JPS5634252A - Time synchronization control system - Google Patents

Abstract

PURPOSE:To improve the absolute time precision of sample values in each observation station, by time-synchronizing the internal counter of each observation station with the internal counter of the center station in the earthquake observation system and so on. CONSTITUTION:Center station 1 is provided with internal counter 12 which generates the internal clock synchronized with the clock of master clock generator 11 corrected by the absolute time, and observation station 2 is provided with internal counter 22 which generates internal clocks controlled by variable frequency oscillator 21. Counter 22 generates a signal of the same period as the clock from counter 12. The frame signal is transmitted from station 2 at internal clock time (o), and the arrival time is counted on a basis of the internal clock by time measuring circuit 17 in station 1, and the lapse time from time (o) is obtained, and the local frame signal is transmitted the lapse time before from time (o). In station 2, the frame signal from station 1 is counted on the basis of the local internal clock by time measuring circuit 27, and oscillator 21 is so controlled that the 1/2 of the lapse time from time (o) may be a prescribed value, and the time error between internal counters of both stations is set to zero.