| 摘要 |
At least one two-wire/four-wire hybrid coupling is used for connection of transmission and reception paths to a two-wire line (L1,L2). This line connects the paths to a subscriber appts. which receives direct current from the fork coupling. Circuit components (Rp1-Rp4) are provided to hold the feed current (10) within a specific interval. Amplifiers in the transmission and reception paths have controllable amplification, and a circuit arrangement (DF) is connected into the fork coupling to form a control dimension which is dependent upon the line length between the transmitter and the subscriber appts. This control dimension is provided to the amplifiers so that for short line lengths amplification is low, and for long lengths it is high. A differential amplifier (DF) has inputs (a,b) connected to the circuit components (Rp1-Rp4) to monitor a voltage which is dependent upon the line length and on whose output connectable to the controllable amplifiers to adjust amplification in terms of line length. (Provisional basic advised week 86/11) |
