Transformer coupler for communication over various lines

• US 6,104,707 A
• Filed: 03/14/1997
• Issued: 08/15/2000
• Est. Priority Date: 04/28/1989
• Status: Expired due to Fees

• Current Assignee: Satius Holding, Inc. (Satius, Inc.)
• Original Assignee: Videocom, Inc.
• Inventors: Abraham, Charles
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US08/818,817
• Time in Patent Office: 1,250 Days
• Field of Search: 370/295, 370/281, 370/485, 375/222, 307/3, 307/104, 307/140, 340/310.01, 340/310.02, 340/310.03, 340/310.05, 340/310.06, 340/310.07, 340/531, 333/177, 336/182, 336/200, 379/443, 379/444
• US Class Current: 370/295
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5433 Remote metering
• CPC Class Codes: H04B 2203/5437 Wired telephone
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 2203/5491 using filtering and bypassing
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission

Abstract

An apparatus for electrical line communication includes a transmitter, a receiver, a modem, and a coupler at each of two or more locations along an electrical line. The couplers have capacitive circuits serially connected with an air-core transformer. The capacitive circuits resonate with the air-core transformer at a preselected frequency. A novel phase linear coupler eliminates noise and is matched resistively to the characteristic impedance of the line at the preselected frequency, which linearizes communication on the line and allows high speed data and voice communication over long distances.

Claims

1. A communications apparatus for communicating electrical signals through an electric power line having a characteristic impedance comprising:

modulator means for modulating the electrical signals to produce a modulated carrier signal having a first pre-selected frequency;

transmitter means having an output impedance electrically connected to said modulator means for transmitting the modulated carrier signal;

first coupler means adapted to be connected between the electric power line and the transmitter means for matching the output impedance of said transmitter means to the characteristic impedance of the electrical line, said first coupler means comprising linear phase means for communicating the modulated carrier signal to the electric power line without significant phase distortion and capacitor means for resonating with the linear phase means at the first pre-selected frequency;

receiver means having an input impedance for receiving the modulated carrier signal;

demodulator means electrically connected to said receiver means for demodulating said modulated carrier signal to produce a demodulated carrier signal having a second pre-selected frequency; and

second coupler means adapted to be connected between the electrical power line and the receiver means for matching the input impedance of said receiver means to the characteristic impedance of the electric power line, said second coupler means comprising linear phase means for communicating the modulated carrier signal to the receiver means without significant phase distortion and capacitor means for resonating with the linear phase means at the second pre-selected frequency;

said linear phase means of said first and second coupler means comprising an air-core transformer;

said air-core transformer comprising;

a primary coil having a first diameter;

a secondary coil having a second smaller diameter, said secondary coil extending coaxially within said primary coil such that an air gap is created between said primary and said secondary coils;

capacitor means connected between said primary coil and said electrical line, wherein said primary coil and said capacitor means are matched to the characteristic impedance of said electrical line at a pre-selected bandwidth;

said primary coil having a resistive component, said resistive component of said primary coil of said first coupler means being about 1 ohm and said resistive component of said primary coil of said second coupler means being about 3 ohms for full duplex communications.

2. The communications apparatus of claim 1 wherein said primary coil has a resistive component, said resistive component of said primary coil of said first coupler means is about 1 ohm and said resistive component of said primary coil of said second coupler means is about 1 ohm for half duplex communications.

3. The communications apparatus of claim 1 wherein said electrical line is a high voltage power line and said primary coil has a resistive component, said resistive component of said primary coil of said first coupler means is about 5 ohms and said resistive component of said primary coil of said second coupler means is about 10 ohms for full duplex communications.

4. The communications apparatus of claim 1 wherein said electrical line is a high voltage power line and said primary coil has a resistive component, said resistive component of said primary coil of said first coupler means is about 5 ohms and said resistive component of said primary coil of said second coupler means is about 5 ohms for half duplex communications.

5. The communications apparatus of claim 1 wherein the modulator means further comprise a synthesizer for generating a local oscillator signal and a mixer for mixing the modulated carrier signal at the first preselected frequency with the local oscillator signal for generating a modulated carrier signal at an alternative frequency which is shifted from the first preselected frequency.

6. A communication apparatus for communicating electrical signals through a pair of electrical lines having a characteristic impedance comprising:

first modem means for producing a modulated carrier signal having a first preselected frequency and demodulating a modulated carrier signal having a second preselected frequency;

first transmitter means having an output impedance, connected to the first modem means for transmitting the modulated carrier signal at the first preselected frequency;

first receiver means having an input impedance, connected to the first modem means for receiving the modulated carrier signal having the second preselected frequency;

first coupler means connected between the pair of electrical lines and said first transmitter and receiver means for matching the impedance of said means to the characteristic impedance of the pair of electrical lines and for communicating the carrier signals without substantial phase distortion;

second modem means for producing a modulated carrier signal having the second preselected frequency and demodulating a modulated carrier signal having the first preselected frequency;

second transmitter means having an output impedance, connected to the second modem means, for transmitting the modulated carrier signal at the second preselected frequency;

second receiver means having an input impedance, connected to the second modem means, for receiving the modulated carrier signal having the first preselected frequency; and

second coupler means connected between the electrical lines and said second transmitter and receiver means for matching the impedance of said devices to the characteristic impedance of the electrical lines and for communicating the carrier signals without substantial phase distortion.

7. The communications apparatus of claim 6 wherein said first and second coupler means communicate the carrier signals having preselected frequencies less than 35 KHz each and a linear phase bandwidth of approximately 6 KHz.

8. The communications apparatus of claim 6 wherein said first coupler means comprises two LCR circuits.

9. The communications apparatus of claim 8 wherein each of the LCR circuits comprises at least one capacitor and at least one resistor, connected in parallel to each other and in series to the electrical lines, and a linear phase means.

10. The communications apparatus of claim 9 wherein the linear phase means comprises air-core transformer means.

11. The communications apparatus of claim 10 wherein said air-core transformer means comprises:

a primary coil having a first diameter; and

a secondary coil having a second, smaller diameter, said secondary coil extending coaxially within said primary coil such that an air-gap is created between said primary and said secondary coils.

12. The communications apparatus of claim 6 wherein said second coupler means comprises two LCR circuits.

13. The communications apparatus of claim 12 wherein each of the LCR circuits comprises at least one capacitor and at least one resistor connected in parallel to each other and in series to the electrical lines, and a linear phase means.

14. The communications apparatus of claim 13 wherein the linear phase means comprises air-core transformer means.

15. The communications apparatus of claim 14 wherein said air-core transformer means comprises:

a primary coil having a first diameter; and

a secondary coil having a second, smaller diameter, said secondary coil extending coaxially within said primary coil such that an air-gap is created between said primary and said secondary coils.

16. The communications apparatus of claim 6 wherein the first modem means includes means for shifting the frequency of the modulated carrier frequency from the first preselected frequency to an alternative frequency.

17. The communications apparatus of claim 16 wherein the second modem means includes means for shifting the frequency of the modulated carrier frequency from the second preselected frequency in order to avoid interference on the pair of electrical lines.

18. A communication apparatus for communicating electrical signals through a pair of electrical lines having a characteristic impedance comprising:

first modem means for producing a modulated carrier signal having a first preselected frequency and demodulating a modulated carrier signal having a second preselected frequency;

first transmitter means having an output impedance, connected to the first modem means, for transmitting the modulated carrier signal at the first preselected frequency;

first receiver means having an input impedance, connected to the first modem means, for receiving the modulated carrier signal having the second preselected frequency;

first coupler means connected between the pair of electrical lines and said first transmitter and receiver means for matching the impedance of said first transmitter and receiver means to the characteristic impedance of the pair of electrical lines, said first coupler means comprising two LCR circuits, each of the LCR circuits comprising at least one capacitor and at least one resistor connected in parallel to each other and in series to the pair of electrical lines and a linear phase means for communicating the carrier signals without significant phase distortion;

second modem means for producing a modulated carrier signal having the second preselected frequency and demodulating a modulated carrier signal having the first preselected frequency;

second transmitter means having an output impedance, connected to the second modem means, for transmitting the modulated carrier signal at the second preselected frequency;

second receiver means having an input impedance, connected to the second modem means, for receiving the modulated carrier signal having the first preselected frequency;

second coupler means connected between the pair of electrical lines and said second transmitter and receiver means for matching the impedance of said second transmitter and receiver means to the characteristic impedance of the pair of electrical lines, said second coupler means comprising two LCR circuits, each of the LCR circuits comprising at least one capacitor and at least one resistor connected in parallel to each other and in series to the pair of electrical lines and a linear phase means for communicating the carrier signals without significant phase distortion.

19. The communications apparatus of claim 18 wherein the linear phase means of the first and second coupler means each comprises air-core transformer means comprising:

a primary coil having a first diameter;

a secondary coil having a second smaller diameter, said secondary coil extending coaxially within said primary coil such that an air gap is created between said primary and said secondary coils; and

capacitor means connected between said primary coil and the pair of electrical lines, wherein said primary coil and said capacitor means are matched to the characteristic impedance of said pair of electrical lines at a preselected bandwidth and said primary coil has a resistive component.

20. The communications apparatus of claim 19 wherein for full duplex communications, the resistive component of said primary coil connected to said transmitter means is about 1 ohm and the resistive component of said primary coil connected to said receiver means is about 3 ohms.

21. The communications apparatus of claim 19 wherein for half duplex communications, the resistive component of said primary coil connected to said transmitter means is about 1 ohm and the resistive component of said primary coil of said receiver means is about 1 ohm.

22. The communications apparatus of claim 19 wherein the pair of electrical lines comprise a high voltage power line, wherein for full duplex communications, the resistive component of said primary coil connected to each of said first and second transmitter means is about 5 ohms and the resistive component of said primary coil connected to each of said first and second receiver means is about 10 ohms.

23. The communications apparatus of claim 19 wherein the pair of electrical lines comprise a high voltage power line, wherein for half duplex communications, the resistive component of said primary coil connected to each of said first and second transmitter means is about 5 ohms and the resistive component of said primary coil connected to each of said first and second receiver means is about 5 ohms.

24. The communications apparatus of claim 18 wherein the first modem means includes means for shifting the frequency of the modulated carrier frequency from the first preselected frequency to an alternative frequency.

25. The communications apparatus of claim 24 wherein the second modem means includes means for shifting the frequency of the modulated carrier frequency from the second preselected frequency in order to avoid interference on the pair of electrical lines.

26. A communications apparatus for communicating electrical signals through an electrical line having a characteristic impedance comprising:

modulator means for modulating the electrical signals to produce a modulated carrier signal having a preselected frequency;

transmitter means having an output impedance, connected to the modulator means for transmitting the modulated carrier signal;

first coupler means connected between the electrical line and the transmitter means for matching the output impedance of the transmitter means to the characteristic impedance of the electrical line, the first coupler means comprising linear phase means for communicating the modulated carrier signal to the electrical line without substantial phase distortion and capacitor means for resonating with the linear phase means at the preselected frequency;

demodulator means for demodulating the carrier signal on the electrical lines to produce a demodulated carrier signal having the preselected frequency;

receiver means having an input impedance connected to the demodulator means for receiving the modulated carrier signal;

second coupler means connected between the electrical line and the receiver means for matching the input impedance of the receiver means to the characteristic impedance of the electrical line, the second coupler means comprising linear phase means for communicating the modulated carrier signal to the receiver means without substantial phase distortion and capacitor means for resonating with the linear phase means at the preselected frequency, wherein the linear phase means for each of the first and second coupler means comprises air-core transformer means comprising a primary coil having a first diameter, a secondary coil having a second smaller diameter, the secondary coil extending coaxially within the primary coil such that an air-gap is created between the primary and the secondary coils, and capacitor means connected between the primary coil and the electrical line wherein the primary coil and the capacitor means are matched to the characteristic impedance of the electrical line at a preselected bandwidth, wherein the primary coil includes a resistive component, and wherein for half duplex communications, the resistive component of the primary coil connected to the transmitter means is around 1 ohm and the resistive component of the primary coil connected to the receiver means is around 1 ohm.

27. A communications apparatus for communicating electrical signals through an electric line having a characteristic impedance comprising:

modulator means for modulating the electrical signals to produce a modulated carrier signal having a first preselected frequency;

transmitter means having an output impedance electrically connected to said modulator means for transmitting the modulated carrier signal;

first coupler means adapted to be connected between the electric line and the transmitter means for matching the output impedance of said transmitter means to the characteristic impedance of the electric line, said first coupler means comprising linear phase means for communicating the modulated carrier signal to the electric line without significant phase distortion and capacitor means for resonating with the linear phase means at the first preselected frequency;

receiver means having an output impedance for receiving the modulated carrier signal;

demodulator means electrically connected to said receiver means for demodulating said modulated carrier signal to produce a demodulated carrier signal having a second preselected frequency; and

second coupler means adapted to be connected between the electric line and the receiver means for matching the input impedance of said receiver means to the characteristic impedance of the electric line, said second coupler means comprising linear phase means for communicating the modulated carrier signal to the receiver means without significant phase distortion and capacitor means for resonating with the linear phase means at the second preselected frequency,

said linear means of said first and second means comprising an air core transformer; and

said air core transformer comprising;

a primary coil having a first diameter; and

a secondary coil having a second smaller diameter, said secondary coil extending coaxially within said primary coil such that an air gap is created between said primary and said secondary coils; and

capacitor means connected between said primary coil and said electric line, wherein said primary coil and said capacitor means are matched to the characteristic impedance of said electric line at a preselected bandwidth.