Speaker
Jaromir Zajac
(Institute of Plasma Physics AS CR)
Description
The microwave reflectometry system on COMPASS tokamak uses the frequency modulated continuous wave (FM-CW) in K and Ka bands. The fast swept synthesizer together with the simple homodyne detection provides the complex beat frequency spectrum for the density profile reconstruction. The homodyne detection scheme limits the other applications like the Doppler reflectometry, therefore the sheme is rebuilt to the heterodyne system. The suitable way for the fast sweeping source is the implementation of the single sideband modulator (SSBM). Lack of suitable SSBMs on the market leads us to using of an I/Q modulator, which is modulated by the quadrature-phase signals. This contribution refers in detail to this upgrade, achieved results are shown too. With respect to the system parameters and availability of components, aspects like the choice of the modulating frequency, beat frequency, I/Q detector and others are clarified.
Co-authors
Antonio Silva
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal)
Frantisek Zacek
(Institute of Plasma Physics AS CR, v.v.i., Association EURATOM/IPP.CR, Prague, Czech Republic)
Jaromir Zajac
(Institute of Plasma Physics AS CR, v.v.i., Association EURATOM/IPP.CR, Prague, Czech Republic)
Mykyta Varavin
(Institute of Plasma Physics AS CR, v.v.i., Association EURATOM/IPP.CR, Prague, Czech Republic)
Ondrej Bogar
(Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Bratislava, Slovakia)
Sulkhan Nanobashvili
(Andronikashvili Institute of Physics, Tamarashvili St. 6, 0177 Tbilisi, Georgia)
