INDUCTIVELY COUPLED DATA COMMUNICATION APPARATUS

• US 3,742,150 A
• Filed: 04/28/1971
• Issued: 06/26/1973
• Est. Priority Date: 04/28/1971
• Status: Expired due to Term

• Current Assignee: Leigh E. Sherman, Lynn D. Crawford, Walter P. Adams
• Original Assignee: Leigh E. Sherman, Lynn D. Crawford, Walter P. Adams
• Inventors: Sherman, Leigh E., Adams, Walter P., Crawford, Lynn D.
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): Stewart, David L.
• Application Number:
  US05/138,194
• Time in Patent Office: 790 Days
• Field of Search: 179/82,1VE 340/51,149A,195,174.1A,26 164/88 246/63C,2E
• US Class Current: 455/41.1
• CPC Class Codes: H04B 5/263 Multiple coils at either side

Abstract

Data communication apparatus utilizing a current source, a first set of closely adjacent transmitting coils energized by that current source for developing a first series of magnetic fields and second set of closely adjacent transmitting coils energized by that current source for developing a second series of magnetic fields which have a particular relationship to the first series of magnetic fields, commensurate with the data to be communicated. Carried by a vehicle passing over the transmitting coils is a magnetic field sensing means for each set of coils each of which develops an output signal for comparison with one another when the sensing means is at a preselected position with respect to each transmitting coil.

Claims

1. Data communication apparatus, comprising:

a current source;

a first set of transmitting coils energized by said source and operative to develop a first series of magnetic fields;

a second set of transmitting coils energized by said source and operative to develop a second series of magnetic fields having a predetermined relationship to said first series of magnetic fields, said relationship being indicative of the data to be communicated;

magnetic field sensing means including, a first receiving coil disposed for passage through said first series of magnetic fields and operative to develop first signals, and a second receiving coil disposed for passage through said second series of magnetic fields and operative to develop second signals;

signal comparing means responsive to sAid first and second signals and operative to develop output signals, commensurate with the data to be communicated; and

gating means responsive to said first signal for allowing said output signal to pass to an output line when said first receiving coil is at preselected positions with respect to each transmitting coil of said first set.

2. Data communication apparatus as recited in claim 1 wherein said first set of transmitting coils includes a continuous conductor distributed over a first tortuous path to provide a first series of loops each forming one of the transmitting coils of said first set.

3. Data communication apparatus as recited in claim 2 wherein said first tortuous path lies within a single plane and each of said transmitting coils in said first set develops a magnetic field oppositely polarized with respect to that developed by the immediately adjacent transmitting coils in said first set.

4. Data communication apparatus as recited in claim 2 wherein said second set of transmitting coils includes an extension of said continuous conductor distributed over a second tortuous path to provide a second series of loops each forming one of the transmitting coils of said second set and each having a predetermined relationship to one or more of the coils of said first set.

5. Data communication apparatus as recited in claim 4 wherein said first and second tortuous paths lie within a single plane and each of the transmitting coils of said second set are disposed laterally adjacent portions of said plane in common with one or more of the transmitting coils of said first set.

6. Data communication apparatus as recited in claim 5 wherein the transmitting coils of said first set are disposed along a straight line lying in said plane and the transmitting coils of said second set are disposed along a second line parallel to said first line and lying in said plane, said particular portions being generally rectangular and including said first and seconds lines.

7. Data communication apparatus as recited in claim 1 and further comprising:

a third set of transmitting coils energized by said source and operative to develop a third series of magnetic fields;

switching means for coupling the coils of said third set to said source in either one configuration whereby the instantaneous current through the various coils is in one direction or in an opposite configuration whereby the instantaneous current through the various coils is in the opposite direction;

said sensing means further including a third receiver coil disposed for passage through said third series of magnetic fields and operative to develop third signals, said signal comparing means being additionally responsive to said third signals.

8. Data communication apparatus, comprising:

a source of alternating current;

a first set of closely adjacent transmitting coils energized by said source and operative to develop a first series of magnetic fields;

a second set of transmitting coils coextensive with said first set of coils energized by said source and operative to develop a seconds series of magnetic fields having a predetermined relationship to said first series indicative of the data to be communicated;

first and second magnetic field detectors disposed for movement through said first and second set of coils, respectively; and

means for comparing the signals developed in said first and second detectors and for providing an output signal only when said first detector is at a preselected position with respect to each coil of said first set.

9. Data communication apparatus as recited in claim 8 wherein said first set of transmitting coils includes a first segment of a continuous conductor distributed over a first tortuous path to provide a first series of loops each forming one of the transmitting coils of said first set.

10. Data communication apparatus as recited in claim 9 wherein said first tortuous path lies within a single plane and each of the traNsmitting coils in said first set develops a magnetic field oppositely polarized with respect to that developed by the immediately adjacent transmitting coils in said first set.

11. Data communication apparatus as recited in claim 9 wherein said second set of transmitting coils includes a second segment of said continuous conductor distributed over a second tortuous path to provide a second series of loops each forming one of the transmitting coils of said second set.

12. Data communication apparatus as recited in claim 11 wherein said first and second tortuous paths lie within a single plane and each of the transmitting coils of said second set are disposed laterally adjacent particular portions of said plane, said portions including one of the transmitting coils of said second set and one or more of the transmitting coils of said first set.

13. Data communication apparatus comprising:

magnetic field sensing means including, a first receiver coil having a first sensitive axis, a second receiver coil having a second sensitive axis disposed at an angle relative to said first sensitive axis, said first and second receiver coils being responsive to a first magnetic field and operative to develop first and second signals respectively, and a third receiver coil responsive to a second magnetic field and operative to develop third signals;

a first phase comparator responsive to said first and second signals and operative to develop clock signals;

a second phase comparator responsive to said first and third signals and operative to develop data signals; and

a shift register responsive to said clock signals and said data signals and operative to develop output signals.

14. Data communication apparatus, comprising:

a current source;

a first set of transmitting coils energized by said source and operative to develop a first series of magnetic fields;

a second set of transmitting coils energized by said source and operative to develop a second series of magnetic fields having a predetermined relationship to said first series of magnetic fields, said relationship being indicative of the data to be communicated;

magnetic field sensing means including, a first receiving coil disposed for passage through said first series of magnetic fields and operative to develop first signals, a second receiving coil disposed for passage through said second series of magnetic fields and operative to develop second signals, and a third receiving coil disposed for passage through said first series of magnetic fields and operative to develop third signals, said third receiving coil having a sensitivity axis angularly disposed relative to the sensitivity axis of said first receiving coil; and

signal comparing means responsive to said first and second signals and operative to develop output signals commensurate with said data to be communicated, said signal comparing means also including gating means responsive to said third signals for gating said output signals to an output line.

15. Data communication apparatus as recited in claim 14 wherein said signal comparing means includes, a first phase comparator responsive to said first and third signals and operative to develop clock signals, a second phase comparator responsive to said first and second signals and operative to develop data signals, and a shift register responsive to said clock signals and said data signals and operative to provide said output signals.