| 摘要 |
PURPOSE:To ensure an aural alarm, by displaying the drop of the power supply voltage in the transmission mode during receiving. CONSTITUTION:A radio machine consists of a battery power source 1, a microphone 5, a transmitting part 3, a transmitting antenna 6, a receiving antenna 7, a receiving part 4, a speaker 8, and a changeover switch 2 that carries out the switching between the parts 3 and 4 to supply the electric power. Furthermore, a low voltage alarm part 9 and a speaker 10 are added. The battery voltage is detected at the part 9 when the switch 2 is applied to the side of the part 3. In case the drop of the battery voltage is detected, an alarm is produced through a speaker 8 when the switch 2 is applied to the side of the part 4. Thus the alarm sound is never transmitted in the form of an electric wave. In such way, the drop of the power supply voltage in the transmission mode can be displayed in the form of a sound. |
