach to the subject implies content analysis and discourse analysis. In this paper, suitable tools and variables for the analysis will be discussed. For example, significant variables are gender and technical specialization in an engineering profession or engineering education. The variables will be organised in a coding system. Other types of variables which will be coded are themes. In this respect, socio-economic status is an example of a relevant theme, which possibly has to be divided into sub-themes.

  • 96.
    Krishna, Pothula Hari
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Cánovas, Victor
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Ramachandran, Prasadh
    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.
    Multi-band PIFA for combined 3G and DVB-H Terminals: a preliminary study2007In: 2007 IEEE International Workshop on Antenna Technology: Small & Smart Antennas, Metamaterials and Applications : iWAT 2007, S²AMA : conference proceedings : Cambridge, UK, March 21-23, 2007, Piscataway, NJ: IEEE , 2007, p. 439-442Conference paper (Refereed)
    Abstract [en]

    Based on the work by Ciais et. al, a small, efficient and low profile Planar Inverted-F antenna with multi-band operations for the use in mobile telephones has been studied. The antenna was designed using a High Frequency Structure Simulator, HFSS, built and verified. In order to increase the bandwidth of the antenna from the original design it is further optimized by frequency tuning using the shorts of different parasitic element. The resulting antenna operates over two wide bands from (710-1200) MHz and from (1750-2170) MHz, covering five cellular bands and the upper part of the UHF-band allowing it to be used in terminals combining cellular and DVB-H operations.

  • 97.
    Landin, Per
    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.
    Keskitalo, Niklas
    University of Gävle, Center for RF Measurement Technologies.
    Tornblad, Olof
    Infineon Technologies.
    Sideband asymmetries in RF Power LDMOS Before and After Digital Predistortion2009Conference paper (Other academic)
    Abstract [en]

     The merging of the fields of RF engineering and signal processing has introduced concepts such as behavioral modeling and enabled digital linearization schemes for wireless devices, such as power amplifiers (PAs). Despite that this process has been going on for a number of years much work remains to be done. The links between physical behavior and mathematical models are far from well-understood as are the optimum strategies for device design. This study focus on digital predistortion properties of a one-stage PA consisting of a power transistor mounted in a test fixture. The device under test (DUT) is an Infineon PTF210451E, a 45W transistor intended for usage in the frequency bands 2010-2025 MHz and 2110-2170 MHz. The test fixture is also designed by Infineon Technologies.  The signal types used in the measurements are single and double carrier wideband code division multiple access (WCDMA) signals. The double carrier WCDMA signals have tone-spacings of 5, 10 and 15 MHz. Normal two-tone measurements are also presented. 

  • 98.
    Landin, Per Niklas
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    On Radio Frequency Behavioral Modeling: Measurement Techniques, Devices and Validation Aspects2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Radio frequency (RF) power amplifiers (PA) are still the most troublesome part of a wireless system due to their inherent nonlinearity, low powerefficiency and high distortions. Better tools are needed to understand and correct the undesirable behavior. Some of these tools are behavioral models. A behavioral model is often thought of as a black box with some inputs and some outputs. In the case here these inputs are sampled signals which means that the modeling amounts to finding a mathematical relationship between the input signal(s) and the output signal(s).

    This thesis considers some requirements for behavioral modeling of said systems by presenting methods for general performance evaluation and improvement by considering a frequency weighted error criterion. A high performance measurement system is also needed. The performance of the available system is compared to the performance of a well recognized system, the large signal network analyzer (LSNA). The results show that the existing measurement system can extract behavioral models with the same performance as the LSNA and can give lower performance validation errors.

    Still the need for higher bandwidths drives the measurement systems to the limits, especially the digital parts. By utilizing the so called Zhu-Frank generalized sampling theorem, behavioral modeling of a PA is done by using data acquired at a sampling rate lower than the Nyquist rate. Models of a PA are extracted and the performance is evaluated using the normalized mean square error (NMSE) criterion. For prediction and correction of the output signals the stability of the models regarding changes must be investigated. One such study considering controlled variations on the output load of the PA is done and both the predictive and corrective capabilities of the models are evaluated. The predictive capability gets up to 7 dB worse measured as adjacent channel error power ratio (ACEPR) and the corrective, as digital predistortion, gets up to 13 dB worse measured as adjacent channel power ratio (ACPR).

  • 99.
    Landin, Per Niklas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Bengtsson, Olof
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Power Amplifier Behavioural Model Mismatch Sensitivity and the Impact on Digital Predistortion Performance2009In: Proc. 39th European Microwave Conference (EuMC), IEEE conference proceedings, 2009, p. 338-341Conference paper (Refereed)
    Abstract [en]

    This paper presents an investigation of poweramplifier behavioural model performance sensitivity to in-bandreflections. The measurement system and model extractionprocess is presented together with the results and an analysis ofthe effect of parameter variations in a digitally predistortedsystem. A load-pull system is used together with a digitalbaseband model extraction system to identify the impact onmodelling performance. The results show that the modelperformance varies greatly with in-band reflection magnitudeand phase on the amplifier output. It is also shown that a digitalpredistortion based on a model extracted at matched conditions,where it gives an excellent improvement of 20 dB in adjacentchannel leakage ratio (ACLR), gives a poor improvement of 7 dBfor miss-matched conditions with as low reflections as Γ=0.2(return loss 14 dB). This indicates that in-band reflections needto be considered and adaptive predistortion used also for lowVSWR system like base-stations for telecommunication.

  • 100.
    Landin, Per Niklas
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Fager, Christian
    Chalmers.
    Isaksson, Magnus
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Andersson, Kristoffer
    Chalmers.
    Power Amplifier Behavioral Modeling Performance Comparison of the LSNA and the Modulation-Domain System2008In: 72nd ARFTG Microwave Measurement Symposium, 2008, Portland, OR., 2008, p. 73-78Conference paper (Refereed)
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