| 摘要 |
<P>PROBLEM TO BE SOLVED: To make hard to be influenced by an attack radio wave or an interference radio wave in a system wherein an accurate time is transmitted by radio wave among a plurality of devices. <P>SOLUTION: When receiving time information from a high-order device by a receiver 31, a control part 33 calculates a relative progress between a time designated by the time information received this time and a time clocked by a clocking part 34, and determines a tolerance of the relative progress at this time from a mean value and a standard deviation value of the history of the relative progress. When the relative progress at this time is within the tolerance, the clocked time by the clocking part 34 is corrected to the time designated by the received time information, and the time information is transmitted to a low-order device. When the relative progress at this time is out of the tolerance, the information is discriminated to be abnormal, and correction of the clocking part 34 and transmission of the time information to the low-order device are not performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
