Time synchronization method based on time interval measurement

In order to solve the demand of time synchronization with GPS satellite clock, a combination of high-precision time interval measurement technology and crystal taming technology is used to realize the taming control of local clock source by using standard 1PPS signal to complete the time synchronization with GPS satellite clock. The interpolation of the delay unit is completed by the internal feed structure of FPGA to measure the time interval smaller than the system clock, which is combined with the pulse counting method to increase the range of the delay unit interpolation measurement. Finally, the FPGA is used to control the DAC7512 output voltage in real time to adjust the output of the local crystal based on the time interval output value. After a long time test, the accuracy of the synchronous 1PPS obtained by this method is better than 700ps compared with the standard 1PPS, and the local crystal can maintain a stable state for a long time.