Through-the-earth communication system

• US 7,050,831 B2
• Filed: 01/11/2002
• Issued: 05/23/2006
• Est. Priority Date: 05/25/1999
• Status: Expired due to Fees

• Current Assignee: Transtek, Inc.
• Original Assignee: Transtek, Inc.
• Inventors: Meiksin, Zvi H., Kilgore, Robert J., Petrus, T. Brad
• Primary Examiner(s): Urban, Edward
• Assistant Examiner(s): Nguyen, Thuan T
• Application Number:
  US10/043,902
• Publication Number:
  US 20020098868A1
• Time in Patent Office: 1,593 Days
• Field of Search: 455/560, 455/567, 455/561, 455/554, 455/40, 455/3.05, 455/414.1, 455/130, 455/151.2, 455/269, 455/41.1, 455/47, 455/39, 455/41.2, 455/41.3, 455/43, 455/502, 455/507, 455/522, 455/203, 455/245.1, 455/250.1
• US Class Current: 455/560
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and system for communication within an energy-transmission-limited environment. RF transceivers throughout the site are located site-wide such that areas within the site in which communications are desired are within range of at least one of the RF transceivers. At each location RF transceivers are connected to a control unit. The control unit provides power to the transceivers and allows bi-directional communication of audio/voice and/or digital information. The control units may be networked to each other using standard network type category-5 or equivalent cables and may communicate to one another via the network connection. The control units may also be networked via an alternating current powerline by using an alternating current modem. The transceiver of the present invention utilizes single sideband modulators to modulate voice and/or digital signals. The signals are demodulated and filtered at a receiving end of the transceiver. A comb filter attenuates noisy signals with drifting harmonics.

Claims

1. A communication system for communicating between the surface and underground areas of the earth where amount of energy used for communications is limited, comprising:

a modulator for modulating a single sideband carrier signal;

a first amplifier coupled to the modulator to amplifier signals received from the modulator;

an antenna coupled to the first amplifier to receive amplified signals from the first amplifier, the antenna being tuned to receive or transmit or receive and transmit low signal levels, the antenna being coupled to a second antenna by Faraday coupling for communicating to a second system that includes the second antenna, wherein low energy input into the antenna is communicated to the second system via the second antenna;

a microprocessor operable at least to filter noise spike from received signals using half-wave averaging and median filtering;

a comb filter module coupled to the microprocessor, the comb filter module operable to attenuate one or more harmonics that induce noise in the received signals;

a demodulator coupled to the comb filter, the demodulator operable to recover signals; and

a switch operable to couple and decouple the antenna from a receiving terminal and a transmitting terminal,

wherein through-the-earth communication is enabled.

2. The communication system as claimed in claim 1, further including:

a second amplifier coupled to the single sideband modulator,

wherein the second amplifier receives signals representing voice input and transmits the signals to the single sideband modulator.

3. The communication system as claimed in claim 2, wherein the second amplifier includes an automatic gain control amplifier.

4. The communication system as claimed in claim 2, wherein the second amplifier includes an analog gain control amplifier.

5. The communicating system as claimed in claim 2, wherein the second amplifier includes a digital gain controller.

6. The communication system as claimed in claim 1, wherein the modulator includes a digital signal processor.

7. The communication system as claimed in claim 1, wherein the first amplifier includes:

a preamplifier to receive signal from the single sideband modulator; and

a power bridge amplifier coupled to the preamplifier and the antenna, wherein the power bridge amplifier receives the signal amplified by the preamplifier and applies the signal to the antenna with current.

8. The communication system as claimed in claim 1, wherein the modulator includes a frequency-shift-keying modulator.

9. The communication system as claimed in claim 1, wherein the modulator includes a phase-shift-keying modulator.

10. The communication system as claimed in claim 1, wherein the modulator includes a quadrature phase-shift-keying modulator.

11. The communication system as claimed in claim 1, further including a filter coupled to the microprocessor modulator, wherein the signal is filtered to be within a predetermined range.

12. The communication system as claimed in claim 11, wherein the filter is a passive filter.

13. The communication system as claimed in claim 12, further including an active filter coupled to the passive filter.

14. The communication system as claimed in claim 1, wherein the comb filter module includes a tracking comb filter coupled to the modulator, the tracking comb filter enabled to track drifting noise of selected frequency and their harmonics.

15. The communication system as claimed in claim 1, further including a relay coupled to the antenna, the rely enabled to connect and disconnect the antenna from coupling with a receiving terminal and a transmitting terminal.

16. The communication system as claimed in claim 15, wherein the switch is coupled to the relay to control the relay.

17. The communication system as claimed in claim 1, further including a relay coupled to the antenna, the relay enabled to connect and disconnect the antenna from coupling with the first amplifier.

18. The communication system of claim 1 wherein the antenna is tuned with a series capacitor to reduce impedance.

19. The communication system of claim 1, wherein power input into the antenna is kept low.

20. A through-the-earth communication system for communicating between the surface and underground areas of the earth where amount of energy used for communications is limited, comprising:

a transmitting unit comprising at least;

a first microprocessor for at least modulating signals;

a first amplifier coupled to the modulator to amplify the signals received from the modulator; and

a first loop antenna coupled to the first amplifier and being tuned to low frequencies and enabled to transmit the signals to a receiving antenna by Faraday coupling;

a receiving unit comprising at least;

a second loop antenna operable to receive signals by Faraday coupling;

a second microprocessor coupled to the second loop antenna operable to filter received signals using half-wave averaging and median filtering for removing noise spike in the received signals,

a comb filter module coupled to the second microprocessor, the comb filter module operable to track and attenuate one or more harmonics that induce noise in the received signals; and

a demodulator coupled to the comb filter, the demodulator operable to recover signal; and

a switch operable to couple and decouple the first and second antennas from the receiving unit and the transmitting unit.

21. The system of claim 20, wherein the first microprocessor includes a single side band modulator.

22. The system of claim 20, wherein the comb filter module includes tracking comb filter.

23. A through-the-earth communication system for communicating between the surface and underground areas of the earth where amount of energy used for communications is limited, comprising:

a transmitting unit comprising at least;

a first microprocessor for at least modulating signals;

a first amplifier coupled to the modulator to amplify the signals received from the modulator; and

a first loop antenna coupled to the first amplifier and being tuned to low frequencies and enabled to transmit the signals to a receiving antenna by Faraday coupling;

a receiving unit comprising at least;

a second microprocessor coupled to the second loop antenna operable to filter received signals using half-wave averaging and median filtering for removing noise spike in the received signals,

a comb filter module coupled to the second microprocessor, the comb filter module operable to attenuate one or more harmonics that induce noise in the received signals; and

a demodulator coupled to the comb filter, the demodulator operable to recover signals;

a loop antenna coupled to the first amplifier and being tuned to low frequencies and enabled to transmit the signals to a receiving antenna by Faraday coupling, the loop antenna further operable to receive signals by Faraday coupling; and

a switch operable to couple and decouple the loop antenna from the receiving unit and the transmitting unit.

24. The system of claim 23, wherein the first microprocessor includes a single side band modulator.

25. The system of claim 23, wherein the comb filter module includes tracking comb filter.

26. A method of communicating through-the-earth where amount of energy used for communications is limited, comprising:

receiving low frequency single side band signals via the loop antenna using Faraday coupling;

applying the low frequency single side band signals to a filter and removing noise;

limiting voltage of the noise filtered low frequency single side band signals;

attenuating harmonics in the low frequency single side band signals for allowing signals to be detected;

half-wave averaging and median filtering the low frequency single side band signals; and

demodulating the low frequency single side band signals to recover signals.

27. A communication system for communicating between the surface and underground areas of the earth where amount of energy used for communications is limited, comprising:

a modulator for modulating a single sideband carrier signal;

a first amplifier coupled to the modulator to amplify signals received from the modulator;

an antenna coupled to the first amplifier to receive amplified signals from the first amplifier, the antenna being tuned to receive or transmit or receive and transmit low signal levels, the antenna being coupled to a second antenna by Faraday coupling for communicating to a second system that includes the second antenna wherein low energy input into the antenna is communicated to the second system via the second antenna;

a microprocessor operable at least to filter noise spike from received signals;

a comb filter module coupled to the microprocessor, the comb filter module operable to attenuate one or more harmonics that induce noise in the received signals;

a demodulator coupled to the comb filter, the demodulator operable to recover signals;

a switch operable to couple and decouple the antenna from a receiving terminal and a transmitting terminal,

wherein through-the-earth communication is enabled.