Patent ID: 7318166

Claim:
A synchronization method for synchronizing an internal time of a system clock of a computer with an external reference clock, comprising: detecting a signal for time notice sent from said reference clock and acquiring the internal time at the present time from said system clock by said computer; calculating a signal interval that is a time difference in said system clock between two consecutive signals for time notice based on said acquired internal time by said computer; evaluating said calculated signal interval and judging whether or not to correct said internal time by said computer; and correcting the time of said system clock when it is judged that said computer is required to correct said internal time, wherein the synchronization method is provided as a user process of an operating system of the computer, wherein judging whether or not to correct said internal time is based on whether said calculated signal interval falls within a certain confidence interval obtained by a statistical processing of sampling the signal over the past signal intervals by said computer.