| 摘要 |
PURPOSE:To evade a going-around fault between relay stations by transmitting a station selection signal to the relay stations from a master station, permitting the selected relay station to receive and catch up on delay, enabling a moving station to respond and differing the levels that the relay stations respond to the master station. CONSTITUTION:When a receiver 1 receives a frequency f1 which is modulated by a frequency S1 selecting the relay station A from the master station, a receiver 2 operates a delay catch-up-on unit 4, closes a switch 8, and transmits a signal with a frequency f2 to the moving station from a transmitter 5. The unit 4 maintains the relay station A operable in a given length of time. With response from the moving station found, a receiver 6 receives it, and a transmitter 7 transmits it. An attenuator 8 suppresses an output to the master station, so that the master station will not receive a signal relayed through the relay stations A and B. When a signal to the relay station B is received, a receiver 4 operates to open the switch in the unit 4, and hence the relay station A makes no response to the master station. With this constitution, the relay station that functions due to the specification of the master station is selected, and the selection is maintained as long as response from the slave station is founed in a specified time.
|
