Section Covers 3 M - 5 Ghz Transceiver Frequency Source Design

With the rapid development of modern electronic technology, the demand of research on frequency synthesizers with excellent performance simultaneously, such as frequency range, frequency stability, frequency purity, hopping speed and frequency resolution, etc, has been urgently raised.In this dissertation, the basic theory of frequency of wide frequency coverage, low phase noise, low spurious, hopping is compared and discussed. They are all on the basis of today’s frequency synthesis theoretical and technical theory.Frequency synthesis technology’s development and status quo are introduced firstly in this dissertation and then on the basis of it, PLL and DDS’s basic structure and working principle are explained, the main source of phase noise and spurious are summarized.Secondly, on the basis of the above theory, several frequency synthesis methods of DSS mixed PLL are compared on performance, according to the request made by using, the method of DDS directly drive the PLL is proposed to achieve the local oscillator signal of wide coverage, low phase noise and low spurious. And through theoretical analysis and software simulation, the feasibility of this scheme has been verified.Then, the author describes the core chips of AD9910and ADF430’s selection and introduce their characteristics, circuit design of each module, the PCB drawing and cavity assembly. Finally, the tests show that the results of relevant indicators meet the technical requirements specified in the agreement. For this project, the emergence of some phenomena and problems are analyzed in the test, and gives the corresponding solution, and summarizes some of the inadequacies of this design, make a certain reference of the wide coverage and low phase noise frequency synthesizer design similarly.