| 摘要 |
PURPOSE:To prevent consumption of useless power by selecting a time interval of battery saving to be a 2nd time interval longer than the usual interval when a receiver is moved outside of a reception zone for a comparatively longer time. CONSTITUTION:An in-zone detection section 7 detects whether a current position of a receiver is within a reception zone or outside of the reception based on its decoding state or an electric field strength. When the receiver is within the reception zone, a power supply control section 8 implements battery saving in a 1st time interval as usual. When the receiver is outside of the reception zone, a built-in counter increments 1 to an out-zone detection number of times N. Then the out-zone detection number of times N is compared with a setting value A. In the case of N>=A, it is discriminated that the receiver is resident outside of the reception consecutively for a comparatively long time and battery saving at a 2nd time interval being a long time interval is implemented. |
