POWER LINE COMMUNICATIONS TERMINAL AND INTERFACE CIRCUIT ASSOCIATED THEREWITH

摘要

16 A communications terminal for transmitting and receiving communication signals over a power line communications network and including an interface circuit for coupling the terminal to the power line of the network is disclosed. One embodiment of the network includes a transformer for coupling communication signals between the power line and terminal. The coupled communication signals are measured from the secondary of the transformer and used to govern an amplifier circuit which generates matched signals, representative of the measured communication signals. The matched signals are inverted in polarity at the output stage of the amplifier and applied to the secondary winding of the transformer to cancel substantially the electromagnetically coupled communication signals from the power line, thereby providing a high bridging impedance to the power line communication signals without impeding substantially the coupling of the terminal's own communication signals.