Sökning: "Quadrature hybrid"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Quadrature hybrid.

  1. 1. Periodic structures and lumped elements in microwave passives

    Författare :Dan Kuylenstierna; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Passive elements; Lumped elements; Photonic bandgap; Metamaterial; MMIC; Electromagnetic bandgap; Ferroelectric; Quadrature hybrid; Quadrature power splitter; Balun; Periodic structures;

    Sammanfattning : The ambition of this work is the incorporation of ferroelectric varactors as tuneable elements in Si integrated circuits (ICs). This thesis presents partialfulfillments of the work. LÄS MER

  3. 2. On Performance Analysis of Retransmission Schemes with Fading Channels

    Författare :Peter Larsson; Lars Kildehøj Rasmussen; Mikael Skoglund; Leszek Szczecinsky; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Automatic repeat request; ARQ; hybrid-arq; retransmission schemes; Telecommunication; Telekommunikation;

    Sammanfattning : Future wireless communication systems and services bring increased performance demands, with respect to data-rate(s), reliable communication, (stochastic) real-time guarantees, and more. In this context, not only new communication schemes are needed, but also more capable performance analysis methods are essential. LÄS MER

  4. 3. Modulation Optimization for Noncoherent Optical Systems

    Författare :Johnny Karout; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct detection; noncoherent communications; lattice codes; mutual information; fiber-optical communications; intensity modula- tion; sphere packing.; infrared communications; free-space optical communications;

    Sammanfattning : There has been a significant improvement in high-speed electronics and optical components over the past few years, and this is one of the key enabling factors for high data rate transmission. Moreover, multi- level modulation formats, which encode information onto the carrier’s amplitude and phase, are necessary to increase the spectral efficiency of communication systems. LÄS MER

  5. 4. Computational Techniques for Coupled Flow-Transport Problems

    Författare :Martin Kronbichler; Gunilla Kreiss; Jean-Luc Guermond; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Finite element method; saddle point systems; two-phase flow; level set method; phase field method; stabilization; contact line dynamics; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : This thesis presents numerical techniques for solving problems of incompressible flow coupled to scalar transport equations using finite element discretizations in space. The two applications considered in this thesis are multi-phase flow, modeled by level set or phase field methods, and planetary mantle convection based on the Boussinesq approximation. LÄS MER

  7. 5. On Bit-interleaved Coded Modulation with QAM Constellations

    Författare :Alex Alvarado; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Bit-interleaved coded modulation (BICM) is a flexible modulation/coding scheme which allows the designer to choose a modulation constellation independently of the coding rate. This is because the output of the channel encoder and the input to the modulator are separated by a bit-level interleaver. LÄS MER