| 摘要 |
In a radio digital transmission system including at least one repeater station, a channel monitoring circuit of each repeater station comprises, besides the conventional inter-terminals fault detection circuit using a parity check system, a control bit inserting circuit (10) for inserting a parity control bit into the received signal, a control bit extracting circuit (7) for extracting the control bit from the received signal, a logic circuit (8) for logically operating the output signal of the conventional fault detection circuit and the output signal of the control bit extracting circuit (7), and a second fault detecting circuit (9) responsive to the output signal of the logic circuit (8) for detecting the fault on the transmitting line between the repeater station and an immediately preceding station. |
