C-band Frequency Synthesizer Developed

The fantastic development of the electronic technology is bringing forward higher request for frequency synthesizer.All frequency synthesizers with low phase noise ,highly pure spectrum and fast frequency jump speed have dominating development direction of the frequency synthesis technology . Based on this ,the paper presents "the frequency synthesizer in the C band".The content of this paper is as follow:DDS circuit module ,PLL circuit module ,microcompute control module . Firstly,based on mathematical analysis ,the paper gives an exact spectral expression of DDS due to the phase truncation and amplitude quantization. Secondly,the operation principle of microwave PLL is discussed and we emphasize the analyses of phase noise and spur ,giving formules for them.Thirdly,we discovery some special difficulty in implementing the DDS hybrid PLL system. Lastly,the paper presents the design methods of the frequency synthesizer ,and it is testified in the experiment .The main contributions and creative points of this paper are as follow:1．It gives an exact spectral expression of DDS due to the phase truncation and amplitude quantization based on mathematical analysis.It proposes a method that can design some important characters.3．It creatively focuses on the operation principle of DDS hybrid PLL system and gives some qualitative conclusions. This paper is partially supported by institute 10 of CETC.The research has been used in produce and fulfills the requirements.