Design And Application Of Multi-carrier Digital Frequency Synthesizer With High Stability

The design requirement and design method are analyzed for some radar. With multiple Direct Digital Frequency Synthesizer chips and high-stable clock source, the Multi-carrier Digital Frequency Synthesizer with High Stability is designed. The Linear Frequency Modulated Interrupt Continuous Wave is designed and generated by the frequency synthesizer, whose frequency, initial phase and relational modulated parameters can be controlled conveniently. The software design, hardware design and performance test of the digital frequency synthesizer are completed as well. The digital frequency synthesizer has been applied directly to the experimental radar system. For the widely applications of the Frequency Synthesizers with High Stability (FS-HS) in the transmitter and receiver systems, the low close-in-carrier signal model of FS-HS is theorized from the fundamental of phase noise. An approach which is based on the intermediate frequency quadrature sampling technique for analyzing the phase-noise of FS-HS is presented. By compensating the first-order and second-order frequency deviation of FS-HS, the approach figures out the problem that the conventional methods can't measure FS-HS. The real data analysis results are presented according to the frequency synthesizer of some radar. At last, the initial phase demodulation method of the multi-carrier frequency synthesizer is studied according to the initial phase demodulation problem in multiple carriers. The error of initial phase demodulation of the multi-carrier frequency synthesizer is analyzed, and the real data processing results are presented as well.