Diversity circuit for magnetic communication system

Abstract

A magnetic communication system includes a transmitter have a single coil transducer, and a receiver having a three orthogonally oriented coil transducers. The signal processing circuitry in the receiver adjusts the phases of the signals received by the three transducers to produce signals which are in-phase. The signals are then summed to provide an output signal from the receiver. The processing circuitry adjusts the phases of the incoming signals either serially or in parallel. Transmissions from the receiver to the transmitter are also phase adjusted in accordance with the same adjustments used in reception.

1. A magnetic inductance communications system, comprising:
 a first transmission/reception coil producing a magnetic field including a transmitted signal;  
 a plurality of second transmission/reception coils having different orientations for receiving the transmitted signal and generating a plurality of received signals;  
 a summing circuit for combining the plurality of received signals to produce a summed signal;  
 at least one first phase adjusting circuit for adjusting a phase of at least one respective received signal prior to summing to increase the amplitude of the summed signal; and  
 a modulator circuit for modulating a signal to be transmitted, wherein the modulator circuit includes: 
 at least one second phase adjusting circuit receiving a carrier signal and a phase adjustment signal from the at least one first phase adjusting circuit;  
 a plurality of driving circuits, each driving circuit receiving the signal to be transmitted and a respective output signal from one of the second phase adjusting circuits, for generating a respective driving signal on one of the plurality of second transmission/reception coils to generate a second magnetic field; and  
 signal processing circuitry connected to the first transmission/reception coil to receive the signal in the second magnetic field.  
 
 
     
     
       2. The magnetic inductance communication system of  claim 1 , wherein said at least one second phase adjusting circuit changes polarity of the carrier signal based upon a polarity of at least one of the received signals. 
     
     
       3. The magnetic inductance communication system of  claim 1 , wherein said at least one second phase adjusting circuit adjusts the phase of the carrier signal according to phases of each of the received signals. 
     
     
       4. A magnetic inductance communication system comprising:
 a first transmission/reception coil producing a magnetic field including a transmitted signal;  
 a plurality of second transmission/reception coils having different orientations for receiving the transmitted signal and generating a plurality of received signals;  
 a plurality of amplitude determining circuits corresponding to the plurality of second transmission/reception coils for determining amplitudes of the plurality of received signals;  
 a modulator circuit for modulating a signal to be transmitted, wherein the modulator circuit includes: 
 a plurality of driving circuits each driving circuit receiving a carrier signal to be transmitted for generating a respective driving signal on one of the plurality of transmission/reception coils to generate a second magnetic field; and  
 a selection circuit for activating at least one of the driving circuits based upon the amplitudes of the received signals; and  
 signal processing circuitry connected to the first transmission/reception coil to receive the signal in the second magnetic field.  
 
 
     
     
       5. The magnetic inductance communication system of  claim 4 , wherein the selection circuit activates one of the driving circuits corresponding to a transmission/reception coil having a greatest amplitude of a received signal. 
     
     
       6. The magnetic inductance communication system of  claim 4 , wherein the selection circuit activates two of the driving circuits corresponding to a transmission/reception coils having a greatest amplitudes of received signals. 
     
     
       7. The magnetic inductance communication system of  claim 6 , wherein the modulator further includes at least one phase adjusting circuit receiving the carrier signal and a phase adjustment signal for adjusting phase of the carrier signal provided to at least one of the two activated driving circuits so that the combined second magnetic field has a maximum value. 
     
     
       8. A method for communicating, the method comprising the steps of:
   receiving an inductive input signal on each of multiple uniquely oriented transducers;        generating an electronic signal corresponding to the received inductive input signal for each of the transducers;        compensating for a relative motion of the transducers with respect to the inductive input signal by adjusting a phase of at least one of the electronic signals; and        summing the aligned electronic signals to produce an output signal that corresponds to the inductive input signal.     
     
     
       9. A method as in  claim 8  further comprising:
   multiplexing each of the electronic signals to an error amplifier circuit and generating corresponding phase adjustment signals to align the electronic signals.     
     
     
       10. A method as in  claim 9  further comprising:
   maintaining a phase adjustment of at least one electronic signal during which another electronic signal is monitored for generating a corresponding phase adjustment signal.     
     
     
       11. A method as in  claim 8 , wherein the transducers are inductive transducer devices. 
     
     
       12. A method as in  claim 8  further comprising:
   adjusting a polarity of one or more of the electronic signals so that the electronic signals have the same sign and sum to produce a larger output signal.     
     
     
       13. A method as in  claim 12 , wherein a polarity of an electronic signal corresponding to the inductive input signal is changed by phase shifting. 
     
     
       14. A method as in  claim 8 , wherein the inductive input signal includes information modulated on a carrier frequency signal. 
     
     
       15. A method as in  claim 8 , wherein the uniquely oriented transducers are orthogonally disposed to each other. 
     
     
       16. A method as in  claim 8  further comprising:
   comparing a phase of each of the electronic signals with a common reference signal; and        controlling a local oscillator in a corresponding phase shifter to align the phase of each electronic signal with the reference signal.     
     
     
       17. A method as in  claim 8  further comprising:
   generating an error signal that is used to adjust a phase of at least one electronic signal relative to a reference signal.     
     
     
       18. A method as in  claim 8 , wherein the phase of the electronic signals are adjusted at a fast enough rate to account for the relative motion of the transducers. 
     
     
       19. A method as in  claim 8  wherein adjusting the phase of at least one of the electronic signals substantially aligns the electronic signals with each other. 
     
     
       20. A method for communicating, the method comprising the steps of:
   orienting each of multiple transducers along a unique axis to generate a magnetic field;        identifying a target receiver to which the magnetic field is transmitted; and        adjusting a phase output of the multiple transducers to produce the magnetic field for the target receiver.     
     
     
       21. A method as in  claim 20 , wherein the magnetic field is generated from three orthogonally disposed transducers. 
     
     
       22. A method as in  claim 20  further comprising:
   receiving the magnetic field on a single reception coil at the target receiver.     
     
     
       23. A method as in  claim 22 , wherein the single reception coil is disposed in a portable device. 
     
     
       24. A method as in  claim 20  further comprising:
   generating an electronic signal of information to be transmitted to the target receiver; and        multiplying the electronic signal with corresponding phase adjusted carrier frequencies to produce modulated signals and driving the transducers with the modulated signals to produce the magnetic field.     
     
     
       25. A method as in  claim 20  further comprising:
   disposing the multiple transducers in a portable device.     
     
     
       26. A method as in  claim 25  further comprising:
   coupling the portable device to a communications network.     
     
     
       27. A method for communicating, the method comprising the steps of:
   receiving an inductive input signal on each of multiple uniquely oriented receiver transducers, the inductive input signal being received from a remote source transducer;        generating an electronic signal from each of the receiver transducers, each electronic signal corresponding to the inductive input signal;        based on a phase difference of the electronic signals, adjusting a phase of at least one of multiple transmitter transducers to produce an inductive output signal that is transmitted to a target receiver transducer near the remote source transducer.     
     
     
       28. A method as in  claim 27 , wherein the multiple transmitter transducers are aligned along similar axes as the uniquely oriented receiver transducers. 
     
     
       29. A method as in  claim 28 , wherein the uniquely oriented receiver transducers and the transmitter transducers to transmit and receive corresponding inductive signals are the same transducers. 
     
     
       30. A method as in  claim 27 , wherein the target receiver transducer near the remote source transducer is oriented along a same axis as the remote source transducer. 
     
     
       31. A method as in  claim 27 , wherein the target receiver transducer and the remote source transducer are a single transducer that is used to both transmit and receive corresponding inductive signals. 
     
     
       32. A method as in  claim 27 , wherein the inductive output signal is transmitted to a portable device. 
     
     
       33. A method as in  claim 32 , wherein the portable device is coupled to a communications network. 
     
     
       34. A method as in  claim 27 , wherein the receiver transducers are three orthogonally positioned transducers. 
     
     
       35. A method as in  claim 27 , wherein the inductive input signal is received from a portable headset. 
     
     
       36. A method as in  claim 27  further comprising:
   multiplexing each of the electronic signals to an error amplifier circuit and generating corresponding phase adjustment signals to align the electronic signals; and        utilizing the phase adjustment signals to produce the inductive output signal.     
     
     
       37. A method as in  claim 36  further comprising:
   maintaining a phase adjustment of at least one transmitter transducer during which another electronic signal is monitored for generating a corresponding phase adjustment signal for another transmitter transducer.     
     
     
       38. A method as in  claim 27 , wherein the inductive output signal includes information modulated on a carrier frequency signal. 
     
     
       39. A method as in  claim 27 , wherein the uniquely oriented receiver transducers are orthogonally disposed to each other. 
     
     
       40. A method as in  claim 27  further comprising:
   comparing a phase of each of the electronic signals with a common reference signal; and        controlling a local oscillator in a corresponding phase shifter to adjust the phase of each transmitter transducer with respect to the reference signal.     
     
     
       41. A method as in  claim 27  wherein:
   adjusting a phase of at least one of the multiple transmitter transducers compensates for a relative motion of the receiver transducers with respect to the inductive input signal.     
     
     
       42. A method for communicating, the method comprising the steps of:
   receiving an inductive input signal on each of multiple uniquely oriented receiver transducers, the inductive input signal being generated from a remote source transducer;        producing an electronic signal that corresponds to the inductive input signal for each of the receiver transducers, a level of each electronic signal being proportional to a strength of the received inductive input signal at a corresponding receiver transducer;        tracking a phase of each electronic signal during motion of the remote source transducer relative to the multiple uniquely oriented receiver transducers; and        based on the phase of at least one electronic signal, adjusting an inductive output signal from a transmitter transducer for communicating with a target receiver.     
     
     
       43. A method as in  claim 42 , wherein the transmitter transducer from which the inductive output signal is generated is one of multiple uniquely oriented transmitter transducers. 
     
     
       44. A method as in  claim 43 , wherein the uniquely oriented transmitter transducers generating an inductive output signal are aligned along similar axes as the uniquely oriented receiver transducers receiving the inductive input signal. 
     
     
       45. A method as in  claim 44 , wherein the transducers to transmit and receive corresponding inductive signals are the same multiple uniquely oriented transducers. 
     
     
       46. A method as in  claim 43  further comprising:
   detecting which of the multiple receiver transducers produces a strongest set of electronic signals; and        generating an inductive output signal from transmitter transducers oriented on similar axes as the receiver transducers that generate the strongest set of electronic signals.     
     
     
       47. A method as in  claim 46  further comprising:
   adjusting at least one phase output of the transmitter transducers generating the inductive output signal for maximal reception at a target receiver transducer located near the remote source transducer.     
     
     
       48. A method as in  claim 42  further comprising:
   comparing an amplitude of the electronic signals to determine which of the multiple uniquely oriented receiver transducers receives the strongest electronic signal.     
     
     
       49. A method as in  claim 42 , wherein the inductive output signal is transmitted to the target receiver transducer near the remote source transducer. 
     
     
       50. A method as in  claim 49 , wherein the target receiver transducer near the remote source transducer is oriented along a similar axis as the remote source transducer. 
     
     
       51. A method as in  claim 42 , wherein the target receiver transducer and the remote source transducer are a single transducer that is used to both transmit and receive corresponding inductive signals. 
     
     
       52. A method as in  claim 42 , wherein the inductive output signal is transmitted to a portable device. 
     
     
       53. A method as in  claim 52 , wherein the portable device is coupled to a communications network. 
     
     
       54. A system for communicating, the system comprising:
   multiple uniquely oriented receiver transducers, each of which receives an inductive input signal, the inductive input signal being generated from a remote source transducer;        a circuit coupled to the receiver transducers that produces an electronic signal corresponding to the inductive input signal for each of the receiver transducers, the phase of each electronic signal being a function of the position and orientation of the remote source relative to the multiple uniquely oriented receiver transducers;        a detection circuit that detects the phase of each electronic signal based upon a reception of the inductive input signal; and        a driver circuit that generates an inductive output signal from a based on the phase of at least one of the produced electronic signals.     
     
     
       55. A system as in  claim 54 , wherein the transmitter transducer from which the inductive output signal is generated is one of multiple uniquely oriented transmitter transducers. 
     
     
       56. A system as in  claim 55 , wherein the uniquely oriented transmitter transducers are aligned along similar axes as the uniquely oriented receiver transducers receiving the inductive input signals. 
     
     
       57. A system as in  claim 56 , wherein the transducers to transmit and receive corresponding inductive signals are the same uniquely oriented transducers. 
     
     
       58. A system as in  claim 55  further comprising:
   a detection circuit that detects which of the multiple receiver transducers produces a strongest set of electronic signals; and        driver circuits to generate an inductive output signal from at least one of the transmitter transducers oriented on similar axes as the receiver transducers that generate the strongest set of electronic signals.     
     
     
       59. A system as in  claim 58 , wherein at least one phase output of the transmitter transducers is adjusted to generate the inductive output signal for maximal reception at a target receiver transducer located near the remote source transducer. 
     
     
       60. A system as in  claim 54 , wherein the detection circuit compares an amplitude of each of the produced electronic signals to determine which of multiple uniquely oriented transmitter transducers will generate the inductive output signal. 
     
     
       61. A system as in  claim 60 , wherein the inductive output signal is transmitted to a target receiver transducer near the remote source transducer. 
     
     
       62. A system as in  claim 60 , wherein the target receiver transducer near the remote source transducer is oriented along a similar axis as the remote source transducer. 
     
     
       63. A system as in  claim 62 , wherein the target receiver transducer and the remote source transducer are a single transducer that is used to both transmit and receive corresponding inductive signals. 
     
     
       64. A system as in  claim 54 , wherein the inductive output signal is transmitted to a portable device. 
     
     
       65. A system as in  claim 64 , wherein the portable is coupled to a communications network.