Sökning: "UTC"

Visar resultat 1 - 5 av 12 avhandlingar innehållade ordet UTC.

  1. 1. Real-Time Time Metrology Using Space Geodetic Methods

    Författare :Carsten Rieck; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; VLBI; Time metrology; UTC; TAI; time link combination; carrier phase; time transfer; real-time filtering; GNSS;

    Sammanfattning : Two main objectives in time and frequency metrology are the realization of the SI unit of time, and the construction and dissemination of atomic time scales based on the SI second. This thesis is mainly concerned with the latter of the two and has investigated the characteristics of space geodetic time and frequency comparison methods. LÄS MER

  3. 2. Frequency Transfer Techniques and Applications in Fiber Optic Communication Systems

    Författare :Sven-Christian Ebenhag; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; synchronous digital hierarchy SDH ; UTC; synchronization; Time transfer; optical fiber; optical fiber network; GPS carrier phase; global positioning system GPS ; synchronous optical networking SONET ;

    Sammanfattning : Modern society is dependent on communications and the developments of these increases constantly through a seemingly endless demand for communication services and thereby synchronization and time. This is confirmed by a vast range of research on communications, irrespective of technology and protocol. LÄS MER

  4. 3. Simulation studies of new observing concepts for geodetic Very Long Baseline Interferometry

    Författare :Grzegorz Klopotek; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Very Long Baseline Interferometry; space geodesy; Monte Carlo simulations; VGOS; c5 ; Moon; UT1-UTC;

    Sammanfattning : Very Long Baseline Interferometry (VLBI) is a space-geodetic technique in which observations are carried out simultaneously by radio telescopes separated by hundreds or thousands of kilometers. The time difference of signal reception between the telescopes is the basic observable used in geodetic VLBI. LÄS MER

  5. 4. Photonic terahertz-wave generation, radiation and quasioptical integration

    Författare :Biddut Kumar Banik; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor device modelling; semiconductor diodes; III-V semiconductors; Catadioptric lens; imaging; dipole antennas; slot antennas; lens antennas; semiconductor heterojunctions; dielectric loaded antennas; optical mixers; photomixers; near-field imaging; computer aided engineering; indium compounds; millimetre wave imaging; near-field optics; submillimeter wave generation; photodiodes; terahertz sources; millimetre wave generation; submillimetre wave integrated circuits; microwave imaging; uni-travelling-carrier photodiodes;

    Sammanfattning : This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. LÄS MER

  7. 5. Photonic THz Generation and Quasioptical Integration for Imaging Applications

    Författare :Biddut Kumar Banik; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nondestructive evaluation; semiconductor device modelling; uni-travelling-carrier photodiodes; millimetre wave and submillimetre wave generation; III-V semiconductors; photomixers; terahertz sources.; catadioptric lens; microwave imaging; dielectric loaded antennas; terahertz imaging; lens antennas; millimetre wave and submillimetre wave imaging;

    Sammanfattning : This thesis deals with the analysis and optimisation of the uni-travelling-carrier photodiode (UTC-PD) for continuous-wave generation in terahertz (THz) frequencyrange. Photonic THz generation using UTC-PDs is extremely promising as it offers wide tunability, adequate output power and room temperature operation. LÄS MER