US 4,471,399 A · Power-line baseband communication system

Abstract

A communication system for transmitting baseband digital signals on an electrical power line. A pulse generator produces digital signals which are limited to a frequency spectrum of 30 kHz to 300 kHz and applied directly, i.e., without modulation, to an electrical power line. At the receiving terminal an amplifier compensates for attenuation characteristics of the electrical power line and the received signal is then sampled to extract the information from it. To avoid interference when both a transmitting and receiving link are located at a substation, the baseband system incorporates a mimic network to mimic the interference signal erroneously picked up by the receiving link from the transmitting link located at the same substation. The mimic signal is then subtracted from the interference signal to neutralize the effect of the latter. When both a baseband digital communication system and a carrier communication system utilize the same electrical power lines, provision is made for interrupting the baseband digital signal to allow communications via the carrier system.

Claims36

Dependent claims

A power-line data system for conveying communication signals over a power-line conductor having a characteristic line transfer function, said power-line data system comprising:

means for producing a digital information signal having a plurality of zero and one bits;
pulse generator means being adapted for coupling to said power-line conductor at a first location, said pulse generator means for propagating a baseband digital signal representative of said digital information signal over said power-line conductor wherein said baseband digital signal has a first, a second, and a third state, and wherein each one of the plurality of binary zero bits is represented by said first state, and wherein a first bit of two consecutive bits of the plurality of binary one bits is represented by said second state, and wherein a second bit of two consecutive bits of the plurality of binary one bits is represented by said third state;
and
sampling bit detector means being adapted for coupling to said power-line conductor at a second location, for receiving said baseband digital signal, and for producing an output signal in response thereto.

1 more element

A power-line data system for conveying communication signals over a first and a second power transmission line, said first and said second transmission lines connected together at a power bus, said power line data system comprising:

first pulse generator means being adapted for coupling to said first transmission line for propagating a first baseband digital signal in response to a first information signal over said first transmission line, wherein said first baseband digital signal has a primary component and a run-around component;
first sampling bit detector means being adapted for coupling to said first transmission line for receiving said primary component of said first baseband digital signal and for producing a first output signal in response thereto;
second pulse generator means being adapted for coupling to said second transmission line for transmitting a second baseband digital signal in response to a second information signal;
second sampling bit detector means being adapted for coupling to said second transmission line for receiving said second baseband digital signal and for producing a second output signal in response thereto, and wherein said run-around component of said first baseband digital signal is coupled to said second sampling bit detector means via said power bus, such that said run-around component interferes with proper detection of said second baseband digital signal.

1 more element

Dependencies are inferred from the claim text.

Power-line baseband communication system

Life of this patent

Power-line baseband communication system

Life of this patent

Abstract

Claims36