Search for dissertations about: "nonlinear distortion"

Showing result 16 - 20 of 66 swedish dissertations containing the words nonlinear distortion.

  2. 16. Digital Predistortion for the Linearization of Power Amplifiers

    Author : Jessica Chani Cahuana; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; behavioral model; Volterra series; nonlinear; digital predistortion; Doherty power amplifier; power amplifier; efficiency;

    Abstract : High efficiency and linearity are indispensable requirements of power amplifiers. Unfortunately they are difficult to obtain simultaneously, since high efficiency PAs are nonlinear and linear PAs may have low efficiency. READ MORE

  4. 17. A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT)

    Author : Behrooz Oskooi; Laust Börsting Pedersen; Thorkild Mack Rasmussen; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geophysics; Airborne; azimuthal anisotropy; CSTMT; distortion; EM; geothermal; Hengill; mineralization; MT; peaker; resolution; RMT; tipper; tensor VLF; VLF; Geofysik; Geophysics; Geofysik;

    Abstract : The resolution power of single Very Low Frequency (VLF) data and multi-frequency Radiomagnetotelluric (RMT) data in delineating conductive structures typical for the sedimentary cover and crystalline basement in Scandinavia is studied with a view to future developments of the technique to increasing the frequency range into the LW radio band. Airborne and ground VLF data are interpreted and correlated with RMT measurements made on the ground to better understand the resolution power of VLF data. READ MORE

  5. 18. Modeling Approaches for Active Antenna Transmitters

    Author : Parastoo Taghikhani; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; thermal model.; MIMO; power amplifier; Active antenna transmitter; hybrid beamforming; electrothermal; active subarray antenna; nonlinear distortion;

    Abstract : The rapid growth of data traffic in mobile communications has attracted interest to Multiple-Input-Multiple-Output (MIMO) communication systems at millimeter-wave (mmWave) frequencies. MIMO systems exploit active antenna arrays transmitter configurations to obtain higher energy efficiency and beamforming flexibility. READ MORE

  6. 19. Modeling and Compensation of Nonlinear Distortion in Multi-Antenna RF Transmitters

    Author : Katharina Hausmair; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multi-antenna transmitter; behavioral modeling; over-the-air characterization; digital predistortion; antenna crosstalk; linearization; power amplifier;

    Abstract : Multi-antenna systems are utilized as a way to increase spectral efficiency in wireless communications. In a transmitter, the use of several parallel transmit paths and antennas increases system complexity and cost. Cost-efficient solutions, which employ active antenna arrays and avoid expensive isolators, are therefore preferred. READ MORE

  7. 20. On Nonlinear Acoustics in Contrast Echocardiography

    Author : Marcus Ressner; Birgitta Janerot-Sjöberg; Per Ask; Tomas Jansson; Hans Torp; Linköpings universitet; []
    Keywords : TECHNOLOGY; TEKNIKVETENSKAP;

    Abstract : Ultrasound is one of the most commonly used noninvasive medical imaging techniques. Ultrasound contrast agents (UCA), consisting of encapsulated gas-filled microbubbles, have shown to increase the diagnostic precision in selected low echogenic patients. READ MORE