Sökning: "quadrature domain"

Visar resultat 6 - 10 av 16 avhandlingar innehållade orden quadrature domain.

  1. 6. High Order Cut Finite Element Methods for Wave Equations

    Författare :Simon Sticko; Gunilla Kreiss; Mats G. Larson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cut finite element; Wave equation; Immersed; Fictitious domain; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : This thesis considers wave propagation problems solved using finite element methods where a boundary or interface of the domain is not aligned with the computational mesh. Such methods are usually referred to as cut or immersed methods. LÄS MER

  3. 7. DSP based Chromatic Dispersion Equalization and Carrier Phase Estimation in High Speed Coherent Optical Transmission Systems

    Författare :Tianhua Xu; Sergei Popov; Gunnar Jacobsen; Jie Li; Seb Savory; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; coherent detection; chromatic dispersion; carrier phase estimation; quadrature phase shift keying; SRA - ICT; SRA - Informations- och kommunikationsteknik;

    Sammanfattning : Coherent detection employing multilevel modulation formats has become one of the most promising technologies for next generation high speed transmission systems due to the high power and spectral efficiencies. Using the powerful digital signal processing (DSP), coherent optical receivers allow the significant equalization of chromatic dispersion (CD), polarization mode dispersion (PMD), phase noise (PN) and nonlinear effects in the electrical domain. LÄS MER

  4. 8. Frequency Noise in Coherent Optical Systems: Impact and Mitigation Methods

    Författare :Aditya Kakkar; Richard Schatz; Sergei Popov; Gunnar Jacobsen; Xiaodan Pang; Oskars Ozolins; Magnus Karlsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Equalization enhanced phase noise; frequency noise; coherent optical communications; carrier phase recovery; carrier phase estimation; circular quadrature amplitude modulation; EEPN; CmQAM; blind phase search; phase noise;

    Sammanfattning : The increase in capacity demand along with the advancement in digital signal processing (DSP) have recently revived the interest in coherent optical communications and led to its commercialization. However, design and development of robust DSP algorithms for example for carrier phase recovery (CPR) becomes complex as we opt for high order modulation formats such as 16QAM and beyond. LÄS MER

  5. 9. Free Boundary Problems of Obstacle Type, a Numerical and Theoretical Study

    Författare :Mahmoudreza Bazarganzadeh; Henrik Shahgholian; John King; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Partial differential equations; Numerical analysis; Free boundary problems; Mathematics; Matematik;

    Sammanfattning : This thesis consists of five papers and it mainly addresses the theory and schemes to approximate the quadrature domains, QDs. The first deals with the uniqueness and some qualitative properties of the two QDs. The concept of two phase QDs, is more complicated than its one counterpart and consequently introduces significant and interesting open. LÄS MER

  7. 10. Digital Dispersion Equalization and Carrier Phase Estimation in 112-Gbit/s Coherent Optical Fiber Transmission System

    Författare :Tianhua Xu; Sergei Popov; Gunnar Jacobsen; Jie Li; Magnus Karlsson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Coherent transmission; chromatic dispersion; carrier phase estimation; digital signal processing; Optics; Optik; Photonics; Fotonik; SRA - ICT; SRA - Informations- och kommunikationsteknik;

    Sammanfattning : Coherent detection employing multilevel modulation format has become one of the most promising technologies for next generation high speed transmission system due to the high power and spectral efficiencies. With the powerful digital signal processing (DSP), coherent optical receivers allow the significant equalization of chromatic dispersion (CD), polarization mode dispersion (PMD), phase noise (PN) and nonlinear effects in the electrical domain. LÄS MER