A Study Of Microwave Wideband Frequence Synthesis Technology

The frequency synthesizer converts one standard frequency to thousands of frequencies with the same high stability and veracity as the standard frequency. It is applied to many fields such as communication , navigation , radar and EW, it is thought as the"heart"of the electronic instruments , it is also important to receivers . With the need of the military development , the frequency band of signal collection is extending . It is necessary to study the microwave frequency synthesizer with wide_band and fine_resolution. The chief work in this article is to study the C~X band frequency synthesizer satisfying the need of wide_band turning recivers . This artical is consisted of five chapters.In chapter 1 , it mainly describes the developing survey in the frequency synthesizer fields and some familiar forms of the frequency synthesizer , which features are analysed respectively. In chapter 2 , it discusses the development and working principles of the Phase Lock Loop's technique , and it introduces the basic characteristics of the primary components of PLL. Then by the PLL's linear analysis with its equation, the author reaches a conclusion of some important parameters and characteristics of PLL. At last, by building phase noise model of PLL, the author analyses the influence of the total output noise upon each of the PLL's components, and brings forward the question"how to select the optimistic parameters of PLL".In chapter 3 , it discusses the Digital Direct Synthesizer's (DDS) working principles and characteristics, and then a detailed DDS's spectrum analysis is given. At the end of this chapter, some measures to improve the DDS's spectrum character are brought forward .In chapter 4 , after analyzing the general scheme, PLL and DDS are adopted to get the 900MHz~1500MHz fine_resolution synthesizer , then the frequency band is extended to the C~X band through Direct Analogy Synthesizer. The key features of the frequency synthesizer are described and it's key components are designed. The simulation and the testing results of the wide_band amplifier and the high multiplier are explained . At the same time, 900MHz~1500MHz synthesizer is finished . Finally, the testing results of the whole microwave frequency synthesizer are showed .In chapter 5 , it simply describes the work and pictures the developing direction of frequency synthesizer .The author thinks that the technique of frequency synthesizer will develop towards wide bandwidth, miniaturization, modularization, intelligentizing multiple function, etc.