L-band Phase-locked Loop Fast Frequency Hopping Method

Frequency synthesizer in modern electronic technology has become the heart of the electronic system, which is the key property of electronic systems technology. With the development of communications, digital TV, Satellites, aerospace, radar and information technology, frequency synthesizer was made more and more demands. Frequency Synthesizer for the fast-lock technology is becoming a hot topic.This paper mainly introduces phase-locked loop and the charge pump switching technology, with which L-band low phase noise hopping frequency synthesizer come true. With the foundation of analysis of phase noise and spur performance of PLL circuit, some research was done in system schemes and methods for fast-locking design of hopping frequency PLL. Some innovative ideas of fast-locking design about PLL are presented in this paper.In this paper, at first, the developing history of the frequency synthesis technology is reviewed. And PLL frequency synthesis basic technology is introduced. Following, deduce the phase noise and spurs of calculating model and give the third loop filter of design method to improve the performance of PLL frequency source. Finally, the scheme of this subject, the functional realization of each module, some questions which must be paid much attention in the system design.At last, an L-band fast-locking PLL designs are to be presented to verify the theories of fast-locking design. Above all, this paper provides some meaningful research for fast-locking hopping frequency PLL design.