| 摘要 |
<p>In a SLIC (1), line drivers (2,3) are connected with their inputs to respective outputs of a controllable current attenuator (6) whose input is supplied with transversal currents to be transmitted onto the transmission line (A,B), and with their outputs to respective wire of a two-wire transmission line (A,B). Means (4,9,10) are provided to detect any longitudinal currents on the transmission line (A,B) and to generate a current (I5,I6) to the inputs of the line drivers (2,3), that is proportional to a detected longitudinal current to counteract the same . Said means (4,9,10) is connected to a first input of a current comparator (5) having s second input connected to a reference current generator (7), and an output connected to a control input of the current attenuator (6). The current comparator (5) generates currents (I3) to control the current attenuator (6) to increase its attenuation when the current (I4) proportional to any longitudinal current on the transmission line exceeds the reference current (I9).</p> |
