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  • A low-complexity memoryless model for envelope tracking RF power amplifiers

     Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; García García, José Ángel; Ruiz Lavin, Maria de las Nieves; Marante, Reinel
    European Microwave Conference
    p. 1-4
    DOI: 10.1109/EuMC.2014.6986716
    Presentation's date: 2014-10-07
    Presentation of work at congresses

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    This paper presents a new kind of behavioral model structure for characterizing static nonlinearities in dynamically supplied RF power amplifiers. The proposed architecture is based on the combination of several basic cells and it is focused to simplify the real-time design and implementation of adaptive shaping functions devoted to improve the efficiency in systems controlled by digital signal processors with tight computational capabilities, such is the case of handsets and small-cells.

  • Highly efficient transmitter architectures

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; García García, José Angel
    Date of publication: 2014-10-01
    Book chapter

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    Control system of a miniature 12 MeV race-track microtron  Open access

     Koubychine Merkulov, Youri Alexandrovich; Blasco Argente, Vicente-pablo; Romero, Juan Antonio; Sanchez Diaz, Alexandre; Montoro López, Gabriel; Shvedunov, Vasiliy
    International Particle Accelerator Conference
    p. 3165-3167
    Presentation's date: 2014-07-11
    Presentation of work at congresses

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    A simple control system has been developed for the commissioning of a compact 12 MeV race-track microtron which is under construction at the Technical University of Catalonia. It is of modular structure and is based on LabView programs at a conventional PC and ATmega microcontrollers. Apart from modules to monitor different RTM systems it also includes an Automatic Frequency Control of the magnetron frequency and interlocks. The architecture and main features of the modules are described and results of their operation are reported. Further developments of the control system and interfaces are on the way.

  • Peak cancellation and digital predistortion of high-order QAM wideband signals for next generation wireless backhaul equipment

     López Bueno, David; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Bartzoudis, Nikolaos
    International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits
    p. 1-3
    DOI: 10.1109/INMMIC.2014.6815111
    Presentation's date: 2014-04-02
    Presentation of work at congresses

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    This paper evaluates the linearity performance in a wideband wireless backhaul transmitter when applying crest factor reduction (CFR) and digital predistortion (DPD) techniques to enhance the transmitted output power, and thus the power efficiency of the overall system, while fulfilling the communications system quality requirements and regulations. The CFR technique applied is the peak cancellation (PC), while the linearizer is based in an adaptive DPD with memory effects compensation. Order reduction techniques are also applied to mitigate the complexity of the DPD structure. The power amplifier is based in a 15 Watts GaN transistor. The test signal follows a multiband 4 channel 1024-QAM configuration (reaching up to 1 Gbps) with 12 dB of PAPR at RF and 112 MHz bandwidth (28 MHz each channel). A testbed for evaluating the PC and DPD linearization performance of the RF subsystem was deployed and experimental results are presented in this paper.

  • A dual-band outphasing transmitter using broadband class E power amplifiers

     Ruiz, Maria Nieves; Marante, Reinel; Rizo, Leysi; García, José Angel; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits
    p. 1-4
    DOI: 10.1109/INMMIC.2014.6815087
    Presentation's date: 2014-04-02
    Presentation of work at congresses

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    In this paper, a dual-band outphasing transmitter (able of operating either at 770 MHz or 960 MHz frequency bands) is presented. Two broadband RF power amplifiers (PAs) have been designed over packaged GaN HEMT devices, switching close to the nominal zero-voltage and zerovoltage-derivative class E conditions. A reactive combiner, using transmission lines of appropriate electrical lengths at both bands, together with compensating reactances, allows positioning the drain impedance loci to produce high efficiency and good dynamic range profiles. Average drain efficiency figures over 68% and 38% have been measured for WCDMA signals with a peak-to-average power ratio (PAPR) of 5.1 dB and 8.4 dB, respectively.

  • Components and Systems for Comnunications Research Group

     Mateu Mateu, Jordi; Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; Bertran Alberti, Eduardo; Berenguer Sau, Jordi; González Arbesú, José María; Rocas Cantenys, Eduard; Verdu Tirado, Jorge Andres; Hueltes Escobar, Alberto; Gelonch Bosch, Antoni; Collado Gomez, Juan Carlos
    Competitive project

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  • 3D digital predistortion for dual-band envelope tracking power amplifiers

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; López Bueno, David; García García, José Ángel
    Asia-Pacific Microwave Conference
    p. 734-736
    DOI: 10.1109/APMC.2013.6694913
    Presentation's date: 2013-11-06
    Presentation of work at congresses

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    This paper proposes a novel three-dimensional digital predistorter (3D-DPD) suitable for compensating nonlinear distortion in dual-band (DB) envelope tracking (ET) power amplifiers (PAs). By taking into account the cross-band modulation effects (due to DB operation) and the slow-envelope dependent distortion effects (due to ET), the 3D-DPD is design by properly modifying the memory polynomial (MP) behavioral model. In a first approach, the accuracy and reliability of the proposed 3D-MP model are evaluated. Finally, experimental results are shown to validate the linearization performance of the proposed 3D-DPD.

  • Transmisor polar para señales de banda ancha integrando inversión y rectificación síncrona clase E a 1 GHz

     Ruiz Lavin, Maria de las Nieves; Marante, Reinel; García García, José Ángel; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    Simposium Nacional de la Unión Científica Internacional de Radio
    Presentation's date: 2013-09-12
    Presentation of work at congresses

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    In this paper, class E inverting and synchronous rectifying functions, implemented over GaN HEMT dies, are properly integrated for the design of a 1 GHz polar transmitting architecture. Employing high-Q lumped-element passive networks, an implementation with a high power density also results. The amplitude and phase components of a 5 MHz multisine are shown to be properly recombined at the output of an 80% efficient RF power amplifier (RFPA), drain modulated by means of a resonant DC/DC converter with a peak efficiency of 77%. A frequency-modulation (FM) coding of the envelope is here proposed for the converter, resulting in a 20 MHz large-signal bandwidth and a 720 V/µSeg slew-rate value.

  • Reducción de orden en predistorsión digital para aplicaciones de banda ancha

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; López Bueno, David; Bartzoudis, Nikolaos; Payaró Llisterri, Miquel; Hourtane, Alain
    Simposium Nacional de la Unión Científica Internacional de Radio
    p. 1-4
    Presentation's date: 2013-09-11
    Presentation of work at congresses

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    This paper presents how to apply order reduction in wide-band digital predistortion (DPD) linearizers using the principal component analysis (PCA) technique. This method is tested in a wireless backhauling transmitter where four 28 MHz adjacent subcarrier transmission of M-QAM signals are considered. The DPD has to counteract not only the PA nonlinear behavior, but also its dynamics. This may results critical when considering wideband signals since the number of coefficients required to model memory effects can grow dramatically. By applying the PCA technique, the number of essential parameters can be significantly reduced. In addition, a strategy to minimize the computational cost of finding the optimal coefficients is also presented. A test-bed for evaluating the DPD linearization performance of the RF subsystem when PCA is applied was deployed and experimental results are presented in this paper.

  • Order reduction of wideband digital predistorters using principal component analysis

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; López Bueno, David; Bartzoudis, Nikolaos; Bertran Alberti, Eduardo; Payaró Llisterri, Miquel; Hourtane, Alain
    IEEE International Microwave Symposium
    p. 1-4
    DOI: 10.1109/MWSYM.2013.6697687
    Presentation's date: 2013-06-06
    Presentation of work at congresses

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    This paper presents how to apply order reduction in wide-band digital predistortion (DPD) linearizers using the principal component analysis (PCA) technique. This method is tested in a wireless backhauling transmitter where four 28 MHz adjacent subcarrier transmission of M-QAM signals are considered. The DPD has to counteract not only the PA nonlinear behavior, but also its dynamics. This may results critical when considering wideband signals since the number of coefficients required to model memory effects can grow dramatically. By applying the PCA technique, the number of essential parameters can be significantly reduced. In addition, a strategy to minimize the computational cost of finding the optimal coefficients is also presented. A test-bed for evaluating the DPD linearization performance of the RF subsystem when PCA is applied was deployed and experimental results are presented in this paper

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    Computationally efficient real-time digital predistortion architectures for envelope tracking power amplifiers  Open access

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    International journal of microwave and wireless technologies
    Vol. 5, num. 2, p. 187-193
    DOI: 10.1017/S1759078713000135
    Date of publication: 2013-03-05
    Journal article

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    This paper presents and discusses two possible real-time digital predistortion (DPD) architectures suitable for envelope tracking (ET) power amplifiers (PAs) oriented at a final computationally efficient implementation in a field programmable gate array (FPGA) device. In ET systems, by using a shaping function is possible to modulate the supply voltage according to different criteria. One possibility is to use slower versions of the original RF signal's envelope in order to relax the slew-rate (SR) and bandwidth (BW) requirements of the envelope amplifier (EA) or drain modulator. The nonlinear distortion that arises when performing ET with a supply voltage signal that follows both the original and the slow envelope will be presented, as well as the DPD function capable of compensating for these unwanted effects. Finally, two different approaches for efficiently implementing the DPD functions, a polynomial-based and a look-up table-based, will be discussed.

    This paper presents and discusses two possible real-time digital predistortion (DPD) architectures suitable for envelope tracking (ET) power amplifiers (PAs) oriented at a final computationally efficient implementation in a field programmable gate array (FPGA) device. In ET systems, by using a shaping function is possible to modulate the supply voltage according to different criteria. One possibility is to use slower versions of the original RF signal’s envelope in order to relax the slew-rate (SR) and bandwidth (BW) requirements of the envelope amplifier (EA) or drain modulator. The nonlinear distortion that arises when performing ET with a supply voltage signal that follows both the original and the slow envelope will be presented, as well as the DPD function capable of compensating for these unwanted effects. Finally, two different approaches for efficiently implementing the DPD functions, a polynomial-based and a look-up table-based, will be discussed.

  • Slew-rate and efficiency trade-off in slow envelope tracking power amplifiers

     Vizarreta Paz, Pedro Pablo; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    Frequenz
    Vol. 66, num. 11/12, p. 323-329
    DOI: 10.1515/freq-2012-0101
    Date of publication: 2012-12-12
    Journal article

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    This paper presents a study on the trade-off between the envelope's slew-rate and the drain efficiency when slower envelopes are considered to dynamically supply the power amplifier (PA). This paper discusses a method to limit the slew-rate (and consequently the bandwidth) of the signal's envelope. Moreover, since the envelope tracking (ET) technique using a slower version of the original envelope introduces nonlinear distortion, slow envelope dependent predistortion has to be also incorporated in the design of ET PAs. Experimental results showed that it is possible to find a compromise between the bandwidth and slew-rate reduction (necessary to cope with the specific envelope amplifier requirements) and the amount of drain efficiency degradation suffered due to the use of a slower version of the original envelope

    This paper presents a study on the trade-off between the envelope’s slew-rate and the drain efficiency when slower envelopes are considered to dynamically supply the power amplifier (PA). This paper discusses a method to limit the slew-rate (and consequently the bandwidth) of the signal’s envelope. Moreover, since the envelope tracking (ET) technique using a slower version of the original envelope introduces nonlinear distortion, slow envelope dependent predistortion has to be also incorporated in the design of ET PAs. Experimental results showed that it is possible to find a compromise between the bandwidth and slew-rate reduction (necessary to cope with the specific envelope amplifier requirements) and the amount of drain efficiency degradation suffered due to the use of a slower version of the original envelope.

  • Hybrid envelope amplifier for envelope tracking power amplifier transmitters

     Vizarreta Paz, Pedro Pablo; Montoro López, Gabriel; Gilabert Pinal, Pere Lluis
    European Microwave Conference
    p. 128-131
    Presentation's date: 2012-10-30
    Presentation of work at congresses

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    This paper presents an envelope tracking (ET) Power Amplifier (PA) whose architecture includes an efficient Envelope Amplifier (EA) and a bandwidth reduction algorithm suitable for real time applications. The EA consists of a hybrid amplifier combining switched and linear amplification. A bandwidth and slew-rate reduction algorithm has been incorporated in order to allow wide-band envelope amplifications. Non-linearities introduced by the Hybrid EA (HEA) and the dynamic supply are compensated with Digital Pre-Distortion. The ET PA has been tested using 64-QAM signals and commercial devices. Results show that non-linearities produced by the HEA are compensable and that the architecture provides efficiency improvements compared to the conventional linear EA.

    This paper presents an envelope tracking (ET) Power Amplifier (PA) whose architecture includes an efficient Envelope Amplifier (EA) and a bandwidth reduction algorithm suitable for real time applications. The EA consists of a hybrid amplifier combining switched and linear amplification. A band- width and slew-rate reduction algorithm has been incorporated in order to allow wide-band envelope amplifications. Non-linearities introduced by the Hybrid EA (HEA) and the dynamic supply are compensated with Digital Pre-Distortion. The ET PA has been tested using 64-QAM signals and commercial devices. Results show that non-linearities produced by the HEA are compens- able and that the architecture provides efficiency improvements compared to the conventional linear EA.

  • Resource management implications and strategies for SDR clouds

     Gómez, Ismael; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Gelonch Bosch, Antoni; Marojevic, Vuk
    Analog integrated circuits and signal processing
    Vol. 73, num. 2, p. 473-482
    DOI: 10.1007/s10470-012-9963-z
    Date of publication: 2012-09-19
    Journal article

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  • Envelope amplifier based on a hybrid series converter with the slow-envelope technique

     Cheng, P. M.; Garcia, O.; Vasic, M.; Alou, P.; Oliver, J. A.; Montoro López, Gabriel; Cobos, J. A.
    IEEE Energy Conversion Congress and Exposition
    DOI: 10.1109/ECCE.2012.6342420
    Presentation's date: 2012-09-15
    Presentation of work at congresses

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    High frequency dc-dc switching converters are used as envelope amplifiers in RF transmitters. The dc-dc converter should operate at very high frequency to track an envelope in the MHz range to supply the power amplifier. One of the circuits suitable for this application is a hybrid topology composed of a switched converter and a linear regulator in series that work together to adjust the output voltage to track the envelope with accuracy.

  • Transmisor outphasing en UHF usando amplificadores clase E a GaN HEMT

     Marante, Reinel; García García, José Ángel; Ruiz Lavin, Maria de las Nieves; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    Simposium Nacional de la Unión Científica Internacional de Radio
    Presentation's date: 2012-09-13
    Presentation of work at congresses

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    A Chireix outphasing transmitter at UHF band is presented in this paper, based on class E RF power amplifiers. As recently proved in [1], properly transforming the load modulation path, imposed by the non-isolated combiner, into fundamental frequency impedan ce values at the device drain terminals as close as possible to those assuring zero voltage switching condition, good efficiency values may be kept along a significant output power range. A lumped element implementation of the amplifiers and the combiner, together with the use of GaN HEMTs, allowed controlling the output power over a 6 dB range with an efficiency value over 60%. Experiments with asymmetrical two tones, conceived as a discrete spectrum signal with a 1:4 envelope variation, have shown the capability of the arch itecture to be linearized using digital predistortion (DPD). In order to reproduce a spectrally efficient communication signal, with nulls in the envelope, a hybrid control strategy was employed, combining the outphasing between branches with amplitude variations of both RF excitation signals for the lower range of the envelope. Average drain efficiency and PAE values of 63% and 60.3% respectively have been measu red, for a 11.8 W and 5.06 dB PAPR WCDMA signal, while m eeting ACPR specifications.

  • Envelope tracking amplification with reduced slew-rate and bandwidth envelopes

     Vizarreta Paz, Pedro Pablo; Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; Bertran Alberti, Eduardo; Berenguer Sau, Jordi; Gelonch Bosch, Antoni; García García, José Ángel
    Simposium Nacional de la Unión Científica Internacional de Radio
    Presentation's date: 2012-09-13
    Presentation of work at congresses

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    This paper presents an Envelope Tracking Pow- er Amplifier whose architecture includes a Hybrid Envelope Amplifier (HEA) and an algorithm to adapt the envelope’s characteristics to the HEA’s limitations. The HEA attempts to combine the high efficiency of a switched amplifier with the wide band capabilities of a linear amplifier. A modified Slew Rate (SR) reduction algorithm cope with the bandwidth and SR limitations of the HEA. On the other hand, the non-linearities introduced by this Envelope Amplifier (EA) and by the dynamic supply are compensated using Digital Pre-Distortion. Results show that these non-linearities are compensable and that the architecture offers higher efficiency figures compared to the conventional linear EA

  • Slew-rate and efficiency trade-off in slow envelope tracking power amplifiers

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Vizarreta Paz, Pedro Pablo
    German Microwave Conference
    p. 1-4
    DOI: 10.1515/freq-2012-0101
    Presentation's date: 2012-03-12
    Presentation of work at congresses

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    This paper presents a study on the trade-off between the envelope's slew-rate and the drain efficiency when slower envelopes are considered to dynamically supply the power amplifier (PA). This paper discusses a method to limit the slew-rate (and consequently the bandwidth) of the signal's envelope. Moreover, since the envelope tracking (ET) technique using a slower version of the original envelope introduces nonlinear distortion, slow envelope dependent predistortion has to be also incorporated in the design of ET PAs. Experimental results showed that it is possible to find a compromise between the bandwidth and slew-rate reduction (necessary to cope with the specific envelope amplifier requirements) and the amount of drain efficiency degradation suffered due to the use of a slower version of the original envelope.

  • Look-up table implementation of a slow envelope dependent digital predistorter for envelope tracking power amplifiers

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    IEEE microwave and wireless components letters
    Vol. 22, num. 2, p. 97-99
    DOI: 10.1109/LMWC.2011.2181973
    Date of publication: 2012-02-13
    Journal article

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    This letter presents a dynamic slow envelope dependent digital predistorter (SED-DPD) capable of compensating for the nonlinear distortion and memory effects that arise in envelope tracking (ET) power amplifiers (PAs) when using a slow version of the signal's envelope to dynamically supply the PA drain voltage. Moreover, a new DPD architecture based on the combination of several basic predistortion cells (BPCs) is presented to allow the FPGA implementation of the proposed SED-DPD. Finally, results showing the necessity and linearization performance of the proposed dynamic SED-DPD are provided.

  • Soluciones de procesado digital de la señal para sistemas inalambricos sostenibles y reconfigurables

     Montoro López, Gabriel; Bertran Alberti, Eduardo; Berenguer Sau, Jordi; Gelonch Bosch, Antoni; Marojevic, Vuk; Vizarreta Paz, Pedro Pablo; Gómez, Ismael; Gomez Miguelez, Ismael; Hernandez Marco, Jordi; Gilabert Pinal, Pere Lluis
    Competitive project

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    RF and accelerating structure of 12 MeV UPC race-track microtron  Open access

     Koubychine Merkulov, Youri Alexandrovich; Gonzalez, Xavier; Montoro López, Gabriel; Carrillo, David; Garcia-Tabares, Luis; Toral, Fernando; Mathot, Serge Jean; Shvedunov, V.I.
    International Particle Accelerator Conference
    p. 169-171
    Presentation of work at congresses

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    We describe the design and technical characteristics of a C-band SW accelerating structure of a 12 MeV race-track microtron, which is under construction at the Technical University of Catalonia, and its RF system with a 5712 MHz magnetron as a source. Results of cold tests of the accelerating structure, before and after the brazing, and of high-power tests of the RF system at a special stand are reported. The main features of the magnetron frequency stabilization subsystem are also outlined.

  • Power amplifier nonlinear modeling for digital predistortion

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    Date of publication: 2011-09-29
    Book chapter

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    Postprint (author’s final draft)

  • Look-up table based digital predistortion schemes and implementation

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel
    Date of publication: 2011-09-29
    Book chapter

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    Postprint (author’s final draft)

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    Incremental behavioral modeling of envelope-dependent nonlinear distortion in dynamic supply power amplifiers  Open access

     Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; Vizarreta Paz, Pedro Pablo
    Simposium Nacional de la Unión Científica Internacional de Radio
    p. 7-
    Presentation's date: 2011-09-08
    Presentation of work at congresses

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    This paper presents behavioral modeling of an envelope tracking (ET) power amplifier (PA) excited by an slewrate limited envelope. In order to relax the slew-rate requirements of current efficient envelope amplifiers (EA), we can drive the ET PA with a slower version of the signal’s envelope. However, the resulting amplified signal suffers from nonlinear distortion due to the time-variant gain effects that arise when using the slower version of the signal’s envelope. In this paper this time-variant effects are presented and characterized. A new envelope-dependent (ED) behavioral model is presented and compared with a simpler static AM-AM and AM-PM modeling. Experimental results showing the performance of the proposed ED model were obtained with an ET PA based on a GaN transistor.

  • FPGA implementation of a real-time NARMA-based digital adaptive predistorter

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Bertran Alberti, Eduardo
    IEEE transactions on circuits and systems II: express briefs
    Vol. 58, num. 7, p. 402-406
    DOI: 10.1109/TCSII.2011.2158256
    Date of publication: 2011-07
    Journal article

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  • Digital predistortion of envelope tracking amplifiers driven by slew-rate limited envelopes

     Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; Berenguer Sau, Jordi; Bertran Alberti, Eduardo
    IEEE International Microwave Symposium
    p. 1-4
    Presentation's date: 2011-06-09
    Presentation of work at congresses

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  • Digital processing compensation mechanisms for highly efficient transmitter architectures

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Vizarreta Paz, Pedro Pablo; Berenguer Sau, Jordi
    IET microwaves antennas and propagation
    Vol. 5, num. 8, p. 963-974
    DOI: 10.1049/iet-map.2010.0368
    Date of publication: 2011-06-06
    Journal article

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  • Puesta en marcha de un microtron compacto de electrones

     Duch Guillen, Maria Amor; Roure Fernandez, Francisco; Montoro López, Gabriel; Koubychine Merkulov, Youri Alexandrovich
    Competitive project

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    El transmisor sostenible  Open access

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Bertran Alberti, Eduardo; Berenguer Sau, Jordi
    Telecos.cat. Enginyers de Telecomunicació
    num. 53, p. 16-18
    Date of publication: 2011-03-01
    Journal article

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  • Slew-rate limited envelopes for driving envelope tracking amplifiers

     Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; Vizarreta Paz, Pedro Pablo; Bertran Alberti, Eduardo
    IEEE Radio & Wireless Symposium
    p. 17-20
    DOI: 10.1109/PAWR.2011.5725386
    Presentation's date: 2011-01-17
    Presentation of work at congresses

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    This paper presents a practical application of a method for generating slew-rate limited envelopes in order to drive the dynamic supply of envelope tracking (ET) power amplifiers (PAs). The proposed method results useful to generate slower versions of the transmitted signal’s envelope to cope with the slew-rate and bandwidth limitations of envelope amplifiers. Moreover, this paper shows experimental results comparing the performance of ET when exciting the drain of a PA (based in a GaN transistor) with both the envelope of the signal and the slew-rate limited version of the envelope.

  • Resource management strategies for SDR clouds

     Marojevic, Vuk; Gomez Miguelez, Ismael; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Gelonch Bosch, Antoni
    Wireless Innovation Forum Conference on Communications Technologies and Software Defined Radio
    p. 162-168
    Presentation of work at congresses

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    This paper analyzes different resource management strategies for SDR base stations implemented as SDR clouds. SDR clouds describe distributed antennas that connect to a data center for digital signal processing. The data center employs cloud computing technology, providing a virtualized computing resource pool. The service area of a single SDR cloud may be a medium sized metropolitan area with a high user density. Hence, the data center will execute thousands of SDR applications—waveforms associated to different radio cells—in parallel. Whenever a user initiates or terminates a wireless communications session, computing resources need to be allocated or deallocated in real time. We therefore propose a hierarchical resource management approach and present simulation results that demonstrate its feasibility

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    SDR in undergraduate engineering education  Open access

     Marojevic, Vuk; Gomez Miguelez, Ismael; Olmos Bonafé, Juan José; Montoro López, Gabriel; Gelonch Bosch, Antoni
    Wireless Innovation Forum Conference on Communications Technologies and Software Defined Radio
    p. 1-6
    Presentation's date: 2010-11-30
    Presentation of work at congresses

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    Implementation issues in FPGA-controlled polar transmitters  Open access

     Gilabert Pinal, Pere Lluis; Cabria, Lorena; García García, José Ángel; Montoro López, Gabriel; Bertran Alberti, Eduardo
    European Microwave Week
    p. 711-714
    Presentation's date: 2010-09-30
    Presentation of work at congresses

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    Arquitecturas de transmisión inalámbrica de alta eficiencia  Open access

     García García, José Ángel; de Mingo, Jesús; Montoro López, Gabriel; Cabria, Lorena; Marante, Reinel; García, Paloma; Sánchez, César; Bertran Alberti, Eduardo; Gilabert Pinal, Pere Lluis
    Simposium Nacional de la Unión Científica Internacional de Radio
    p. 1-4
    Presentation's date: 2010-09-15
    Presentation of work at congresses

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    Implementación de un transmisor LINC en un procesador FPGA  Open access

     Vizarreta Paz, Pedro Pablo; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Berenguer Sau, Jordi
    Simposium Nacional de la Unión Científica Internacional de Radio
    p. 1-4
    Presentation's date: 2010-09-15
    Presentation of work at congresses

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    On PAPR for combined modulation and access techniques in configurable radio  Open access

     Bertran Alberti, Eduardo; Porta, Oriol; Montoro López, Gabriel; Delgado Penin, Jose A.
    IEEE International Microwave Workshop Series on RF Front-Ends for Software Defined and Cognitive Radio Solutions
    p. 37-40
    Presentation's date: 2010-02-23
    Presentation of work at congresses

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  • Gastos de Optimización de los Amplificadores de los BPM Instalados en la TBL de CTF3 i Financiación de Actividades de Colab. con CER

     Gilabert Pinal, Pere Lluis; Koubychine Merkulov, Youri Alexandrovich; Montoro López, Gabriel
    Competitive project

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    A method for real-time generation of slew-rate limited envelopes in envelope tracking transmitters  Open access

     Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; Bertran Alberti, Eduardo; Berenguer Sau, Jordi
    IEEE International Microwave Workshop Series on RF Front-Ends for Software Defined and Cognitive Radio Solutions
    p. 1-4
    Presentation's date: 2010-02-22
    Presentation of work at congresses

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    FPGA-based set-up for RF power amplifier dynamic Supply with real-time digital adaptive predistortion  Open access

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Bertran Alberti, Eduardo; García García, José Ángel
    IEEE Radio & Wireless Symposium
    p. 1-4
    Presentation's date: 2010-01-12
    Presentation of work at congresses

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    Comissioning of the decelerator test beam line in CTF3  Open access

     Adli, E; Döbert, Steffan; Lillestol, R; Olvegaard, M; Syratchev, I; Carrillo, David; Toral, Fernando; Faus-Golfe, Angeles; García-Garrigos, JJ; Koubychine Merkulov, Youri Alexandrovich; Montoro López, Gabriel
    Linear Accelerator Conference
    p. 85-87
    Presentation of work at congresses

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    The CLIC Test Facility (CTF3) at CERN was constructed by the CTF3 collaboration to study the feasibility of the concepts for a compact linear collider. The test beam line (TBL) recently added to the CTF3 machine was designed to study the CLIC decelerator beam dynamics and 12 GHz power production. The beam line consists of a FODO lattice with high precision BPM’s and quadrupoles on movers for precise beam alignment. A total of 16 Power Extraction and Transfer Structures (PETS) will be installed in between the quadrupoles to extract 12 GHz power from the drive beam provided by the CTF3 machine. The CTF3 drive beam with a bunchtrain length of 140 ns, 12 GHz bunch repetition frequency and an average current over the train of up to 28 A will be injected into the test beam line. Each PETS structure will produce 135 MW of 12 GHz power at nominal current. The beam will have lost more than 50 % of its initial energy of 150 MeV at the end of the beam line and will contain particles with energies between 65 MeV and 150 MeV. The beam line is completely installed and the PETS structures will be successively added until the end of 2011. The paper will describe the first results obtained during commissioning of the beam line and the first PETS prototype.

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    On passive bias networks for drain-modulated power amplifiers  Open access

     Bertran Alberti, Eduardo; García García, José Ángel; Montoro López, Gabriel; Gilabert Pinal, Pere Lluis; Berenguer Sau, Jordi
    International Symposium on Microwave and Optical Technology
    p. 34-36
    Presentation's date: 2009-12-16
    Presentation of work at congresses

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  • Microtró: Accelerador de partícules

     Berenguer Sau, Jordi; Montoro López, Gabriel; Koubychine Merkulov, Youri Alexandrovich
    Competitive project

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    Técnicas Emergentes de Mejora del Compromiso Eficiencia-Linealidad en Transmisores de Radiofrecuencia  Open access

     García García, José Ángel; de Mingo, Jesús; Montoro López, Gabriel; Cabria, Lorena; Marante, Reinel; García, Paloma; Sánchez, Cesar; Bertran Alberti, Eduardo; Gilabert Pinal, Pere Lluis
    Simposium Nacional de la Unión Científica Internacional de Radio
    Presentation's date: 2009-09-17
    Presentation of work at congresses

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    Postprint (author’s final draft)

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    Análisis comparativo de técnicas de reducción de PAPR en señales OFDM  Open access

     Lopez Caro, Alberto; Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Bertran Alberti, Eduardo; Jove Casals, Jose M.
    Simposium Nacional de la Unión Científica Internacional de Radio
    Presentation's date: 2009-09-17
    Presentation of work at congresses

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    Postprint (author’s final draft)

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    An efficient combination of digital predistortion and OFDM clipping for power amplifiers  Open access

     Gilabert Pinal, Pere Lluis; Gadringer, ME; Montoro López, Gabriel; Mayer, ML; Silveira, DD; Bertran Alberti, Eduardo; Magerl, G
    International journal of RF and microwave computer-aided engineering
    Vol. 19, num. 5, p. 583-591
    Date of publication: 2009-09
    Journal article

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    This paper derives a general analytical expression of the feasibility condition for the uplink of a CDMA mobile communications system in a general scenario where the users in the system belong to an arbitrary number of service classes and the coverage deployment includes the presence of repeaters. An explicit expression of the admission region is derived and the dependencies on the parameter values are shown. An example is presented in order to illustrate the application of the proposed methodology in a real case.

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    Improvements and analysis of nonlinear parallel behavioral models  Open access

     Silveira, DD; Gilabert Pinal, Pere Lluis; Lavrador, PM; Pedro, JC; Gadringer, M; Montoro López, Gabriel; Bertran Alberti, Eduardo; Magerl, G
    International journal of RF and microwave computer-aided engineering
    Vol. 19, num. 5, p. 615-626
    DOI: 10.1002/mmce
    Date of publication: 2009-09
    Journal article

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    FPGA implementation of an LMS-based real-time adaptive predistorter for power amplifiers  Open access

     Gilabert Pinal, Pere Lluis; Bertran Alberti, Eduardo; Montoro López, Gabriel; Berenguer Sau, Jordi
    North -East Workshop on Circuits and Systems/TAISA
    p. 268-271
    Presentation's date: 2009-06-28
    Presentation of work at congresses

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  • Nonlinear Auto Regressive Moving Average Models

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Bertran Alberti, Eduardo
    Date of publication: 2009-01-31
    Book chapter

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    A full FPGA-based implementation of an adaptive digital predistorter  Open access

     Gilabert Pinal, Pere Lluis; Montoro López, Gabriel; Bertran Alberti, Eduardo
    IEEE Topical Symposium on Power Amplifiers for Wireless Communications
    p. 1-2
    Presentation's date: 2009-01-19
    Presentation of work at congresses

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  • TECNICAS DIGITALES AVANZADAS PARA TECNOLOGIAS EMERGENTES EN TRASMISORES INALAMBRICOS

     Hernandez Marco, Jordi; Bertran Alberti, Eduardo; Delgado Penin, Jose A.; Gilabert Pinal, Pere Lluis; Berenguer Sau, Jordi; Montoro López, Gabriel
    Competitive project

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