Powerline carrier control system with powerline current compensation
First Claim
1. A powerline carrier control system comprising a powerline carrier control transmitter for generating a keyed output voltage at audio frequency to be supplied to an AC powerline that has a predetermined line-frequency, and coupling means comprising a first side connected to said transmitter and a second side connected to said powerline to transfer said keyed output voltage to said powerline, said system comprising:
- a. control signal generating means to generate a control signal at said line-frequency, said control signal corresponding to a back AC signal at said line-frequency transmitted from said powerline through said coupling means; and
b. superimposing means connected to said control signal generating means to be controlled by said control signal, said superimposing means being connected to said powerline carrier control transmitter to superimpose, on said keyed output voltage at audio frequency therefrom, a compensating voltage at a controlled amplitude and phase relative to said back signal and in opposition thereto to reduce substantially the flow of current at said predetermined line-frequency from said powerline through said powerline carrier control transmitter.
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Accused Products
Abstract
In a powerline carrier control system, a powerline carrier control transmitter delivers an audio frequency voltage to the powerline carrier control receivers via a coupling unit and AC supply network. The coupling unit consists of a coupling transformer and an L-C combination which would normally insure that the network AC voltage is kept completely away from the powerline carrier control transmitter. In the system disclosed, back voltage is intentionally permitted and a supplementary AC voltage of line frequency is superimposed on the transmitter output voltage to buck the back voltage and thereby prevent current at the line frequency from the AC network from flowing through the transmitter. This simplifies and reduces the cost of the heretofore expensive components of the L-C combination.
26 Citations
6 Claims
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1. A powerline carrier control system comprising a powerline carrier control transmitter for generating a keyed output voltage at audio frequency to be supplied to an AC powerline that has a predetermined line-frequency, and coupling means comprising a first side connected to said transmitter and a second side connected to said powerline to transfer said keyed output voltage to said powerline, said system comprising:
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a. control signal generating means to generate a control signal at said line-frequency, said control signal corresponding to a back AC signal at said line-frequency transmitted from said powerline through said coupling means; and b. superimposing means connected to said control signal generating means to be controlled by said control signal, said superimposing means being connected to said powerline carrier control transmitter to superimpose, on said keyed output voltage at audio frequency therefrom, a compensating voltage at a controlled amplitude and phase relative to said back signal and in opposition thereto to reduce substantially the flow of current at said predetermined line-frequency from said powerline through said powerline carrier control transmitter. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification