| 摘要 |
PURPOSE:To perform a circuit test without receiving limitation of the circuit distance by adding a switch means, a DC power supply for circuit test, an oscillator, a selection detecting means and a BPF or a code converter to each reproduction repeater. CONSTITUTION:The reproduction repeaters 6 and 7 contain relays RL1 and RL2, DC power supplies 6a and 7a, oscillators 6b and 7b, selection detecting relays 6c and 7c, and BPFs or code converters FL0-FL2 respectively. Both repeaters form a loop circuit including BPFs or code converters with the reproduction repeaters of the next stage by the functions of relays RL1 and RL2. At the same time, the loop circuit is connected to the DC power supply and the relay of the reproduction repeater of the next stage. The outputs of the oscillators 6b and 7b of the preceding stage are returned by a loop formed to the reproduction repeater of the next stage. Then the selection detecting relay detects the presence or absence of the returned signal. |
