| 摘要 |
PURPOSE:To attain inexpensive and small sized line supervision by inputting a signal to supervise plural lines to a supervision signal detection section of one system in time division, and identifying a detection signal in space division. CONSTITUTION:The level of a signal from a modulator 11 and a demodulator 13 is adjusted by a time dividing circuit 21, subject to time division and detected by a detecting circuit through a BPF(Band Pass Filter) 22. Then whether a signal comes from the modulator 11 or the demodulator 13 is identified by a space dividing circuit 24 and each output is sent from terminals 31, 33. Thus, the BPF 22 and the detection circuit 23 are used in common, the constitution is simplified and a small sized and inexpensive supervision signal detection circuit is obtained. |
