A radiofrequency (RF) wireline communications system includes an interference filter for filtering interference noise at a cable interface that couples a cable of the system to functional circuitry. The interference filter includes a first termination resistance element coupled between a first cable conductor and a system ground, and a first termination reactance element coupled to the first termination resistance element. The first termination reactance element has a first termination reactance value selected to direct signals on the first cable conductor, having predetermined frequency characteristics, away from the system ground, and the first termination resistance element has a first termination resistance value selected as a pull-down resistance for interference signals having other than the predetermined frequency characteristics, that are not directed by the first termination reactance element away from the system ground, to cause the interference signals, having other than the predetermined frequency characteristics, to propagate to the system ground.

Provided is an antenna device including an antenna unit including a rectifier circuit that receives electric field energy of a radio wave or a quasi-electrostatic field (near field) in a space and rectifies an AC signal into a direct current, the antenna unit including a first antenna element that is a conductor to be in contact with or connected to an industrial product metal portion and a second antenna element that is a conductor different from the first antenna element and provided not to be electrically connected to the industrial product metal portion, in which an input line output from the first antenna element to a rectifier circuit unit of the AC signal output from the antenna unit is connected to the rectifier circuit.

Provided is an antenna device including an antenna unit including a rectifier circuit that receives electric field energy of a radio wave or a quasi-electrostatic field (near field) in a space and rectifies an AC signal into a direct current, the antenna unit including a first antenna element that is a conductor to be in contact with or connected to an industrial product metal portion and a second antenna element that is a conductor different from the first antenna element and provided not to be electrically connected to the industrial product metal portion, in which an input line output from the first antenna element to a rectifier circuit unit of the AC signal output from the antenna unit is connected to the rectifier circuit.

A power-line/communication system including: (a) a power-line/communication bus comprised of first and second conductors; (b) one or more capacitor-based, receiver/transmitter nodes, parallel-connected to the first and second conductors; (c) a shunt capacitor parallel-connected to the first and second conductors; and (d) a current transformer having a secondary winding connected in series to the first conductor, which secondary winding is disposed between the shunt capacitor at one end thereof and the receiver/transmitter nodes at the other end thereof.

A power-line/communication system including: (a) a power-line/communication bus comprised of first and second conductors; (b) one or more capacitor-based, receiver/transmitter nodes, parallel-connected to the first and second conductors; (c) a shunt capacitor parallel-connected to the first and second conductors; and (d) a current transformer having a secondary winding connected in series to the first conductor, which secondary winding is disposed between the shunt capacitor at one end thereof and the receiver/transmitter nodes at the other end thereof.

Disclosed are one or more preferred geometric configurations for a device communicably coupled to a power transmission line and capable of launching transverse electromagnetic waves onto the transmission line. The waves propagate data received from a data source and may include a reflector and a coupler adjacent to each other through a transverse magnetic wave that propagates longitudinally along the surface of the transmission line.

An apparatus comprising a signal transformer coupled to a power line and a signal transmission, reception, or detection circuit. A sensor is configured to be responsive to the power line current or magnetic flux generated in a ferrite core of the signal transformer. When the sensor indicates that the flux generated by the power line current mat cause an attenuation of the signal strength, a second circuit generates a current through a flux cancelling winding that cancels at least some of the flux generated by the power line current.

A system for controlling a level of communication signals broadcast onto an associated power line communication (PLC) network by an associated transmitting device includes an input circuit, an adjustable amplifier circuit, and an output circuit. The input circuit receives a first communication signal having a first signal level from the associated transmitting device. The adjustable amplifier circuit applies a selectable gain to the first communication signal based on one or more of a monitored condition of the associated vehicle and/or a monitored condition of the associated PLC network to generate a level-adjusted communication signal having a second signal level different than the first signal level of the first communication signal. The output circuit receives the level-adjusted communication signal and broadcasts the level-adjusted communication signal onto the associated PLC network.

A system for controlling a level of communication signals broadcast onto an associated power line communication (PLC) network by an associated transmitting device includes an input circuit, an adjustable amplifier circuit, and an output circuit. The input circuit receives a first communication signal having a first signal level from the associated transmitting device. The adjustable amplifier circuit applies a selectable gain to the first communication signal based on one or more of a monitored condition of the associated vehicle and/or a monitored condition of the associated PLC network to generate a level-adjusted communication signal having a second signal level different than the first signal level of the first communication signal. The output circuit receives the level-adjusted communication signal and broadcasts the level-adjusted communication signal onto the associated PLC network.

A differential communication circuit is connected to a communication line formed of a positive communication line and a negative communication line for differential communication. The differential communication circuit includes: a series circuit that includes a resistor element and a connection switch. The resistor element is connected between the positive and negative communication lines when the connection switch is turned on. The circuit also includes a transmission unit that is configured to output a differential signal to the communication line and a controller that is configured to change impedance of the communication line by turning on the connection switch in a period during which the transmission unit does not output the differential signal.