Design ofMulti-carrier Digital Frequency Synthesizer forCoast-ship Multi-static Ground
ChenBaixiao andZhangShouhong LiFenglin · 2006
To designa digital frequency synthesizer of multi-carrier frequencies fortheCoast-ship Multi-static GroundWaveOver-the-horizon (OTH)Radar, ananalysis of theapproach hasbeenmadebyusingmultiple DDS chips AD9854.Theconstitution oftheradarisintroduced briefly. The synthesizer generates multiple signals of Linear FrequencyModulatedInterrupted Continuous Wave (LFMICW)whichshould havedifferent carrier frequencies aswellascontrollable initial phases andwill betransmitted simultaneously. Aneffective methodforgenerating LFMICW byadvanced DDS technology isproposed inthepaper. The designs oftheFPGAcontrol logic andtheperipheral circuits arepresented aswell. Thesynthesizer hasbeenimplemented intheexperimental radarsystem. Theexperimental results indicate thatthephasenoise ofthefrequency synthesizer is -92.6dBc@lHz, whichhasmetthestability demandsforlong termcoherent integration inhighfrequency groundwave radar.