Abstract: An electric power line communication system operates with an electric power distribution system to provide through premises power distribution lines highly reliable communication links among receiving devices electrically coupled or located in proximity to the premises power distribution lines. A power line transceiver is designed to transmit and receive through the premises power distribution lines modulated carrier signals conveying information over the communication links. The power line transceiver operates in a transmitter mode as an intentional radiator to emit modulated carrier signals by transmitting them at a frequency band and a power level sufficient to form by electrical conduction a communication link with a modulated carrier signal receiving device.

Abstract: An electric power line communication system operates with an electric power distribution system to provide through premises power distribution lines highly reliable communication links among receiving devices electrically coupled or located in proximity to the premises power distribution lines. A power line transceiver is designed to transmit and receive through the premises power distribution lines modulated carrier signals conveying information over the communication links. The power line transceiver operates in a transmitter mode as an intentional radiator to emit modulated carrier signals by transmitting them at a frequency band and a power level sufficient to form by electrical conduction a communication link with a modulated carrier signal receiving device.

Abstract: An electric power line communication system operates with an electric power distribution system to provide through premises power distribution lines highly reliable communication links among receiving devices electrically coupled or located in proximity to the premises power distribution lines. A power line transceiver is designed to transmit and receive through the premises power distribution lines modulated carrier signals conveying information over the communication links. The power line transceiver operates in a transmitter mode as an intentional radiator to emit modulated carrier signals by transmitting them at a frequency band and a power level sufficient to form by electrical conduction a communication link with a modulated carrier signal receiving device.

Abstract: A power line carrier (PLC) communication system operating on a conventional three wire (Hot (H), Neutral (N) and Ground (G) wires) power line uses more than one of the several RF transmission lines that are defined by the three wire power line to improve communication between units of the PLC system. According to a first embodiment a PLC system transmitter sends out of phase RF signals across the H and G wires and across the N and G power wires to the PLC system receiver, which receives and combines both of the out of phase transmissions, and so even if one of these paths is severely attenuated, the other path can deliver a sufficiently strong RF signal to the receiver for effective communications. According to another embodiment three different pairs of the H, N and G wires of the power line are selected in sequence for transmission of the PLC system RF and the pair that results in the best communication between a system transmitter and receiver is used for continuing communication.

Abstract: In a control apparatus for a machine tool, a resolver interface circuit is utilized to determine whether or not the axis motors have driven the machine tool to the selected position. The resolver interface circuit synthesizes sine and cosine wave forms which are applied to a resolver which is mechanically coupled to the corresponding axis motor. The resolver interface circuit also synthesizes a signal which is phase related to the resolver excitation wave forms by the selected rotational displacement of the resolver and axis motor shafts required to achieve the selected position for the machine tool. The phase related signal and a positional feedback signal from the resolver are compared to generate an error signal to the driver for the axis motor. The selected position can be each incremental step where the axis motor is a stepping motor.