| 摘要 |
PURPOSE:To attain stable data communication over a long time while suppressing power consumption of a battery by providing a communication power control means controlling a transmission power in the data communication based on the communication distance from an external device. CONSTITUTION:The setting of a transmission power by a transmission power setting section 1 is awaited, and after the transmission power is set, the transmission power is outputted to a transmission power control section 4. Then a control section 2 outputs a communication data to a radio module section 3, which applied prescribed modulation to a communication data (voltage information of a battery 6 is included in the data) and a data is sent in a radio wave from an antenna 5. When the communication with an external device is started, a communication power control means 4 controls the transmission power based on the communication distance. Thus, stable data radio communication is implemented while suppressing power consumption of a battery as the communication distance from an external device is near. |
