Through-the-earth radio

• US 7,043,204 B2
• Filed: 11/20/2003
• Issued: 05/09/2006
• Est. Priority Date: 06/26/2003
• Status: Expired due to Fees

• Current Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Reagor, David, Vasquez-Dominguez, Jose
• Primary Examiner(s): LE, DANH C
• Application Number:
  US10/719,426
• Publication Number:
  US 20040266497A1
• Time in Patent Office: 901 Days
• Field of Search: 455/40, 455/41.3, 455/131, 375/295, 375/219, 340/854.6
• US Class Current: 455/40
• CPC Class Codes: H04B 13/02 Transmission systems in which the medium consists of the earth or a large mass of water thereon, e.g. earth telegraphy

Abstract

A method and apparatus for effective through-the-earth communication involves a signal input device connected to a transmitter operating at a predetermined frequency sufficiently low to effectively penetrate useful distances through-the earth, and having an analog to digital converter receiving the signal input and passing the signal input to a data compression circuit that is connected to an encoding processor, the encoding processor output being provided to a digital to analog converter. An amplifier receives the analog output from the digital to analog converter for amplifying said analog output and outputting said analog output to an antenna. A receiver having an antenna receives the analog output passes the analog signal to a band pass filter whose output is connected to an analog to digital converter that provides a digital signal to a decoding processor whose output is connected to an data decompressor, the data decompressor providing a decompressed digital signal to a digital to analog converter. An audio output device receives the analog output form the digital to analog converter for producing audible output.

Claims

1. A through-the-earth communication system comprising:

an audio signal input device;

a transmitter operating at a predetermined frequency sufficiently low to effectively penetrate useful distances through-the earth, and having an analog to digital converter receiving said audio signal input and passing said audio signal input to a data compression circuit whose output is connected to an encoding processor, said encoding processor output being provided to a digital to analog converter;

an amplifier receiving analog output from said digital to analog converter for amplifying said analog output and outputting said analog output to an antenna;

a receiver having an antenna receiving said analog output and passing said analog output to a band pass filter being connected to an analog to digital converter that provides a digital signal to a decoding processor whose output is connected to an data decompressor, said data decompressor providing a decompressed digital signal to a digital to analog converter; and

an audio output device receiving analog output form said digital to analog converter for producing audible output.

2. The apparatus as described in claim 1 wherein said audio signal input device is a microphone.

3. The apparatus as described in claim 1 wherein said antenna is a loop antenna.

4. The apparatus as described in claim 1, wherein said encoding processor operates using quadrature phase shift keying.

5. The apparatus as described in claim 1, wherein said encoding processor operates using a QAM-16 processor.

6. The apparatus as described in claim 1, wherein said predetermined frequency is approximately 7 kHz.

7. The apparatus as described in claim 1, wherein said predetermined frequency is approximately 4 kHz.

8. The apparatus as described in claim 1, wherein said band pass filter is of the wideband 4-pole elliptic design.

9. The apparatus as described in claim 1, wherein said antenna is a SQUID detector connected to a flux locked loop.