| 摘要 |
An electronic external line repeater connects a two-wire side to two four-wire sides. The repeater contains two optocouplers (FT1-D1, FT2-D2). A self-compensating negative feedback circuit is connected in accordance with the invention from the two-wire side to the incoming four-wire side. Initial spread and age degradation in the optocoupler (FT2-D2) is thus counteracted. The feedback circuit contains a lowpass filtering and comparing circuit (F3) connected to the line amplifier (F2) of the repeater. |
