Single-conductor power line communications system
First Claim
1. A system for communicating digital information on a power line circuit having a plurality of conductors interconnecting at least one AC power source and at least one power-consuming load, comprising:
- at least one means, coupled to at least one of the conductors, for receiving a PLC signal and for controlling at least one controlled-power-consumption load responsive to the information received; and
at least one transmitter for forming the PLC signal by injection of a PLC signal current in series with only a single one of the power line conductors, and comprising;
input means for receiving digital information to be transmitted;
generator means for providing an output signal with (1) cyclic alternation between first and second states at a PLC frequency, at least two orders of magnitude greater than the AC source frequency, responsive to a first condition of the digital information at said input means, and (2) another selection of at least the second state, responsive to a second condition of the digital information at said input means;
switching means for providing a controllable impedance with respective low impedance and high impedance states responsive to respective first and second states of said output signal; and
saturable means for effectively coupling the switching means to the single conductor for injecting the PLC signal current therein only when the current in the single conductor is not greater than a saturation current level.
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Accused Products
Abstract
A power line communications (PLC) system utilizes a single conductor of a multiple-conductor power-transmission circuit, for carrying signal current, injected by at least one transmitter in series with that single conductor, to at least one receiver also coupled to that power line circuit. Each transmitter includes a saturable AC coupler connecting a switch to the conductor, while providing DC isolation therebetween. Each transmitter provides a signaling current having a frequency at least two orders of magnitude greater than the power line frequency, during at least some portion of each power line waveform signal cycle when the coupler is not saturated. Each transmitter preferably includes a power supply for providing transmitter operating potential responsive to the load current carried in that single conductor utilized for system signaling.
65 Citations
19 Claims
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1. A system for communicating digital information on a power line circuit having a plurality of conductors interconnecting at least one AC power source and at least one power-consuming load, comprising:
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at least one means, coupled to at least one of the conductors, for receiving a PLC signal and for controlling at least one controlled-power-consumption load responsive to the information received; and at least one transmitter for forming the PLC signal by injection of a PLC signal current in series with only a single one of the power line conductors, and comprising;
input means for receiving digital information to be transmitted;
generator means for providing an output signal with (1) cyclic alternation between first and second states at a PLC frequency, at least two orders of magnitude greater than the AC source frequency, responsive to a first condition of the digital information at said input means, and (2) another selection of at least the second state, responsive to a second condition of the digital information at said input means;
switching means for providing a controllable impedance with respective low impedance and high impedance states responsive to respective first and second states of said output signal; and
saturable means for effectively coupling the switching means to the single conductor for injecting the PLC signal current therein only when the current in the single conductor is not greater than a saturation current level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification