Harmonic cancellation mixer

• US 6,766,158 B1
• Filed: 03/30/2001
• Issued: 07/20/2004
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Rampmeier, Keith J., Molnar, Alyosha C., Magoon, Rahul
• Primary Examiner(s): NGUYEN, THUAN T
• Application Number:
  US09/823,314
• Time in Patent Office: 1,208 Days
• Field of Search: 455/323, 455/76, 455/78, 455/88, 455/208, 455/552.1, 455/553.1, 455/131, 455/136, 455/322, 455/324, 455/266, 455/234.1, 455/73, 455/326, 455/112, 455/130, 455/147, 331/2, 331/46, 331/48, 342/368
• US Class Current: 455/323
• CPC Class Codes: H03D 2200/0086 Reduction or prevention of harmonic frequencies
• CPC Class Codes: H03D 7/163 the local oscillations of at least two of the frequency changers being derived from a single oscillator
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

A mixing system divides a local oscillator (“LO”) signal into two signals having a predetermined phase difference, mixes each of the two signal with an input signal to produce a mixed signal, and then combines the mixed signals to produce an output signal having substantially no third-order mixing products.

Claims

1. A signal processing system comprising:

a plurality of mixers, each configured to receive a local oscillator signal and an input signal, and configured to provide a mixer output;

where a phase of a first local oscillator signal provided to a first mixer is different from a phase of a second local oscillator signal provided to a second mixer;

where the plurality of mixer outputs are combined; and

where a phase difference between the first local oscillator signal and the second local oscillator signal is predetermined to cause the first mixer to produce a third-order mixing product that substantially cancels out a third-order mixing product that is produced by the second mixer.

2. The signal processing system of claim 1, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 55°

and 65°

.

3. The signal processing system of claim 1, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 45°

and 75°

.

4. The signal processing system of claim 1, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 35°

and 85°

.

5. The signal processing system of claim 1, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 26°

and 46°

.

6. The signal processing system of claim 1, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 16°

and 56°

.

7. The signal processing system of claim 1, where the phase difference between the first local oscillator signal and the second local oscillator signal is substantially 60°

.

8. The signal processing system of claim 1, further comprising a phase shifting circuit for shifting a phase of a local oscillator signal.

9. The signal processing system of claim 8, where the signal processing system is a downconverter.

10. The signal processing system of claim 8, where the signal processing system is an upconverter.

11. The signal processing system of claim 8, where the signal processing system is a modulator.

12. The signal processing system of claim 8, where the signal processing system is a demodulator.

13. The signal processing system of claim 8, where the signal processing system is a mobile telephone.

14. The signal processing system of claim 1, where the phase difference is substantially 36°

.

15. The signal processing system of claim 14, where the first mixer produces a fifth-order mixing product that substantially cancels out a fifth-order mixing product that is produced by the second mixer.

16. The signal processing system of claim 14, further comprising a phase shifting circuit for shifting a phase of a local oscillator signal.

17. A method for processing signals comprising:

receiving a plurality of local oscillator signals and a plurality of input signals at a plurality of mixers, where each of the plurality of mixers receives at least one local oscillator signal and at least one input signal;

generating a plurality of mixer outputs, where each of the plurality of mixers generates at least one mixer output;

combining the plurality of mixer outputs;

where a phase of a first local oscillator signal provided to a first mixer is different from a phase of a second local oscillator signal provided to a second mixer; and

where a phase difference between the first local oscillator signal and the second local oscillator signal is predetermined to cause the first mixer to produce a third-order mixing product that substantially cancels out a third-order mixing product that is produced by the second mixer.

18. The method of claim 17, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 55°

and 65°

.

19. The method, of claim 17, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 45°

and 75°

.

20. The method of claim 17, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 35°

and 85°

.

21. The method of claim 17, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 26°

and 46°

.

22. The method of claim 17, where the phase difference between the first local oscillator signal and the second local oscillator signal is between 16°

and 56°

.

23. The method of claim 17, where the phase difference between the first local oscillator signal and the second local oscillator signal is substantially 60°

.

24. The method of claim 23, where the method is implemented in an upconverter.

25. The method of claim 23, where the method is implemented in a downconverter.

26. The method of claim 23, where the method is implemented in a demodulator.

27. The method of claim 23, where the method is implemented in a modulator.

28. The method of claim 23, where the method is implemented in a mobile telephone.

29. The method of claim 17, where the phase difference between the first local oscillator signal and the second local oscillator signal is substantially 36°

.

30. The method of claim 29, where the first mixer produces a fifth-order mixing product that substantially cancels out a fifth-order mixing product that is produced by the second mixer.

31. A signal processing system comprising:

a first mixer for receiving a first local oscillator signal and a first input signal, and for generating a first mixer output;

a second mixer for receiving a second local oscillator signal and a second input signal and for generating a second mixer output;

where a phase of the first local oscillator signal and a phase of the second local oscillator signal differ by substantially 60°

; and

where the first mixer output and the second mixer output are combined.

32. The signal processing system of claim 31, where a first signal component contained in the first mixer output and a second signal component contained in the second mixer output have substantially equal magnitudes and a phase difference substantially equal to 180°

.

33. The signal processing system of claim 32, where the first signal component and the second signal component are third-order mixing products that substantially cancel each other after the first mixer output is combined with the second mixer output.

34. The signal processing system of claim 33, where the first input signal and the second input signal are substantially identical and are derived from a common source.

35. The signal processing system of claim 34, where the first local oscillator signal and the second local oscillator signal are derived from a common source.

36. The signal processing system of claim 31, where the signal processing system is an upconverter.

37. The signal processing system of claim 31, where the signal processing system is a downconverter.

38. The signal processing system of claim 31, where the signal processing system is a modulator.

39. The signal processing system of claim 31, where the signal processing system is a demodulator.

40. The signal processing system of claim 31, where the signal processing system is a mobile telephone.

41. A signal processing system comprising:

a first mixer for receiving a first local oscillator signal and a first input signal, and for generating a first mixer output;

a second mixer for receiving a second local oscillator signal and a second input signal and for generating a second mixer output;

where a phase of the first local oscillator signal and a phase of the second local oscillator signal differ by substantially 36°

; and

where the first mixer output and the second mixer output are combined.

42. The signal processing system of claim 41, where an output from a third mixer and an output from a fourth mixer are combined with the first mixer output and the second mixer output.

43. The signal processing system of claim 42, where a third-order mixing product contained in the first mixer output substantially cancels out a third-order mixing product contained in the output from the third mixer.

44. The signal processing system of claim 43, where a third-order mixing product contained in the second mixer output substantially cancels out a third-order mixing product contained in the output from the fourth mixer.

45. The signal processing system of claim 41, further comprising a phase offsetting divider for providing a phase altered local oscillator signal.

46. The signal processing system of claim 41, where the signal processing system is an upconverter.

47. The signal processing system of claim 41, where the signal processing system is a downconverter.

48. The signal processing system of claim 41, where the signal processing system is a modulator.

49. The signal processing system of claim 41, where the signal processing system is a demodulator.

50. The signal processing system of claim 41, where the signal processing system is a mobile telephone.

51. A signal processing system comprising:

a first mixer for receiving a first local oscillator signal and a first input signal, and for generating a first mixer output;

a second mixer for receiving a second local oscillator signal and a second input signal and for generating a second mixer output;

a third mixer for receiving a third local oscillator signal and a third input signal, and for generating a third mixer output;

a fourth mixer for receiving a fourth local oscillator signal and a fourth input signal and for generating a fourth mixer output;

where a phase of the first local oscillator signal and a phase of the second local oscillator signal have a phase difference;

where a phase of the third local oscillator signal and a phase of the fourth local oscillator signal have a phase difference; and

where the first mixer output, the second mixer output, the third mixer output, and the fourth mixer output are combined.

52. The signal processing system of claim 51, where a phase of the first local oscillator signal and a phase of the second local oscillator signal differ by substantially 36°

.

53. The signal processing system of claim 52, where a phase of the third local oscillator signal and a phase of the fourth local oscillator signal differ by substantially 36°

.

54. The signal processing system of claim 53, where a signal that is used to derive the first local oscillator signal and the second local oscillator signal has a phase that differs by substantially 60°

from the a signal that is used to derive the third local oscillator signal and the fourth local oscillator signal.

55. The signal processing system of claim 54, where the average phase for the first and second local oscillator signals differs by substantially 60°

from the average phase for the third and fourth local oscillator signals.

56. The signal processing system of claim 55, where the first mixer output, the second mixer output, the third mixer output, and the fourth mixer output, each have a third-order mixing product.

57. The signal processing system of claim 56, where the third harmonic components of the first mixer, the second mixer, the third mixer, and the fourth mixer have a sum that is substantially equal to zero.

58. The signal processing system of claim 57, where the first mixer output, the second mixer output, the third mixer output, and the fourth mixer output, each have a fifth harmonic component.

59. The signal processing system of claim 51, where the fifth harmonic components of the first mixer, the second mixer, the third mixer, and the fourth mixer have a sum that is substantially equal to zero.

60. The signal processing system of claim 51, further comprising a phase offsetting divider for providing a phase altered local oscillator signal.

61. The signal processing system of claim 51, where the signal processing system is an upconverter.

62. The signal processing system of claim 51, where the signal processing system is a downconverter.

63. The signal processing system of claim 51, where the signal processing system is a modulator.

64. The signal processing system of claim 51, where the signal processing system is a demodulator.

65. The signal processing system of claim 51, where the signal processing system is a mobile telephone.

66. A method for mixing signals comprising:

receiving a first local oscillator signal and a first input signal at a first mixer;

generating a first mixer output at the first mixer;

receiving a second local oscillator signal and a second input signal at a second mixer;

generating a second mixer output at the second mixer;

combining the first mixer output and the second mixer output; and

where a phase of the first local oscillator signal and a phase of the second local oscillator signal have a 60°

phase difference.

67. The method of claim 66, where a first signal component contained in the first mixer output and a second signal component contained in the second mixer output have substantially equal magnitudes and a phase difference substantially equal to 180°

.

68. The method of claim 67, where the first signal component and the second signal component are third-order mixing terms that substantially cancel each other after the first mixer output is combined with the second mixer output.

69. The method of claim 68, where the first input signal and the second input signal are substantially identical and are derived from a common source.

70. The method of claim 69, where the first local oscillator signal and the second local oscillator signal are derived from a common source.

71. A method for mixing signals comprising:

receiving a first local oscillator signal and a first input signal at a first mixer;

generating a first mixer output at the first mixer;

receiving a second local oscillator signal and a second input signal at a second mixer;

generating a second mixer output at the second mixer;

combining the first mixer output and the second mixer output; and

where a phase of the first local oscillator signal and a phase of the second local oscillator signal have a 36°

phase difference.

72. The method of claim 71, further comprising:

combining an output from a third mixer and an output from a fourth mixer with the first mixer output and the second mixer output.

73. The method of claim 72, where a third-order mixing product contained in the first mixer output substantially cancels out a third-order mixing product contained in the third mixer output after the first mixer output and the third mixer output are combined.

74. The method of claim 73, where a third-order mixing product contained in the second mixer output substantially cancels out a third-order mixing product contained in the fourth mixer output after the second mixer output and the fourth mixer output are combined.