| 摘要 |
PURPOSE:To realize the efective use of an electric wave, by continuing the transmission of own station, and locking the transmission during the transmission of other stations, when monitoring by single wave in common with each station. CONSTITUTION:When an alarm signal is transmitted from an input part 11 of a slave station RT, a transmission deciding part 13 starts a pilot oscillating part 14 and opens an AND gate 15. Thus the alarm signal is transmitted via the gate 15, and at the same time a pilot signal is also transmitted from the part 14. A master station CT demodulates and decodes the alarm signal sent from the slave station through a demodulating part 8 and applies it to a reception output part 6 to light up an alarm lamp, etc. At the same time, a carrier detectig signal is applied to a transmission deciding part 3 from a carrier detecting part 7. Then an AND gate 5 is closed through the part 3, and as a result the transmission is locked for the master station. The signal transmitted from a slave station is sent back to the slave station via a master station. The slave station detects the signals at a carrier detecting part 17 and a pilot detecting part 19 and closes a gate 20 to detect the transmission. |
