Systems and methods for converting a stream of complex numbers into a modulated radio power signal

• US 6,201,452 B1
• Filed: 12/10/1998
• Issued: 03/13/2001
• Est. Priority Date: 12/10/1998
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Camp, William O. Jr., Dent, Paul W., Holden, Alan R.
• Primary Examiner(s): KINKEAD, ARNOLD M
• Application Number:
  US09/208,912
• Time in Patent Office: 824 Days
• Field of Search: 332/103, 332/145, 330/252, 330/124.R, 330/10, 363/43, 307/82, 375/298, 375/300
• US Class Current: 332/103
• CPC Class Codes: H03F 1/0294 using vector summing of two or more constant amplitude phase-modulated signals
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04L 27/2071 in which the data are represented by the carrier phase, e.g. systems with differential coding

Abstract

Modulation systems and methods can modulate a stream of complex numbers representing a desired modulation of a radio signal by representing a real part of each of the complex numbers in a stream of complex numbers representing a desired modulation of a radio signal, as a plurality of first digits of decreasing numerical significance and representing an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance. A respective one of the first digits and a respective one of the second digits of like numerical significance are grouped to form a plurality of phase control symbols. A respective phase control symbol is then used to control the phase of an output signal at the radio carrier frequency from a respective one of the plurality of power amplifiers. Each of the power amplifiers provides an output power level that is related to the numerical significance of the first and second digits that form the associated phase control symbol. The output power levels of the plurality of power amplifiers are combined to thereby form the modulated radio power signal.

Claims

1. A method of generating a modulated radio power signal at a radio carrier frequency, the method comprising the steps of:

sampling an information signal at a predetermined sampling rate to produce a series of samples of the information signal;

generating a stream of complex numbers representing the series of samples of the information signal;

representing a real part of each of the complex numbers as a plurality of first digits of decreasing numerical significance;

representing an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance;

grouping a respective one of the first digits and a respective one of the second digits of like numerical significance to form a plurality of phase control symbols;

using a respective phase control symbol to control the phase of an output signal at the radio carrier frequency from a respective one of a plurality of power amplifiers, each of the power amplifiers providing an output power level at an amplifier output that is related to the numerical significance of the first and second digits that form the associated phase control symbol; 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 serially 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 further comprising the steps of:

coupling at least two of the phase control symbols of the least numerical significance to at least one linear amplifier to produce a linear output; and

wherein the combining step comprises the step of combining the linear output and the amplifier outputs of the plurality of power amplifiers to form the modulated radio power signal.

5. A method according to claim 1 wherein the digits are binary digits such that each of the phase control symbols is one of four values.

6. A method according to claim 1 wherein the plurality of power amplifiers are a plurality of saturated power amplifiers that produce a constant radio frequency voltage output.

7. A method according to claim 1 wherein the plurality of power amplifiers are a plurality of bilateral power amplifiers that allow current to flow from and to an amplifier power supply.

8. A system for generating a modulated radio power signal at a radio carrier frequency, the system comprising:

a sampler that samples an information signal at a predetermined sampling rate to produce a series of samples of the information signal;

a device that generates a stream of complex numbers representing the series of samples of the information signal;

a processor that represents a real part of each of the complex numbers as a plurality of first digits of decreasing numerical significance, and that represents an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance to form a plurality of phase control symbols from a respective one of the first digits and a respective one of the second digits of like numerical significance;

a plurality of power amplifiers, a respective one of which amplifies a respective one of the phase control symbols modulated on the radio carrier frequency, each of the power amplifiers providing an output power level at an amplifier output that is related to the numerical significance of the first and second digits that form the associated phase control symbol; and

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

9. A system according to claim 8 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 serially coupled to produce the modulated radio power signal.

10. A system according to claim 8 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.

11. A system according to claim 8 wherein the digits are binary digits such that each of the phase control symbols has one of four values.

12. A system according to claim 8 wherein the power amplifiers are saturated power amplifiers that produce a constant radio frequency voltage output at the amplifier output.

13. A system according to claim 8 wherein the power amplifiers are bilateral power amplifiers that allow current flow from and to an amplifier power supply.

14. A system according to claim 8 further comprising at least one linear amplifier that is associated with at least two of the phase control symbols of least numerical significance, to generate a linear output voltage at an output thereof that is proportional to the combined values of the at least two of the first and second digits of least numerical significance, wherein the combining circuit combines the output of the at least one linear amplifier and the amplifier outputs of the power amplifiers.

15. A system for generating a modulated radio power signal at a radio carrier frequency, the system comprising:

means for sampling an information signal at a predetermined sampling rate to produce a series of samples of the information signal;

means for generating a stream of complex numbers representing the series of samples of the information signal;

means for representing a real part of each of the complex numbers as a plurality of first digits of decreasing numerical significance and for representing an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance to form a plurality of phase control symbols from a respective one of the first digits and a respective one of the second digits of like numerical significance;

means for power amplifying a respective one of the phase control symbols modulated on the radio carrier frequency to provide a plurality of output power levels that are related to the numerical significance of the first and second digits that form the associated phase control symbol; and

means for combining the output power levels to form the modulated radio power signal.

16. A system according to claim 15 wherein the combining means comprises:

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

17. A system according to claim 15 wherein the combining means comprises:

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

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

18. A system according to claim 15 wherein the digits are binary digits such that each of the phase control symbols has one of four values.

19. A system according to claim 15 further comprising means for generating a linear output voltage that is proportional to the combined values of at least two of the first and second digits of least numerical significance, wherein the combining means comprises means for combining the linear output voltage and the output power levels to form the modulated radio power signal.

20. A system for generating a modulated radio power signal at a radio carrier frequency, the system comprising:

a sampler that samples an information signal at a predetermined sampling rate to produce a series of samples of the information signal;

a device that generates a stream of complex numbers representing the series of samples of the information signal;

a processor that represents a real part of each of the complex numbers as a plurality of first digits of decreasing numerical significance, and that represents an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance;

a plurality of phase modulators, a respective one of which is responsive to a respective one of the plurality of first digits and a respective one of the plurality of second digits of like numerical significance, and to the radio carrier frequency, to produce a phase modulated output at the radio carrier frequency;

a plurality of power amplifiers, a respective one of which amplifies a respective one of the phase modulated outputs of the phase modulators to an amplifier power level at an amplifier output thereof; and

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

21. A system according to claim 20 wherein each of the power amplifiers produces same amplifier power level and wherein the combining ratio is selected such that the amplifier outputs of the power amplifiers are combined according to a ratio that is related to the numerical significance of the digits that are associated with the respective power amplifier.

22. A system according to claim 20 wherein the combining ratio is unity and wherein the amplifier power level of a respective power amplifier is related to the numerical significance of the digits that are associated therewith.

23. A system according to claim 20 wherein both the amplifier power level and the combining ratio are selected such that the modulated radio power signal is related to the numerical significance of the plurality of first and second digits.

24. A system according to claim 20 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 serially coupled to produce the modulated radio power signal.

25. A system according to claim 20 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.

26. A system according to claim 20 wherein the digits are binary digits such that each of the phase modulated outputs has one of four values.

27. A system according to claim 20 wherein the power amplifiers are saturated power amplifiers that produce a constant radio frequency voltage output at the amplifier power level.

28. A system according to claim 20 wherein the power amplifiers are bilateral power amplifiers that allow current flow from and to an amplifier power supply.

29. A system according to claim 20 further comprising at least one linear amplifier that is associated with at least two of the first and second digits of least numerical significance, to generate a linear output voltage at an output thereof that is proportional to the combined values of the at least two of the first and second digits of least numerical significance, wherein the combining circuit combines the output of the at least one linear amplifier and the amplifier outputs of the power amplifiers.

30. A system for generating a modulated radio power signal at a radio carrier frequency, the system comprising:

means for sampling an information signal at a predetermined sampling rate to produce a series of samples of the information signal;

means for generating a stream of complex numbers representing the series of samples of the information signal;

means for representing a real part of each of the complex numbers as a plurality of first digits of decreasing numerical significance and for representing an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance;

means for producing a plurality of phase modulated outputs at the radio carrier frequency in response to the plurality of first digits, the plurality of second digits and the radio carrier frequency;

means for amplifying a respective one of the phase modulated outputs to a respective power level; and

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

31. A system according to claim 30 wherein the means for amplifying comprises means for amplifying a respective one of the phase modulated outputs to same power level and wherein the combining ratio is selected such that the phase modulated 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.

32. A system according to claim 30 wherein the combining ratio is unity and wherein the respective power levels are related to the numerical significance of the digits that are associated therewith.

33. A system according to claim 30 wherein both the respective power level and the combining ratio are selected such that the modulated radio power signal is related to the numerical significance of the plurality of first and second digits.

34. A system according to claim 30 wherein the combining means comprises:

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

35. A system according to claim 30 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.

36. A system according to claim 30 wherein the digits are binary digits such that each of the phase modulated outputs has one of four values.

37. A system according to claim 30 further comprising means for generating a linear output voltage that is proportional to the combined values of at least two of the first and second digits of least numerical significance, wherein the combining means comprises means for combining the linear output voltage and the output power levels to form the modulated radio power signal.

38. A method for generating a modulated radio power signal at a radio carrier frequency, the method comprising the steps of:

sampling an information signal at a predetermined sampling rate to produce a series of samples of the information signal;

generating a stream of complex numbers representing the series of samples of the information signal;

representing a real part of each of the complex numbers as a plurality of first digits of decreasing numerical significance;

representing an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance;

modulating a respective one of the plurality of first digits and a respective one of the plurality of second digits of like numerical significance onto the radio carrier frequency, to produce a plurality of phase modulated outputs at the radio carrier frequency;

amplifying a respective one of the phase modulated outputs to a power level; and

combining the amplified phase modulated outputs according to a combining ratio to produce the modulated radio power signal, at least one of the power level and the combining ratio being selected such that the modulated radio power signal is related to the numerical significance of the plurality of first and second digits.

39. A method according to claim 38 wherein the amplifying step comprises the step of amplifying a respective one of the phase modulated outputs to same power level;

wherein the combining ratio is selected such that the amplified phase modulated outputs are combined according to a combining ratio that is related to the numerical significance of the digits that are associated with the respective phase modulated output.

40. A method according to claim 38 wherein the combining ratio is unity and wherein the respective power levels are related to the numerical significance of the digits that are associated therewith.

41. A method according to claim 38 wherein both the respective power level and the combining ratio are selected such that the modulated radio power signal is related to the numerical significance of the plurality of first and second digits.

42. A method according to claim 38 wherein the combining step comprises the step of:

serially combining the plurality of power levels to produce the modulated radio power signal.

43. A method according to claim 38 wherein the combining step comprises the steps of:

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

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

44. A method according to claim 38 wherein the digits are binary digits such that each of the phase modulated outputs has one of four values.

45. A method according to claim 38 further comprising the step of generating a linear output voltage that is proportional to the combined values of at least two of the first and second digits of least numerical significance, wherein the combining step comprises the step of combining the linear output voltage and the output power levels to form the modulated radio power signal.

46. A method according to claim 38 wherein the real part is represented at successive odd instants of a clock and the imaginary part is represented at successive even instants of the clock.