| 摘要 |
PCT No. PCT/SE83/00333 Sec. 371 Date May 4, 1984 Sec. 102(e) Date May 4, 1984 PCT Filed Sep. 22, 1983 PCT Pub. No. WO84/01250 PCT Pub. Date Mar. 29, 1984.An apparatus for supplying current to a subscriber telephone set (RL) connected to a telephone exchange via a two-wire line departing from a a-wire and a b-wire output terminal in the arrangement. The arrangement includes two analogue amplifiers (2, 3) each with its output connected to said respective a-wire and b-wire output terminal, through which the combined DC-current and current representing the speech signal are fed out to the line. The apparatus further includes a voltage source with the pole voltage (EB) and its poles connected to two voltage supply inputs on each amplifier (2, 3), the output of the first amplifier (2, 3) being kept at a fixed potential. Three signal sources (5, 6, 8) are connected to the inputs of the amplifiers, the respective signal contribution of these sources being added for controlling the output magnitudes of the amplifiers. A first signal source (6) constitutes the reference signal source and has a fixed signal contribution. A second signal source (5) is controlled by the output magnitudes of the amplifiers, and a third signal source (8) is controlled by the difference between the transversal line voltage and the actual voltage (EB). |
