Systems and methods for converting a stream of complex numbers into an amplitude and phase-modulated radio power signal

• US 6,411,655 B1
• Filed: 12/18/1998
• Issued: 06/25/2002
• Est. Priority Date: 12/18/1998
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Camp, William O. Jr., Dent, Paul W., Holden, Alan R.
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Nguyen, Dung X.
• Application Number:
  US09/216,466
• Time in Patent Office: 1,285 Days
• Field of Search: 375/261, 375/262, 375/263, 375/269, 375/257, 375/258, 375/279, 375/297, 375/298, 330/10, 332/145, 332/112, 332/103
• US Class Current: 375/269
• CPC Class Codes: H04L 27/361 Modulation using a single or unspecified number of carriers, e.g. with separate stages of phase and amplitude modulation

Abstract

A stream of complex numbers is converted into polar form, including an amplitude-representative part and a phase-representative part. The amplitude-representative part of each of the converted complex numbers is represented as a plurality of digits of decreasing numerical significance. The phase-representative part of each of the converted complex numbers is phase-modulated at the radio carrier frequency to produce a phase-modulated drive signal. The phase-modulated drive signal is amplified in a plurality of power amplifiers. A respective one of the power amplifiers provides a maximum output power level at a respective amplifier output that is related to a respective one of the decreasing numerical significance. The output amplitude of a respective one of the plurality of power amplifiers is controlled by applying a respective one of the plurality of digits of decreasing numerical significance to a respective one of the plurality of power amplifiers. The amplifier outputs of the plurality of power amplifiers are combined to form the modulated radio power signal.

Claims

1. A method of converting a stream of complex numbers representing a desired modulation of a radio signal into a modulated radio power signal at a radio carrier frequency, the method comprising the steps of:

converting the complex numbers into polar form, including an amplitude-representative part and a phase-representative part;

representing the amplitude-representative part of each of the converted complex numbers as a plurality of digits of decreasing numerical significance;

phase modulating the phase-representative part of each of the converted complex numbers at the radio carrier frequency, to produce a phase-modulated drive signal;

amplifying the phase-modulated drive signal in a plurality of power amplifiers, a respective one of the power amplifiers providing a contribution to the modulated radio power signal at a respective amplifier output that is related to a respective one of the digits of decreasing numerical significance;

controlling the output amplitude of a respective one of the plurality of power amplifiers by applying a respective one of the plurality of digits of decreasing numerical significance to a respective one of the plurality of power amplifiers; and

combining the amplifier outputs of the plurality of power amplifiers to form the modulated radio power signal.

2. A method according to claim 1 wherein the combining step comprises the step of applying a respective one of the amplifier outputs to a primary winding of a respective one of a plurality of transformers, the secondary windings of which are series coupled to produce the modulated radio power signal.

3. A method according to claim 1 wherein the combining step comprises the steps of:

applying a respective amplifier output to a respective quarter wave transmission line; and

coupling the quarter wave transmission lines to one another to produce the modulated radio power signal.

4. A method according to claim 1 wherein the digits are binary digits such that the step of controlling the output amplitude of a respective one of the plurality of power amplifiers comprises the step of turning a respective one of the plurality of power amplifiers on or off by applying a respective one of the plurality of digits of decreasing numerical significance to a respective one of the plurality of power amplifiers.

5. A method according to claim 1 wherein the step of converting the complex numbers into polar form comprises the step of converting the complex numbers into polar form including an amplitude-representative part having both positive and negative values, and a phase-representative part.

6. A method according to claim 5 wherein the controlling step comprises the step of controlling the output amplitude of a respective one of the plurality of power amplifiers to be either a maximum positive amplitude or a maximum negative amplitude by applying a respective one of the plurality of digits of decreasing numerical significance to a respective one of the plurality of power amplifiers.

7. A method according to claim 1 wherein the digits are ternary digits.

8. A method according to claim 7 wherein the controlling step comprises the step of controlling the output amplitude of a respective one of the plurality of power amplifiers to be either a maximum positive amplitude, a maximum negative amplitude or zero by applying a respective one of the plurality of ternary digits of decreasing numerical significance to a respective one of the plurality of power amplifiers.

9. A method according to claim 1 wherein the phase modulating step comprises the steps of phase modulating a transmit intermediate frequency and using a phase lock loop to transfer the phase modulation to the radio carrier frequency, to produce a phase-modulated drive signal.

10. A method according to claim 1 wherein the relation between the contribution and the numerical significance is provided by using different supply voltages for a respective one of the amplifiers.

11. A method according to claim 2 wherein the relation between the contribution and the numerical significance is provided by using different transformer turns ratios for a respective one of the amplifiers.

12. A method according to claim 3 wherein the relation between the contribution and the numerical significance is provided by using different line characteristic impedances for a respective one of the amplifiers.

13. A method according to claim 1 wherein the relation between the contribution and the numerical significance is provided by using at least one of different supply voltages for respective amplifiers and different transformer turns ratios and different transmission line impedances for combining a respective one of the amplifier outputs.

14. A system for converting a stream of complex numbers representing a desired modulation of a radio signal into a modulated radio power signal at a radio carrier frequency, the system comprising:

a processor that converts the complex numbers into polar form, including an amplitude-representative part and a phase-representative part, and that represents the amplitude-representative part of each of the converted complex numbers as a plurality of digits of decreasing numerical significance;

a phase modulator that modulates the phase-representative part of each of the converted complex numbers at the radio carrier frequency, to produce a phase-modulated drive signal;

a plurality of power amplifiers, a respective one which provides a contribution to the modulated radio power signal at a respective amplifier output that is related to a respective one of the digits of decreasing numerical significance, a respective one of the plurality of digits of decreasing numerical significance being applied to a respective one of the plurality of power amplifiers to thereby control the output amplitude of a respective one of the plurality of power amplifiers; and

a combining circuit that combines the amplifier outputs of the plurality of power amplifiers to form the modulated radio power signal.

15. A system according to claim 14 wherein the combining circuit comprises a plurality of transformers each having a primary winding and a secondary winding, a respective primary winding being coupled to a respective power amplifier, the plurality of secondary windings being series coupled to produce the modulated radio power signal.

16. A system according to claim 14 wherein the combining circuit comprises a plurality of quarter wavelength transmission lines, a respective one of which is coupled between a respective power amplifier and an output node to produce the modulated radio power signal at the output node.

17. A system according to claim 14 wherein the digits are binary digits such that a respective one of the plurality of power amplifiers is turned on or off by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

18. A system according to claim 14 wherein the processor converts the complex numbers into polar form, including an amplitude-representative part having both positive and negative values, and a phase-representative part.

19. A system according to claim 18 wherein the output amplitude of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive amplitude or a maximum negative amplitude by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

20. A system according to claim 14 wherein the digits are ternary digits and wherein the output amplitude of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive amplitude, a maximum negative amplitude or zero by the respective one of the plurality of ternary digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

21. A system according to claim 14 wherein the phase modulator comprises:

an intermediate frequency phase modulator that phase modulates a transmit intermediate frequency; and

a phase lock loop that is responsive to the intermediate frequency phase modulator to transfer the phase modulation to the radio carrier frequency, to produce a phase-modulated drive signal.

22. A system according to claim 14 wherein the relation between the contribution and the numerical significance is provided by using different supply voltages for a respective one of the amplifiers.

23. A system according to claim 15 wherein the relation between the contribution and the numerical significance is provided by using different transformer turns ratios for a respective one of the amplifiers.

24. A system according to claim 16 wherein the relation between the contribution and the numerical significance is provided by using different line characteristic impedances for a respective one of the amplifiers.

25. A system according to claim 14 where the relation between the contribution and the numerical significance is provided by using at least one of different supply voltages for respective amplifiers and different transformer turns ratios and different transmission line impedances for combining a respective one of the amplifier outputs.

26. A system for converting a stream of complex numbers representing a desired modulation of a radio signal into a modulated radio power signal at a radio carrier frequency, the system comprising:

means for converting the complex numbers into polar form, including an amplitude-representative part and a phase-representative part, and for representing the amplitude-representative part of each of the converted complex numbers as a plurality of digits of decreasing numerical significance;

means for phase modulating the phase-representative part of each of the converted complex numbers at the radio carrier frequency, to produce a phase-modulated drive signal;

means for power amplifying the phase-modulated drive signal in a plurality of power amplifiers, a respective one which provides a contribution to the modulated radio power signal at a respective amplifier output that is related to a respective one of the digits of decreasing numerical significance, a respective one of the plurality of digits of decreasing numerical significance being applied to a respective one of the plurality of power amplifiers to thereby control the output amplitude of a respective one of the plurality of power amplifiers; and

means for combining the amplifier outputs of the plurality of power amplifiers to form the modulated radio power signal.

27. A system according to claim 26 wherein the combining means comprises:

means for series combining the plurality of power levels to produce the modulated radio power signal.

28. A system according to claim 26 wherein the combining means comprises:

means for converting the plurality of power levels to a plurality of output currents; and

means for combining the plurality of output currents to produce the modulated radio power signal.

29. A system according to claim 26 wherein the digits are binary digits such that a respective one of the plurality of power amplifiers is turned on or off by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

30. A system according to claim 26 wherein the means for converting comprises means for converting the complex numbers into polar form, including an amplitude-representative part having both positive and negative values, and a phase-representative part.

31. A system according to claim 30 wherein the output amplitude of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive amplitude or a maximum negative amplitude by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

32. A system according to claim 26 wherein the digits are ternary digits and wherein the output amplitude of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive amplitude, a maximum negative amplitude or zero by the respective one of the plurality of ternary digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

33. A system according to claim 26 wherein the relation between the contribution and the numerical significance is provided by using different supply voltages for a respective one of the amplifiers.

34. A system according to claim 27 wherein the relation between the contribution and the numerical significance is provided by using different transformer turns ratios for a respective one of the amplifiers.

35. A system according to claim 28 wherein the relation between the contribution and the numerical significance is provided by using different line characteristic impedances for a respective one of the amplifiers.

36. A system according to claim 26 wherein the relation between the contribution and the numerical significance is provided by using at least one of different supply voltages for respective amplifiers and different transformer turns ratios and different transmission line impedances for combining a respective one of the amplifier outputs.

37. A system for converting a stream of complex numbers representing a desired modulation of a radio signal into a modulated radio power signal at a radio carrier frequency, the system comprising:

a processor that converts the complex numbers into polar form, including an amplitude-representative part and a phase-representative part, and that represents the amplitude-representative part of each of the converted complex numbers as a plurality of digits of decreasing numerical significance;

a phase modulator that phase modulates the phase-representative part of each of the converted complex numbers at the radio carrier frequency, to produce a phase-modulated drive signal;

a plurality of power amplifiers, a respective one which provides an output voltage level at a respective amplifier output thereof, a respective one of the plurality of digits of decreasing numerical significance being applied to a respective one of the plurality of power amplifiers; and

a combining circuit that combines the amplifier outputs of the plurality of power amplifiers according to a combining ratio to produce the modulated radio power signal, at least one of the output voltage level and the combining ratio being selected such that the modulated radio power signal is related to the numerical significance of the plurality of digits.

38. A system according to claim 37 wherein each of the power amplifiers produces same output voltage level and wherein the combining ratio is selected such that the outputs of the power amplifiers are combined according to a ratio that is related to the numerical significance of the digit that is applied to the respective power amplifier.

39. A system according to claim 37 wherein the combining ratio is unity and wherein the output voltage level of a respective power amplifier is related to the numerical significance of the digit that is applied thereto.

40. A system according to claim 37 wherein both the output voltage level and the combining ratio are selected such that the modulated radio power signal is related to the numerical significance of the plurality of digits.

41. A system according to claim 37 wherein the combining circuit comprises a plurality of transformers each having a primary winding and a secondary winding, a respective primary winding being coupled to a respective power amplifier, the plurality of secondary windings being series coupled to produce the modulated radio power signal.

42. A system according to claim 37 wherein the combining circuit comprises a plurality of quarter wavelength transmission lines, a respective one of which is coupled between a respective power amplifier and an output node to produce the modulated radio power signal at the output node.

43. A system according to claim 37 wherein the digits are binary digits such that a respective one of the plurality of power amplifiers is turned on or off by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

44. A system according to claim 37 wherein the processor converts the complex numbers into polar form, including an amplitude-representative part having both positive and negative values, and a phase-representative part.

45. A system according to claim 44 wherein the output voltage level of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive voltage level or a maximum negative voltage level by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

46. A system according to claim 37 wherein the digits are ternary digits and wherein the output voltage level of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive voltage level, a maximum negative voltage level or zero by the respective one of the plurality of ternary digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

47. A system for converting a stream of complex numbers representing a desired modulation of a radio signal into a modulated radio power signal at a radio carrier frequency, the system comprising:

means for converting the complex numbers into polar form, including an amplitude-representative part and a phase-representative part, and for representing the amplitude-representative part of each of the converted complex numbers as a plurality of digits of decreasing numerical significance;

means for phase modulating the phase-representative part of each of the converted complex numbers at the radio carrier frequency, to produce a phase-modulated drive signal;

means for power amplifying the phase-modulated drive signal in a plurality of power amplifiers, a respective one which provides an output voltage level at a respective amplifier output, a respective one of the plurality of digits of decreasing numerical significance being applied to a respective one of the plurality of power amplifiers; and

means for combining the amplifier outputs of the plurality of power amplifiers according to a combining ratio to produce the modulated radio power signal, at least one of the output voltage level and the combining ratio being selected such that the modulated radio power signal is related to the numerical significance of the plurality of digits.

48. A system according to claim 47 wherein the means for power amplifying comprises means for power amplifying the phase-modulated drive signal to same output voltage level in the plurality of power amplifiers, and wherein the combining ratio is selected such that the amplifier outputs are combined according to a ratio that is related to the numerical significance of the digits that are associated with the respective phase modulated output.

49. A system according to claim 47 wherein the combining ratio is unity and wherein the respective output voltage levels are related to the numerical significance of the digits that are associated therewith.

50. A system according to claim 47 wherein both the respective output voltage level and the combining ratio are selected such that the modulated radio power signal is related to the numerical significance of the plurality of digits.

51. A system according to claim 47 wherein the combining means comprises:

means for series combining the plurality of power levels to produce the modulated radio power signal.

52. A system according to claim 47 wherein the combining means comprises:

means for converting the plurality of amplifier output voltage levels to a plurality of amplifier output currents; and

means for combining the plurality of amplifier output currents to produce the modulated radio power signal.

53. A system according to claim 47 wherein the digits are binary digits such that a respective one of the plurality of power amplifiers is turned on or off by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

54. A system according to claim 47 wherein the means for converting comprises means for converting the complex numbers into polar form, including an amplitude-representative part having both positive and negative values, and a phase-representative part.

55. A system according to claim 54 wherein the output voltage level of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive voltage level or a maximum negative voltage level by the respective one of the plurality of digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

56. A system according to claim 47 wherein the digits are ternary digits and wherein the output voltage level of a respective one of the plurality of power amplifiers is controlled to be either a maximum positive voltage level, a maximum negative voltage level or zero by the respective one of the plurality of ternary digits of decreasing numerical significance that is applied to a respective one of the plurality of power amplifiers.

57. A method for converting a stream of complex numbers representing a desired modulation of a radio signal into a modulated radio power signal at a radio carrier frequency, the method comprising the steps of:

converting the complex numbers into polar form, including an amplitude-representative part and a phase-representative part;

representing the amplitude-representative part of each of the converted complex numbers as a plurality of digits of decreasing numerical significance;

phase modulating the phase-representative part of each of the converted complex numbers at the radio carrier frequency, to produce a phase-modulated drive signal;

power amplifying the phase-modulated drive signal in a plurality of power amplifiers, a respective one which provides an output voltage level at a respective amplifier output;

applying a respective one of the plurality of digits of decreasing numerical significance to a respective one of the plurality of power amplifiers; and

combining the amplifier outputs of the plurality of power amplifiers according to a combining ratio to produce the modulated radio power signal, at least one of the output voltage level and the combining ratio being selected such that the modulated radio power signal is related to the numerical significance of the plurality of digits.

58. A method according to claim 57 wherein the power amplifying step comprises the step of power amplifying the phase-modulated drive signal to same output voltage level in the plurality of power amplifiers, and wherein the combining ratio is selected such that the amplifier outputs are combined according to a ratio that is related to the numerical significance of the digits that are associated with the respective phase modulated output.

59. A method according to claim 57 wherein the combining ratio is unity and wherein the respective output voltage levels are related to the numerical significance of the digits that are associated therewith.

60. A method according to claim 57 wherein both the respective output voltage levels and the combining ratio are selected such that the modulated radio power signal is related to the numerical significance of the plurality of digits.