Device for sending and receiving data through power distribution transformers

A power line communication system for transmitting a data signal over power lines carrying a power signal having a power-line frequency, the system comprising:

• (1) a transmitter comprising a pair of terminals for coupling the transmitter to the power lines, and a carrier frequency generator for continuously calculating a carrier frequency as a function of the power-line frequency for adaptively tracking changes in the power-line frequency, said carrier frequency generator having a synchronization input for connection to the power lines and wherein said transmitter generates a carrier signal having said carrier frequency and provides said carrier signal to said terminals and (2) a receiver for connection to the power lines, the receiver comprising a filter means for filtering the carrier signal from the power signal, a demodulator for extracting the data signal from the carrier signal, and a synchronization input for connection to the power lines, said receiver continuously generating a carrier decode frequency as a function of the power-line frequency for adaptively tracking changes in the power-line frequency and for demodulating the carrier signal, wherein both the demodulator and carrier frequency generator utilize a digital algorithm for calculating the carrier frequency and the carrier decode frequency.

A power line communication system for transmitting a data signal over power lines carrying a power signal, the system comprising:

• (1) a transmitter comprising a pair of terminals for coupling the transmitter to the power lines, a pair of switches connected across the pair of terminals, for applying a carrier signal having a carrier frequency modulated with a data signal to the pair of terminals, a resonant circuit including capacitive and inductive elements and connected to said pair of switches for reducing current and voltage transients, and a carrier frequency generator connected to and controlling the pair of switches to control the frequency of the carrier signal;
• and (2) a receiver, for connection to the power lines and comprising a filter means for filtering the carrier signal from the power line signal, and a demodulator connected to the filter means for extracting the data signal from the carrier signal.

A transmitter, for transmitting a carrier signal modulated with a data signal over power lines carrying a power signal having a power-line frequency, the transmitter having terminals for connection to power lines and comprising at least two of:

• (1) a first resonant circuit connected to the terminals and being substantially resonant at the frequency of the carrier;
• (2) a carrier frequency generator including a synchronization input for connection to the power lines, said generator continuously calculating the carrier frequency as a function of the power-line frequency via a digital algorithm for adaptively tracking changes in the power-line frequency;
• and (3) a switching circuit for generating a carrier signal having a carrier frequency modulated by the data signal, said switching circuit comprising at least one storage means for storing energy when generating a portion of a cycle of said carrier signal and providing said stored energy when generating another portion of said cycle of said carrier signal.

A receiver for connection to power lines for receiving a data signal encoded in a carrier signal, the receiver comprising:

• a filter means for filtering the carrier signal from the power line signal;
• and a demodulator connected to the filter means, for extracting the data signal from the carrier signal, said demodulator comprising a computing device having a synchronization input for connection to the power lines for continuously generating a carrier decode frequency as a function of the power-line frequency for adaptively tracking changes in the power-line frequency and for demodulating the carrier signal, and a phase detector controlled by the computing device, for detecting a phase difference between the carrier decode frequency generated by the computing device and the frequency of the carrier signal, whereby the computing device can switch the carrier decode frequency to the frequency of the carrier signal, thereby to extract the data signal from the carrier signal.

A method of transmitting a data signal over power lines, the method comprising generating a carrier signal having a carrier frequency modulated with the data signal, applying the modulated carrier signal to the power lines at one location and receiving and demodulating the carrier signal at another location, the method comprising at least two of:

• (1) resonantly coupling the carrier signal to the power lines using a first resonant circuit;
• (2) continuously digitally calculating the carrier frequency as a function of the power-line frequency for adaptively tracking changes in the power-line frequency;
• and, (3) generating the carrier signal via a switching circuit, which includes storing energy when generating a portion of a cycle of said carrier signal and providing said stored energy when generating another portion of said cycle of said carrier signal.

A power line communication system for transmitting a data signal over power lines carrying a power signal having a power-line frequency, the system comprising:

• (1) a transmitter comprising a pair of terminals for coupling to the power lines, and a carrier frequency generator including a digital computing device for continuously calculating a carrier frequency as a function of the power-line frequency for adaptively tracking changes in the power-line frequency, the carrier frequency generator having a synchronization input for connection to the power lines and the transmitter generating a carrier signal having the carrier frequency and providing the carrier signal to the terminals;
• and (2) a receiver for connection to the power lines, the receiver comprising a filter means for filtering the carrier signal from the power line signal, and a demodulator including a digital computing device for extracting the data signal from the carrier signal.