| 摘要 |
PROBLEM TO BE SOLVED: To attain a small sized lightweight device convenient for carrying by reducing the power consumption of the device when it is resident at the outside of a communication zone. SOLUTION: An SW section 2 outputs a received signal from an antenna 1 to a transmission reception section 3 or a specific frequency field strength detection section 14, which detects the electric field strength. On the other hand, a power supply control section 13 in a control unit 8 controls the SW section 2 based on the discrimination result and the result of detection by the detection section 14 and activates only the specific frequency field strength detection section 14 when a mobile station is resident at the outside of a communication zone and inactivates the transmission reception section 3. |
