Gps-based High-stability Frequency Source And Realization

The frequency stability of frequency source system is a very important target aim for communication system. Long-term stability and short-term stability of frequency source system are defined by the sampling interval in testing process. In practical application frequency source system needs to have both excellent long-term stability and short-term stability. This dissertation aims to realize such a highly-stable frequency source system.Because the frequency signals received from GPS satellites have good long-term stability and the frequency signals of local oscillator have good short-term stability, the dissertation use frequency synthesis to lock frequency signals of local oscillator to GPS frequency signals to achieve a highly-stable frequency source system.This dissertation analyses the GPS frequency calibration principle. Based on this principle, the dissertation designs GPS receiver and frequency synthesis. GPS receiver uses U-BLOX LEA4H as the core of the receiver circuit. The impedance matching of transmission line is very important for RF design and essential for the stabilization of receiver system, so this dissertation analyses impedance matching of transmission deeply. Frequency synthesis uses PLL to synthesize oscillator frequency and GPS frequency signals. Phase detector, loop filter, VCO and frequency divider are designed in this dissertation. The improvement of some circuit links and system comprehensive performance is also discussed in the dissertation. Finally the dissertation gives the system experiment result. Experiment result shows that the long-term stability and short-term stability of oscillator frequency are improved through the method described in this dissertation.