| 摘要 |
PURPOSE:To extend the life of a battery and improve the probability of receiving, by turning on the power source of a radio part in the time, when a synchronizing signal is received plural number of times, only when the receiver is asynchronous with a transmission signal. CONSTITUTION:When a power supply switch 22 is turned on, a power rise detecting circuit 24 detects the rise of the power to output an output signal (f), and therefore, a timing circuit 26 generates an output in the time when a frame synchronizing signal can be received plural times, and a power supply control part 23 is driven to supply the power to a radio part 12. When the electric field becomes weak and the frame synchronizing signal cannot be received, a frame out-of synchronization detecting circuit 18 outputs an output signal (d), and therefore, the timing circuit 26 generates an output in the time, when the frame synchronizing signal is received plural number of times, similarly to the case of the power rise, and the power is supplied to the radio part 12. If the frame synchronizing signal is not received in this time, the power source of the radio part 12 is turned off. |
