TIME STAMP DEVICE, TIME CALIBRATION METHOD, AND TIME CALIBRATION PROGRAM

摘要

A local time generated by a local time generation unit is calibrated by an authentication time acquisition unit by using an authentication time acquired from a time issuing device. A time calibration unit calculates a delay time contained in the authentication time according to a response time from the moment when the authentication time acquisition unit requests the time issuing device to issue an authentication time until the moment when the authentication time acquisition unit acquires the authentication time. The time calibration unit judges whether the calculated delay time exceeds a predetermined threshold value and calibrates the local time by using the authentication time received from the time issuing device.