| 摘要 |
PURPOSE:To attain guidance broadcast together with a starting bell by applying demodulation and amplification to a received signal and converting it into a voice signal through the changeover of a switch circuit in receiving a guide signal of a minute time and sounding the bell tone signal or a demodulated voice signal from a speaker. CONSTITUTION:In case of applying voice broadcast at a platform, a talk switch 16 of a transmission section 11 is turned on, a control circuit 18 generates a guide signal for a prescribed minute time tau only from an oscillation circuit 12 at first and an LED drive circuit 14 radiates an infrared LED 13a and a visual light LED 13b by an LED drive circuit 14 based on the guide signal. After a prescribed minute time tau elapses, the control circuit 18 of the transmission section 11 switches the switch circuit 17 to the position of the modulation circuit 19, and when a conductor utters contents such as guidance of destination of train and train change and getting on/off state of passengers toward a microphone 19a, then the guidance is converted into a voice signal by the microphone 19a, amplified by an amplifier 27 and broadcast from a speaker 28 as the voice.
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