Chendu Railway Port Of Project Risk Management Research

With the rapid development of modern electronic technology, the demand of research on frequency synthesizers with excellent performance simutaneously, such as frequency stability, frequency purity, hopping speed, frequency coverage etc, has been urgently raised. The properties of microwave and millimeter-wave signals such as short wave length and wide bandwidth are useful for the military guidance and electronic countermeasures, and therefore have attracted increasing concentrations.In this thesis, the basic theory of frequency synthesis is discussed. Then the novel and improved algorithms and structures of frequency synthesis are proposed:1. A novel agile frequency synthesis algorithm to achieve wide frequency coverage and low phase noise is proposed. By adjusting the gain of phase frequency detector(PFD) of phase locked loop(PLL) to compensate the nonlinear behavior of voltage controlled oscillator and keep the loop bandwidth of PLL approximately constant, both of agilty and frequency purity of synthesizer over the output bandwidth can be ensured.2. An improved multiple-tuned PLL driven by DDFS structure of frequency synthesizer is proposed. By tuning multiple factors in the frequency syntheizer structure, the flexibility of frequency configuration can be provided to achieve high performance.3. A design approach of microwave and millimeter-wave transceiver is proposed. By optimizing the frequency configuration of up-conversion and down-conversion structures, the advantages of DDFS, PLL and FPGA can be fully taken to achieve high performance on frequency purity and swithing time.4. A novel truncation spurious free DDFS structure and algorithm is proposed. By introducing a comparator and an adder into the traditional DDFS architecture, the sine lookup table can be compressed without significant hardware change in the design to eliminate the truncation spurs without increasing the size of the lookup table.