SIGNAL COUPLING APPARATUS FOR PLC

PROBLEM TO BE SOLVED: To provide a signal coupling apparatus for a PLC capable of improving a transmission characteristic in the frequency band of a carrying signal without increasing a coupling degree in the low frequency band of a commercial frequency where a large current flows.SOLUTION: A signal coupling apparatus for a PLC used for transmitting a carrying signal in a high frequency band serving an electric power line 1 as a transmission line comprises: a magnetic body core 2 which is arranged so as to surround the circumference of the electric power line 1; a signal injection/extraction winding 3 which is wound around the magnetic body core 2 by at least one turn; a modem 4 for a PLC which is connected to the signal injection/extraction winding 3 and which transmits and receives the carrying signal; at least one second winding 5 wounded around the magnetic body core 2 by at least one turn; and one or more capacitors 6 which are connected to the second winding 5.