Communication system

• US 6,271,790 B2
• Filed: 04/23/1998
• Issued: 08/07/2001
• Est. Priority Date: 05/09/1997
• Status: Expired due to Term

• Current Assignee: Olive Branch Holdings, LLC, Smith Technology Development, LLC
• Original Assignee: Smith Technology Development, LLC
• Inventors: Smith, Stephen H.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/064,525
• Publication Number:
  US 20010003442A1
• Time in Patent Office: 1,202 Days
• Field of Search: 342/361, 342/362, 342/363, 342/364, 342/365, 342/366
• US Class Current: 342/365
• CPC Class Codes: H04B 10/532 Polarisation modulation
• CPC Class Codes: H04B 14/008 Polarisation modulation
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

A communications system in which a communications channel is defined at least in part by an electromagnetic wave having a carrier frequency and an electric field vector, the extremity or terminus of which traces a non-linear periodic path at a rotation frequency less than the carrier frequency and greater than zero from the perspective of an observer looking into the axis of propagation of the wave. The transmitter of the communications system launches a wave having such characteristics and modulated with information in a suitable manner. The receiver of the communications system is sensitive to the periodic path and rotation frequency. The combination of the periodic path and the carrier frequency provides selectivity that can be used to define multiple communications channels.

Claims

1. A method for transmitting information using an electromagnetic wave, establishing at least a first information channel and a second information channel, each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination, at least one information channel being established by:

modulating a carrier signal having the carrier frequency associated with the one information channel with information to produce a plurality of modulated component signals; and

modulating each modulated component signal with one rotation signal from a plurality of rotation signals, each rotation signal from the plurality of rotation signals having the rotation frequency associated with the one information channel, the rotation frequency being between the associated carrier frequency and zero, each rotation signal being phase shifted from the remaining rotation signals;

multiplexing the at least two information channels; and

transmitting an electromagnetic wave having the multiplexed at least two information channels, the electromagnetic wave having a plurality of wave components, each wave component being associated with one information channel and each wave component having an electric field rotating about a propagation axis at the associated rotation frequency.

2. The method of claim 1, wherein, for the one information channel, the carrier signal is amplitude modulated with the information.

3. The method of claim 1, wherein, for the one information channel, the carrier signal is phase modulated with the information.

4. The method of claim 1, wherein, for the one information channel, the carrier signal is frequency modulated with the information.

66. The method of claim 1, wherein a frequency of the rotating polarization of each wave component is different from that of any other wave component.

5. A method for transmitting information using an electromagnetic wave, comprising:

establishing at least a first information channel and a second information channel, each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination, at least one information channel being established by;

modulating each rotation signal from a plurality of rotation signals with information to produce a plurality of modulated rotation signals, each rotation signal from the plurality of rotation signals having the rotation frequency associated with the one information channel, each rotation signal being phase shifted from the remaining rotation signals; and

modulating each modulated rotation signal with a carrier signal having the carrier frequency associated with the one information channel;

multiplexing the at least two information channels; and

transmitting an electromagnetic wave having the multiplexed at least two information channels, the electromagnetic wave having a plurality of wave components, each wave component being associated with one information channel and each wave component having an electric field rotating about a propagation axis at the associated rotation frequency.

6. The method of claim 5, wherein, for the one information channel, each modulated rotation signal is amplitude modulated with the information.

7. A method for transmitting information using an electromagnetic wave, comprising:

establishing at least a first information channel and a second information channel, each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination, at least one information channel being established by;

modulating each rotation signal from a plurality of rotation signals with one component signal from a plurality of component signals to produce a plurality of modulated carrier signals, each rotation signal from the plurality of rotation signals having the rotation frequency associated with the one information channel, each component signal from the plurality of component signals having the carrier frequency associated with the one information channel, each rotation signal being phase shifted from the remaining rotation signals; and

modulating each modulated carrier signal with information;

multiplexing the at least two information channels; and

transmitting an electromagnetic wave having the multiplexed at least two information channels, the electromagnetic wave having a plurality of wave components, each wave component being associated with one information channel and each wave component having an electric field rotating about a propagation axis at the associated rotation frequency.

8. The method of claim 7, wherein, for the one information channel, each modulated carrier signal is amplitude modulated with the information.

9. A method for transmitting information using an electromagnetic wave, comprising:

establishing at least a first information channel and a second information channel, each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination at least one information channel being established by;

generating a first component signal having a first carrier frequency;

generating a second component signal having a second carrier frequency different from the first component signal; and

modulating the first component signal and the second component signal with information,

the carrier frequency associated with the component of the transmitted electromagnetic wave associated with the one information channel being an average of the first carrier frequency and the second carrier frequency, and

the rotation frequency associated with the component of the transmitted electromagnetic wave associated with the one information channel being one half of the difference of the first carrier frequency and the second carrier frequency;

multiplexing the at two information channels; and

transmitting an electromagnetic wave having the multiplexed at least two information channels, the electromagnetic wave having a plurality of wave components each being associated with one information channel and each having an electric field rotating about a propagation axis at the associated rotation frequency.

10. The method of claim 9, wherein, for the one information channel, the first component signal and the second component signal are modulated with the information.

11. The method of claim 9, wherein, for the one information channel, the first component signal and the second component signal are amplitude modulated with the information.

12. The method of claim 9, wherein, for the one information channel, the first component signal and the second component signal are phase modulated with the information.

13. The method of claim 9, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are modulated with the information.

14. The method of claim 9, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are amplitude modulated with the information.

15. A method for receiving information using an electromagnetic wave, comprising:

receiving an electromagnetic wave having at least a first information channel and a second information channel multiplexed together each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination the electromagnetic wave having a plurality of wave components each being associated with one information channel and each having an electric field rotating about a propagation axis at the associated rotation frequency less than the associated carrier frequency and greater than zero;

demultiplexing the at least two information channels based on the plurality of received signals; and

reestablishing the at least two information channels, at least one information channel being reestablished by;

generating a plurality of received signals based on the wave component associated with the one information channel;

generating a plurality of rotation signals each having the rotation frequency associated with the one information channel, each rotation signal being phase shifted from the remaining rotation signals;

demodulating each received signal with one rotation signal from the plurality of rotation signals to produce a plurality of demodulated received signals;

summing the plurality of demodulated received signals to produce a sum signal; and

demodulating the sum signal with the carrier signal associated with the one information channel to recover the information.

16. The method of claim 15, wherein, for the one information channel, the sum signal is amplitude demodulated with the associated carrier signal to recover the information.

17. The method of claim 15, wherein, for the one information channel, the sum signal is phase demodulated with the associated carrier signal to recover the information.

18. A method for receiving information using an electromagnetic wave, comprising:

receiving an electromagnetic wave having at least a first information channel and a second information channel multiplexed together, each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination, the electromagnetic wave having a plurality of wave components each being associated with one information channel and each having an electric field rotating about a propagation axis at the associated rotation frequency less than the associated carrier frequency and greater than zero;

demultiplexing the at least two information channels based on the plurality of received signals; and

reestablishing the at least two information channels, at least one information channel being reestablished by;

generating a plurality of received signals based on the wave component associated with the one information channel;

demodulating each received signal with one component signal from a plurality of component signals to produce a plurality of demodulated received signals, each component signal from the plurality of component signals having the carrier frequency associated with the one information channel;

demodulating each demodulated received signal with one rotation signal from a plurality of rotation signals to produce a plurality of information signals, each rotation signal from the plurality of rotation signals having the rotation frequency associated with the one information channel, each rotation signal being phase shifted from the remaining rotation signals; and

summing the plurality of information signals to produce a sum information signal.

19. The method of claim 18, wherein, for the one information channel, the demodulated received signals are demodulated with the associated rotation signal to recover the information.

20. The method of claim 18, wherein, for the one information channel, the demodulated received signals are amplitude demodulated with the associated rotation signal to recover the information.

21. A method for receiving information using an electromagnetic wave, comprising:

receiving an electromagnetic wave having at least a first information channel and a second information channel, each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination, the electromagnetic wave having a plurality of wave components each being associated with one information channel and each having an electric field rotating about a propagation axis at the associated rotation frequency less than the associated carrier frequency and greater than zero;

demultiplexing the at least two information channels based on the plurality of received signals; and

reestablishing the at least two information channels, at least one information channel being reestablished by;

generating a first component signal having a first carrier frequency;

generating a second component signal having a second carrier frequency different from the first component signal; and

demodulating the first component signal and the second component signal to recover the information,

the rotation frequency associated with each component of the transmitted electromagnetic wave being an average of the first carrier frequency and the second carrier frequency.

22. The method of claim 21, wherein, for the one information channel, the first component signal and the second component signal are demodulated to recover the information.

23. The method of claim 21, wherein, for the one information channel, the first component signal and the second component signal are amplitude demodulated to recover the information.

24. The method of claim 21, wherein, for the one information channel, the first component signal and the second component signal are phase demodulated to recover the information.

25. The method of claim 21, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are demodulated to recover the information.

26. The method of claim 21, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are amplitude demodulated to recover the information.

27. An apparatus for transmitting information using an electromagnetic wave, comprising:

at least a first transmission system and a second transmission system each associated with an information channel, each transmission system from the at least two transmission systems being associated with a combination of a carrier frequency and a rotation frequency, the first transmission system combination being different from the second transmission system combination, the first transmission system includes;

a first modulator, said first modulator modulates a carrier signal with the information to produce a plurality of modulated component signals; and

a second modulator coupled to said first modulator, said second modulator phase shifting each rotation signal from the plurality of rotation signals, said second modulator modulating each modulated component signal from the plurality of modulated component signals with one rotation signal from the plurality of rotation signals; and

a transmission medium coupler connected to said at least two transmission systems, said transmission medium coupler multiplexing and transmitting the at least two information channels associated with the at least two transmission systems.

28. The apparatus of claim 27, wherein, for the one information channel, the carrier signal is amplitude modulated with the information.

29. The apparatus of claim 27, wherein, for the one information channel, the carrier signal is phase modulated with the information.

30. The apparatus of claim 27, wherein, for the one information channel, the carrier signal is frequency modulated with the information.

31. An apparatus for transmitting information using an electromagnetic wave, comprising:

at least a first transmission system and a second transmission system each associated with an information channel, each transmission system from the at least two transmission systems being associated with a combination of a carrier frequency and a rotation frequency, the first transmission system combination being different from the second transmission system combination, the first transmission system includes;

a first modulator, said first modulator phase shifting each rotation signal from a plurality of rotation signals, each rotation signal from the plurality of rotation signals having the rotation frequency associated with the first transmission system, said first modulator modulating each component signal from a plurality of component signals with one rotation signal from the plurality of rotation signals to produce a plurality of modulated component signals, each component signal from the plurality of component signals having the carrier frequency associated with the first transmission system; and

a second modulator coupled to said first modulator, said second modulator modulating each modulated component signal from the plurality of modulated component signals with the information; and

a transmission medium coupler connected to said at least two transmission systems, said transmission medium coupler multiplexing and transmitting the at least two information channels associated with the at least two transmission systems.

32. The apparatus of claim 31, wherein, for the one information channel, each modulated component signal is amplitude modulated with the information.

33. An apparatus for transmitting information using an electromagnetic wave, comprising:

at least a first transmission system and a second transmission system each associated with an information channel, each transmission system from the at least two transmission systems being associated with a combination of a carrier frequency and a rotation frequency, the first transmission system combination being different from the second transmission system combination, the first transmission system includes;

a first modulator, said first modulator phase shifting each rotation signal from a plurality of rotation signals having the rotation frequency associated with the transmission system, said first modulator modulating each rotation signal with the information to produce a plurality of modulated rotation signals; and

a second modulator coupled to said first modulator, said second modulator modulating each modulated rotation signal with a carrier signal having the carrier frequency associated with the transmission system; and

a transmission medium coupler connected to said at least two transmission systems, said transmission medium coupler multiplexing and transmitting the at least two information channels associated with the at least two transmission systems.

34. The apparatus of claim 33, wherein, for the one information channel, each modulated rotation signal is amplitude modulated with the information.

35. An apparatus for transmitting information using an electromagnetic wave, comprising:

at least a first transmission system and a second transmission system each associated with an information channel, each transmission system from the at least two transmission systems being associated with a combination of a carrier frequency and a rotation frequency, the first transmission system combination being different from the second transmission system combination, the first transmission system includes;

a first information modulator, said information modulator modulating a first component signal having a first carrier frequency; and

a second information modulator, said information modulator modulating a second component signal having a second carrier frequency with the information, the associated carrier frequency being an average of the first carrier frequency and the second carrier frequency, and

the associated rotation frequency being one half of the difference of the first carrier frequency and the second carrier frequency; and

a transmission medium coupler connected to said at least two transmission systems, said transmission medium coupler multiplexing and transmitting the at least two information channels associated with the at least two transmission systems.

36. The apparatus of claim 35, wherein, for the one information channel, the first component signal and the second component signal are modulated with the information.

37. The apparatus of claim 35, wherein, for the one information channel, the first component signal and the second component signal are amplitude modulated with the information.

38. The apparatus of claim 35, wherein, for the one information channel, the first component signal and the second component signal are phase modulated with the information.

39. The apparatus of claim 35, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are modulated with the information.

40. The apparatus of claim 35, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are amplitude modulated with the information.

41. An apparatus for receiving information using an electromagnetic wave, comprising:

a transmission medium decoupler, said transmission medium decoupler receiving the electromagnetic wave having at least two multiplexed information channels to produce a plurality of received signals; and

at least a first receiving system and a second receiving system coupled to said transmission medium decoupler, the at least two receiving systems each being associated with an information channel from the at least two multiplexed information channels, each receiving system from the at least two receiving systems being associated with a combination of a carrier frequency and a rotation frequency, the first receiving system combination being different from the second receiving system combination, a receiving system from the at least two receiving systems includes;

a first demodulator, said first demodulator phase shifting each rotation signal from a plurality of rotation signals having the associated rotation frequency, said first demodulator demodulating each received signal from the plurality of received signals with one rotation signal from the plurality of rotation signals to produce a plurality of demodulated received signals;

a summer coupled to the at least two receiving systems, said summer summing the plurality of demodulated received signals to produce a sum signal; and

a second demodulator coupled to said summer, said second demodulator demodulating the information from the sum signal with a carrier signal having a carrier frequency.

42. The apparatus of claim 41, wherein, for the one information channel, the sum signal is amplitude modulated with the information.

43. The apparatus of claim 41, wherein, for the one information channel, the sum signal is rotation modulated with the information.

44. The apparatus of claim 41, wherein, for the one information channel, the sum signal is phase modulated with the information.

45. An apparatus for receiving information using an electromagnetic wave, comprising:

a transmission medium decoupler, said transmission medium decoupler receiving the electromagnetic wave having at least two multiplexed information channels to produce a plurality of received signals; and

at least a first receiving system and a second receiving system coupled to said transmission medium decoupler, the at least two receiving systems each being associated with an information channel from the at least two multiplexed information channels, each receiving system from the at least two receiving systems being associated with a combination of a carrier frequency and a rotation frequency, the first receiving system combination being different from the second receiving system combination, a receiving system from the at least two receiving systems includes;

a first demodulator, said first demodulator demodulating each received signal with a carrier signal having a carrier frequency to produce a plurality of demodulated component signals; and

a second demodulator coupled to said first demodulator, said second demodulator phase shifting each rotation signal from a plurality of rotation signals having the associated rotation frequency, said second demodulator demodulating each demodulated component signal from the plurality of demodulated component signals with one rotation signal from the plurality of rotation signals to produce a plurality of demodulated rotation signals;

a summer coupled to the at least two receiving systems, said summer summing the plurality of demodulated rotation signals to produce the information.

46. The apparatus of claim 45, wherein, for the one information channel, each rotation signal is amplitude modulated with the information.

47. An apparatus for receiving information using an electromagnetic wave, comprising:

a transmission medium decoupler, said transmission medium decoupler receiving the electromagnetic wave having at least two multiplexed information channels to produce a plurality of received signals; and

at least a first receiving system and a second receiving system coupled to said transmission medium decoupler, the at least two receiving systems each being associated with an information channel from the at least two multiplexed information channels, each receiving system from the at least two receiving systems being associated with a combination of a carrier frequency and a rotation frequency, the first receiving system combination being different from the second receiving system combination the first receiving system including;

a first information demodulator, said information modulator demodulating a first component signal having a first carrier frequency with the information, the first component signal being from the plurality of received signals; and

a second information demodulator, said information modulator demodulating a second component signal having a second carrier frequency with the information, the second component signal being from the plurality of received signals;

the associated carrier frequency being an average of the first carrier frequency and the second carrier frequency,

the associated rotation frequency being one half of the difference of the first carrier frequency and the second carrier frequency.

48. The apparatus of claim 47, wherein, for the one information channel, the first component signal and the second component signal are modulated with the information.

49. The apparatus of claim 47, wherein, for the one information channel, the first component signal and the second component signal are amplitude modulated with the information.

50. The apparatus of claim 47, wherein, for the one information channel, the first component signal and the second component signal are phase modulated with the information.

51. The apparatus of claim 47, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are modulated with the information.

52. The apparatus of claim 47, wherein, for the one information channel, one half of the difference of the first carrier frequency and the second carrier frequency are amplitude modulated with the information.

53. A method for transmitting an electromagnetic wave, comprising:

modulating each component signal from a plurality of component signals with one rotation signal from a plurality of rotation signals, each component signal from the plurality of component signals having a carrier frequency, each rotation signal from the plurality of rotation signals having a rotation frequency; and

transmitting the electromagnetic wave on at least three antenna dipoles arranged angularly around a propagation axis and substantially within a plane perpendicular to the propagation axis, each rotation signal from the plurality of rotation signals being phase shifted an amount corresponding to the angular arrangement of an associated antenna dipole from the at least three antenna dipoles.

54. The method of claim 53, wherein:

the at least three antenna dipoles are substantially equally arranged angularly around the propagation axis,

each rotation signal from the plurality of rotation signals being phase shifted an amount substantially equal to an amount that the remaining rotation signals from the plurality of rotation signals are phase shifted.

55. A method for receiving an electromagnetic wave, comprising:

receiving the electromagnetic wave on at least three antenna dipoles arranged angularly around a propagation axis and substantially within a plane perpendicular to the propagation axis;

generating a plurality of component signals, each component signal from the plurality of component signals having a carrier frequency; and

modulating each component signal with one rotation signal from a plurality of rotation signals, each rotation signal from the plurality of rotation signals having a rotation frequency, each rotation signal from the plurality of rotation signals being phase shifted an amount corresponding to the angular arrangement of an associated antenna dipole from the at least three antenna dipoles.

56. The method of claim 55, wherein:

the at least three antenna dipoles are substantially equally arranged angularly around the propagation axis,

each rotation signal from the plurality of rotation signals being phase shifted an amount substantially equal to an amount that the remaining rotation signals from the plurality of rotation signals are phase shifted.

57. An apparatus for transmitting an electromagnetic wave, comprising:

a rotation modulator receiving a carrier signal and a rotation signal, the carrier signal having a carrier frequency, the rotation signal having a rotation frequency less than the carrier frequency, said rotation modulator splitting the rotation signal into a plurality of component rotation signals, said rotation modulator phase shifting each component rotation signal, said rotation modulator modulating the carrier signal with the component rotation signals; and

at least three antenna dipoles coupled to said rotation modulator, the at least three antenna dipoles being arranged angularly around a propagation axis and substantially within a plane perpendicular to the propagation axis, each component rotation signal being phase shifted an amount corresponding to the angular arrangement of an associated antenna dipole from the at least three antenna dipoles.

58. The apparatus of claim 57, wherein:

the at least three antenna dipoles are substantially equally arranged angularly around the propagation axis,

each component rotation signal from the plurality of component rotation signals being phase shifted an amount substantially equal to an amount that the remaining component rotation signals from the plurality of component rotation signals are phase shifted.

59. An apparatus for receiving an electromagnetic wave, comprising:

at least three antenna dipoles being arranged angularly around a propagation axis and substantially within a plane perpendicular to the propagation axis,

a rotation demodulator receiving a carrier signal and a rotation signal, the carrier signal having a carrier frequency, the rotation signal having a rotation frequency less than the carrier frequency, said rotation modulator splitting the rotation signal into component rotation signals, said rotation modulator phase shifting each component rotation signal an amount corresponding to the angular arrangement of an associated antenna dipole from the at least three antenna dipoles, said rotation modulator modulating the carrier signal with the component rotation signals.

60. The method of claim 59, wherein:

the at least three antenna dipoles are substantially equally arranged angularly around the propagation axis,

each component rotation signal from the plurality of component rotation signals being phase shifted an amount substantially equal to an amount that the remaining component rotation signals from the plurality of component rotation signals are phase shifted.

61. A method for transmitting information, comprising:

generating a plurality of component signals having a carrier frequency;

modulating each component signal with one rotation signal from a plurality of rotation signals to produce a plurality of modulated component signals, each rotation signal from the plurality of rotation signals having a rotation frequency being between the carrier frequency and zero, each rotation signal being phase shifted from the remaining rotation signals;

modulating each modulated component signal with information to produce a plurality of information modulated signals; and

transmitting an electromagnetic wave based on the information modulated signals, the electromagnetic wave having an electric field rotating about a propagation axis at the rotation frequency less than the carrier frequency and greater than zero.

62. A method for transmitting information, comprising:

generating a component signal having a carrier frequency;

modulating the component signal with information to produce a plurality of modulated component signals;

modulating each modulated component signal with one rotation signal from a plurality of rotation signals to produce a plurality of modulated rotation signals, each rotation signal from the plurality of rotation signals having a rotation frequency being between the carrier frequency and zero, each rotation signal being phase shifted from the remaining rotation signals; and

transmitting an electromagnetic wave based on the modulated rotation signals, the electromagnetic wave having an electric field rotating about a propagation axis at the rotation frequency less than the carrier frequency and greater than zero.

63. A method for receiving information, comprising:

receiving the electromagnetic wave having a plurality of wave components each being associated with an information channel, the electromagnetic wave having an electric field rotating about a propagation axis at a rotation frequency less than a carrier frequency and greater than zero, the carrier frequency and the rotation frequency being associated with the information channel;

generating a plurality of received signals based on the plurality of wave component;

generating a plurality of rotation signals each having the rotation frequency, each rotation signal being phase shifted from the remaining rotation signals;

demodulating each received signal with one rotation signal from the plurality of rotation signals to produce a plurality of demodulated received signals;

summing the plurality of demodulated received signals to produce a sum signal; and

demodulating the sum signal with the carrier signal to recover the information.

64. A method for transmitting information using an electromagnetic wave, comprising:

simultaneously transmitting a plurality of information channels, each information channel having an identical carrier frequency;

imposing on each information channel a rotating polarization which differs in rotation frequency from that of any other information channel.

65. A method for transmitting information using an electromagnetic wave, comprising:

multiplexing at least a first information channel and a second information channel, each information channel being associated with a combination of a carrier frequency and a rotation frequency, the first information channel combination being different from the second information channel combination; and

transmitting an electromagnetic wave having the multiplexed at least two information channels, the electromagnetic wave having a plurality of wave components, each wave component being associated with one information channel and each wave component having a rotating polarization about a propagation axis which differs from that of any other wave component.

67. A method for transmitting information using an electromagnetic wave, comprising:

simultaneously transmitting at least a first information channel and a second information channel, each information channel having an identical carrier frequency;

imposing on each information channel a rotating polarization, the rotating polarization of the first information channel differing in rotation frequency from that of the second information channel.

68. A method for transmitting information using an electromagnetic wave, comprising:

modulating at least a first and a second information signal with a rotation frequency to obtain a first and a second modulated rotation signal;

modulating a carrier frequency with the first and the second modulated rotation signals to obtain a first and a second modulated carrier signal;

simultaneously transmitting the first and the second modulated carrier signals in such a manner that the resulting electromagnetic wave has components containing the first and the second information signals, each component having a rotating polarization; and

the first modulating step causing the component containing the first information signal to have a rotating polarization which differs in rotation frequency from that of the component containing the second information signal.