| 摘要 |
The invention concerns feeding current to a subscriber set. In addition to an isolation transformer (T) the transmission bridge includes a measuring circuit (4) connected to the subscriber line, and a receive circuit (7), with the measuring circuit connected to the receive circuit via an impedance adjusting circuit (6). The receive circuit is connected to a receive terminal (10) and is arranged to forward the signal received therefrom to the transformer. The bridge also includes a send circuit (9), likewise connected to the measuring circuit and receiving the signal at the receive terminal via a balance circuit (8) for cancelling the signal delivered by the send circuit while the subscriber set is receiving. Application to telephony. |
