Broadband Frequency Agile Frequency Synthesizer Of Research And Design

Frequency synthesizer is the key component in electronic systems. By the great development of modern electronic communication, Radar, electronic detector and electronic countermeasures technology, higher requirement is needed by the system. According to different application fields, the point system emphasizes is also different. Frequency's switching time, which directly affects the hopping speed of interferential system as well as Radar's frequency agility, is being paid more and more attention.This paper mainly analyzed the frequency synthesizer's agile character. This paper firstly summarized the development of frequency synthesis technology, then analyzed the basic working principle of various frequency synthesis theories, including analog direct frequency synthesis, digital direct frequency synthesis and PLL synthesis, especially described how to achieve fast-switching by these frequency synthesis, and discussed their advantage, disadvantage and the application range separately. What is more, the methods to measure the switching time were also discussed. After considering the difficulty and the universality for application, paper made deep research on PLL's capture time and supplementary pull-in method, especially VCO pre-tuning method. Then, detail discusses were given on.Finally, on the basis of above analysis and research, by comparing various design methods, a L band agile frequency synthesizer with 256MHz bandwidth and 1MHz resolution was designed, whose switching time was within 4 us. However, the spur performance is to be improved.