Today,as the electronic technology is developing fantasticly fast,the request for higher performance of synthesizers is put forward,especially the low phase noise performsnce.As the PLL is the main force of modern synthesizer,do a forwad research in technology of low phase noise design is very necessary.For this reason,the paper is mainly focus on the theory and technology of low phase noise PLL design.This paper mainly introduce the teconology of design modern microwave hopping frequency PLL synthesizer with low phase noise.On the foundation of analysis of phase noise performance of PLL circuit,I made some reasearch in system shcemes and methods for low phase noise design of microwave hopping frequency PLL.Some innovative ideas of low phase noise design about PLL is presented in this paper.In the begginning of the paper,I made some comparasion ammong modern frequency synthesizer,In succession,I Analysis phase noise contribution made by the P the make-up parts of PLL system including loop filter of PLL.As result,I have gotten the algorithm for accurate predication phase noise in PLL synthesizer.Then I made some details on Fraction-N PLL. At last, some low phase noise PLL designs are to be presented by me to verify the theroies of low phase noise design .All in a word,this article provide some meaningfull instruction for low phase noise hopping frequency PLL design. |