The Design Of GPS Clock Synchronization System In Distributed Text System

Clock synchronization generates and provides time and frequency standard in distributed test, which makes the whole distributed test system work at the same time-scale, and is the foundation of information exchange and collaborative work. The clock synchronization system with high-precision is vital for high-frequency transient signal measurement and network test. Because the global positioning system (GPS) has the signal covering all over the world in all weather and the high-precision atomic clock which can be used as time-frequency standard, and is low-cost and easy to realize high-precision synchronization, it is gradually used in distributed test.According to the engineering demands of"local-area positioning system based on distributed base station", this paper mainly researches clock synchronization system of distributed base station based on the GPS. According to the principle of GPS, based on the GPS second-pulse with long-term stability and local crystal with short-term high-stability, this paper designs a set of synchronization time measuring system with crystal clock pulse resolution. This system consists of SCM ATmega16L, CPLD EPM570, GPS module M12MT and peripheral circuit, mainly completing GPS clock information receiving, 20ns crystals pulse generation, synchronous trigger pulse detection, time record and time calibration of test data. Based on the hardware and function above, this paper designs the system management and control software using C and VHDL.Experiment result shows that this system has advantages of high time synchronization precision, good stability and low cost etc, meets the demands of local positioning system of distributed base stations, and also can be applied to the wireless sensor network test and clock synchronization of radio telemetry system.