| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption and to accelerate synchronizing probability by selecting the switching of a channel according to judgment on whether moving to outside of a circle is caused by outside of a transmission area or an obstacle from the presence/absence of a synchronous signal, just prior to moving to the outside of a receiving circle so as to make frequency scanning efficient. SOLUTION: A synchronization monitoring part 108 detects a synchronizing signal by a synchronizing pattern (d), detected from a demodulation signal (b) by a synchronization detection part 104 and sends data (f) to a control part 106. At the time of judging that moving to outside of the circle is caused by the disconnection of radio waves by data (f) and synchronization detecting data (g) for prescribed number of times held by a history holding part 109, the part 106 does not switch the frequency but at the time of going out from the transmission area, set the retrieval of the synchronizing signal while successively switching a frequency channel. Thereby power consumption at the time of scanning the frequency is reduced, and synchronization within the circle is speedily establishes at the time of moving to outside of the circle. |
