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  • 1.
    Andersen, O.
    et al.
    Ericsson AB.
    Wisell, David
    Ericsson AB.
    Keskitalo, Niclas
    Högskolan i Gävle, Radio Center Gävle. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Measurement of ACLR with high dynamic range2008Inngår i: IEEE MTT-S International Microwave Symposium Digest, Atlanta, GA, 2008, s. 273-277Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this paper a method to overcome the insufficient dynamic range of RF measurement instruments, i.e. signal generators and spectrum analyzers, for distortion measurements on feedforward and other highly linear amplifiers, is discussed. A circuit board is designed, built and verified. Its performance is found to be superior to traditional methods using filters, both from a technical performance and flexibility standpoint as well as from an economic view. ACLR measurements for WCDMA signals can be done well below -70 dBc using the produced circuit board. © 2008 IEEE.

  • 2.
    Andersen, Olav
    et al.
    Ericsson.
    Björsell, Niclas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik. Högskolan i Gävle, Radio Center Gävle.
    Keskitalo, Niclas
    Högskolan i Gävle, Radio Center Gävle. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    A Test-Bed Designed to Utilize Zhu’s General Sampling Theorem to Characterize Power Amplifiers2009Inngår i: Instrumentation and measurement technology conference 2009 I2MTC '09 IEEE, Singapore, 2009, s. 201-204Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Characterizing power amplifiers require test set-ups with performance superior to the power amplifiers. A commonly used method is to use an IQ-demodulator. However, problem arises due to imperfections in the demodulator such as IQ-imbalance; an alternative method is to use a direct down converter to intermediate frequency. The drawback then is the limited bandwidth. However, the required bandwidth of the ADC does not need to be exceptional. According to Zhu’s general sampling theorem is it enough to sample the output signal at the Nyquist rate of the input. However, even though the required sampling rate is reduced the demands on the analog bandwidth remains. Unfortunately, commercially available instruments such as vector signal analyzers can not be used for this purpose since their analog bandwidth is too small. In this paper a test-bed is designed to utilize the Zhu’s general sampling theorem. The RF front-end has frequency range of 500 MHz – 2.7 GHz and a bandwidth of 1 GHz. All performance data are verified with measurements.

  • 3.
    Andersen, Olav
    et al.
    Ericsson AB, Gävle Sweden.
    Wisell, David
    Ericsson AB, Gävle, Sweden.
    Keskitalo, Niclas
    Ericsson AB, Gävle, Sweden.
    Stenvard, Patrik
    Ericsson AB, Gävle, Sweden.
    Cost effective high performance modular instrumentation, signal generation and signal analysis for future mobile communication systems2007Inngår i: 2007 IEEE Autotestcon: proceedings. Vol. 1 AND 2, 2007, s. 660-668Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A decrease in life cycle cost is a key issue for testing of mobile communication systems. The rapid development and edge technology requires high performance instruments and state of the art measurement technology. It is desired to use virtual/synthetic instruments and put the measurement technology in software independent of hardware, i.e. software driven measurements. Increased flexibility and modularization, both in hardware and software, are requirements to support the cost decrease. The hardware basis is signal generation and signal analysis.

    In this paper state of the art signal generation and signal analysis capabilities are demonstrated in a modular and flexible architecture. A direct IF synthesis is used to generate 1 WideBand Code-Division Multiple Access (WCDMA) carrier with more than 72 dB Adjacent Carrier Leakage Ratio (ACLR) 2 carrier with more than 68 dBc ACLR over a total bandwidth of 100 MHz. The signal analysis capabilities, ACLR performance, for a WCDMA carrier is better than -70 dBc and for a continuous wave better than -85 dBc over a bandwidth of 42.5 MHz. The critical down converter in the set up doesn’t degrade the performance.

  • 4.
    Andersen, Olav
    et al.
    Ericsson Telecom AB, Gävle, Sweden.
    Wisell, David
    Ericsson Telecom AB, Stockholm, Sweden.
    Staenvard, Patrik
    Ericsson Telecom AB, Gävle, Sweden.
    Keskitalo, Niclas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik. Högskolan i Gävle, Radio Center Gävle.
    Extending the Bandwidth and Dynamic Range of Old RF Instruments to Meet State-of-the-Art Performance, Using a Synthetic Instrument Approach2009Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 58, nr 2, s. 248-254Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A decrease in life cycle cost is a key issue for testing mobile communication systems. The rapid development and edge technology requires high-performance instruments and state-of-the-art measurement technology. New investments are expensive, but even older generation instruments are capable of extending their bandwidth and dynamic range to meet even the latest Third-Generation Partnership Project (3GPP) cellular measurement requirements by the addition of external hardware using a synthetic instrument approach. The novelty of this paper is the high performance on the most crucial parameters, i.e., the dynamic range and bandwidth achieved by only replacing some parts of the legacy instrument. Moreover, the demonstrated direct IF synthesis has a high degree of novelty at wide modulation bandwidths. It is desired to use virtual/synthetic instruments and make the signal processing in the software independent of the hardware, i.e., software-defined measurements (SDMs). In this paper, a state-of-the-art experimental setup for signal generation and signal analysis is demonstrated. A direct IF synthesis is used to generate a wideband code-division multiple-access (WCDMA) carrier with more than 72-dB adjacent carrier leakage ratio (ACLR) up to 12 parallel carriers with more than 68-dBc ACLR over a total bandwidth of 100 MHz. The signal analysis capabilities (e.g., ACLR performance) for a WCDMA carrier is better than -70 dBc and for a continuous wave better than -85 dBc over a bandwidth of 42.5 MHz. The critical RF downconverter in the setup is carefully designed not to degrade the dynamic range performance.

  • 5.
    Landin, Per
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Keskitalo, Niklas
    Högskolan i Gävle, Radio Center Gävle.
    Tornblad, Olof
    Infineon Technologies.
    Sideband asymmetries in RF Power LDMOS Before and After Digital Predistortion2009Konferansepaper (Annet vitenskapelig)
    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. 

  • 6.
    Landin, Per Niklas
    et al.
    Högskolan i Gävle, Radio Center Gävle.
    Nader, Charles
    Högskolan i Gävle, Radio Center Gävle.
    Björsell, Niclas
    Högskolan i Gävle, Radio Center Gävle.
    Isaksson, Magnus
    Högskolan i Gävle, Radio Center Gävle.
    Wisell, David
    Ericsson AB.
    Händel, Peter
    Högskolan i Gävle, Radio Center Gävle.
    Andersen, Olav
    Ericsson AB.
    Keskitalo, Niclas
    Högskolan i Gävle, Radio Center Gävle.
    Wideband Characterization of Power Amplifiers Using Undersampling2009Inngår i: 2009 IEEE MTT-S International Microwave Symposium, Boston: IEEE MTT , 2009, s. 1365-1368Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper a radio frequency power amplifier is measured and characterized by the use of undersampling based on the generalized Zhu-Frank sampling theorem. A test system has been designed allowing the bandwidth of the stimuli signal to be 100 MHz in the characterization process. That would not be possible with any vector signal analyzer on the market. One of the more challenging problem within the proposed concept is the model validation process. Here, two different techniques for model validation are proposed, the multitone and the spectrum scan validation methods.

  • 7.
    Nader, Charles
    et al.
    Högskolan i Gävle, Radio Center Gävle.
    Altahir, Hibah
    Högskolan i Gävle, Radio Center Gävle.
    Andersen, Olav
    Ericsson AB.
    Björsell, Niclas
    Högskolan i Gävle, Radio Center Gävle.
    Condo, Edith
    Högskolan i Gävle, Radio Center Gävle.
    Keskitalo, Niclas
    Högskolan i Gävle, Radio Center Gävle.
    De La Rosa, Hector
    Freescale Semiconductor Nordic AB.
    Automated multidimensional characterization of power amplifier for design and production2009Inngår i: 2009 IEEE Instrumentation and Measurement Technology Conference Proceedings, Singapore: I&M Society , 2009, s. 144-148Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Designing, optimizing and producing modern power amplifiers (PA) requires new and fast RF (radio frequency) measurement techniques capable of characterizing its real behavior. Power amplifiers are a truly multidimensional device where many desired performance parameters are contradictory to each other. This is especially true for the generation of modern communication PAs that require high efficiency, high linearity as well as high bandwidth. This paper presents a software-defined measurement setup for fast and cost efficient multidimensional measurements based on highly accurate standard instruments and a PC. The test bed as well as the graphical user interface is presented along with a demonstration of its functionality. During tuning of tank networks, drain quiescent current, and bias conditions, 3-dimensional graphs can be selected for the most appropriate axes of trade-off parameters to display a true behavior of the PA under test subjected to real-world or close to real-world signals. The measurement system offers the possibility to monitor envelope-tracking dynamic power consumption up to 100 MHz plus the possibility to use high crest factors.

  • 8.
    Nader, Charles
    et al.
    Högskolan i Gävle, Radio Center Gävle. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Landin, Per Niklas
    Högskolan i Gävle, Radio Center Gävle. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Björsell, Niclas
    Högskolan i Gävle, Radio Center Gävle. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    Högskolan i Gävle, Radio Center Gävle. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Wisell, David
    Ericsson AB.
    Händel, Peter
    KTH, EES, Signal processing lab.
    Andersen, Olav
    Ericsson AB.
    Keskitalo, Niclas
    Högskolan i Gävle, Radio Center Gävle.
    Wideband Power Amplifiers Characterization by Undersampling: Zhu-Frank Sampling Theorem2009Konferansepaper (Annet vitenskapelig)
  • 9. Wisell, David
    et al.
    Isaksson, Magnus
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Keskitalo, Niclas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    A General Evaluation Criteria for Behavioral PA Models2007Inngår i: 69th ARFTG Microwave measurement conference, Honolulu, HI, USA, 2007, s. 251-255Konferansepaper (Fagfellevurdert)
  • 10. Wisell, David
    et al.
    Isaksson, Magnus
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Keskitalo, Niclas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Rönnow, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Wideband characterization of a Doherty amplifier using behavioral modeling2006Inngår i: 67th ARFTG Conference 2006, 2006, s. 190-199Konferansepaper (Fagfellevurdert)
    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.

  • 11.
    Wisell, David
    et al.
    Ericsson.
    Stenvard, Patrik
    Ericsson.
    Hansebacke, Anders
    Ericsson.
    Keskitalo, Niclas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Considerations when Designing Virtual Instruments2009Rapport (Annet vitenskapelig)
    Abstract [en]

    In this paper the software and hardware structure of a virtual instrument measurement system is discussed. The focus is on flexibility, modularity, generality and hardware independence. A software architecture that meets these requirements is proposed and discussed in some detail. The proposed software architecture has a layered structure that makes it suitable for implementation of versatile measurement systems. The measurement functionality is encapsulated in its own, hardware independent layer and communicates with its environment, e.g. physical hardware, through intermediary software components. Finally a measurement system for characterization of power amplifiers that is designed following the proposed software architecture, with software driven measurements, is implemented.

  • 12.
    Zenteno, Efrain
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Andersen, Olav
    Isaksson, Magnus
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Keskitalo, Niclas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Wisell, David
    Nonlinear Network Analysis for Modern Communication Devices and Systems2008Inngår i: 72nd ARFTG Conf. Dig., Portland, OR, 2008, s. 64-68Konferansepaper (Fagfellevurdert)
  • 13.
    Zenteno, Efrain
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Isaksson, Magnus
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Wisell, David
    Keskitalo, Niclas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för elektronik.
    Andersen, Olav
    An Envelope Domain Measurement Test Setup to Acquire Linear Scattering Parameters2008Inngår i: 72nd ARFTG Conf. Dig., Portland, OR, 2008, s. 54-57Konferansepaper (Fagfellevurdert)
1 - 13 of 13
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