Research On Microwave Frequency Synthesizer Ranging From 10MHz To 4GHz With Low Phase Noise

With the development of modern communications, radar and electronic counter measures and several relative fields, frequency synthesizer exerted a great influence on the whole electrical system and got to be foundation of the modern electrical measurement devices. Since the performances of the whole system greatly relied on the characteristics of frequency synthesizer, it was required that the frequency synthesizer must have excellent characteristics. The characteristics which influenced the systematic performances included phase noise, switching time, frequency resolution, frequency range and power level and etc. Frequency synthesize technique originated in 1930s and had a history of more than seventy years. Four kinds of method to realize frequency synthesize gradually formed as the improvement of interrelated new techniques, they were direct frequency synthesize, indirect frequency synthesize, direct digital frequency synthesize and mixed frequency synthesize. Among these, techniques of indirect frequency synthesize and direct digital frequency synthesize play an important role in fields of nowaday frequency synthesize for their extraordinary advantages.Based on the historical background of frequency synthesizers, the operation principles of respective parts of indirect frequency synthesizers are introduced in this thesis. Meanwhile, the phase noise model of phase-locked loop and its influence parameters are analyzed; and the direct digital frequency synthesize technique is also been depicted. After these, the thesis brings up a feasible implementation draft according to the requirements, carries out the theoretical calculation and experimental simulation, and finally realizes some expected functions of the design.