| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To achieve complete time synchronization with a master device in a slave device. <P>SOLUTION: In the slave device 120, a first value (Offset) which is a time offset between itself and the master device 110 is calculated, and correction is performed so that a time of a timepiece part agrees with a value determined by being subtracted as much as the first value ((a)-(i)). In the slave device 120, a second value t6' which is a predicted value of a time when a message issued at a time t5 is received by the master device 110 is calculated, and compared with an actual arrival time t6, and a frequency of a count clock of the timepiece part is heightened if t6'<t6, and is lowered in the reverse case ((j)-(P)). Since time correction and clock frequency correction of the timepiece part are repeated, the time of the slave device 120 always agrees with the time of the master device 110 as well as during an offset correction time, to thereby achieve complete time synchronization with the master device 110 in the slave device 120. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
