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Design of High Integrated Low Phase Noise Phase-Locked Loop Frequency Synthesizer System

A design method of a local oscillator operated on C band was proposed in this paper for the high stability, high precision and light weight of the Unmanned Aerial Vehicle (UAV) data link radio frequency transmitting unit. Based on high integrated broadband phase-locked loop chip (HMC834), the system was designed by adopting the internal programming models for the fractional-N control, and the high phase noise and small frequency step of the output could be realized. The simulation and testing method were combined to optimize and select the parameters of the filter circuit, and realize high precision phase-locked frequency synthesis output in the hardware design process. The theoretical analysis and engineering prototype measurement results showed that the local oscillator had stable output frequency, accurate frequency step, high spurious suppression and low phase noise, and met the design requirements. The proposed design idea and research method have theoretical guiding sense for engineering practice.