90° phase shifter and image rejection mixer

• US 6,321,076 B1
• Filed: 07/15/1999
• Issued: 11/20/2001
• Est. Priority Date: 07/17/1998
• Status: Expired due to Term

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Corporation
• Inventors: Jianqin, Wang
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Tran, Congvan
• Application Number:
  US09/353,357
• Time in Patent Office: 859 Days
• Field of Search: 455/323, 455/326, 455/302, 455/304, 455/305, 455/313, 455/131, 455/189.1, 455/314, 375/268, 375/272, 375/273, 375/274, 375/275, 375/279, 375/281, 375/280
• US Class Current: 455/323
• CPC Class Codes: H03H 7/19 Two-port phase shifters providing a predetermined phase shift, e.g. "all-pass" filters

Abstract

A phase shift circuit includes a first phase shifter, second phase shifter, and adder. The first phase shifter receives an input signal and obtains first and second intermediate phase shift signals having different phases. The second phase shifter obtains first and second outputs by shifting phases of the first and second intermediate phase shift signals. The adder generates a phase shift output signal by adding the first and second outputs from the second phase shifter. A phase shifting device, oscillation circuit, and image rejection mixer are also disclosed.

Claims

1. A phase shift circuit comprising:

a first phase shifter for receiving an input signal and obtaining first and second intermediate phase shift signals having different phases;

a second phase shifter for obtaining first and second outputs by shifting phases of the first and second intermediate phase shift signals; and

an adder for generating a phase shift output signal by adding the first and second outputs from said second phase shifter,

wherein each of said first and second phase shifters comprises either a first type phase shifter exhibiting a substantially constant relative phase difference between input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative gain or a second type phase shifter exhibiting a substantially constant relative gain of input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative phase difference.

2. A phase shifting device comprising:

a first phase shifter for receiving an input signal and obtaining first and second intermediate phase shift signals having different phases;

a second phase shifter for obtaining first and second outputs by shifting phases of the first and second intermediate phase shift signals;

a third phase shifter for obtaining third and fourth outputs by shifting phases of the first and second intermediate phase shift signals;

a first adder for generating a first phase shift output signal by adding the first and second outputs from said second phase shifter; and

a second adder for generating a second phase shift output signal by adding the third and fourth outputs from said third phase shifter.

3. A device according to claim 2, wherein each of said first, second, and third phase shifters comprises either a first type phase shifter exhibiting a substantially constant relative phase difference between input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative gain or a second type phase shifter exhibiting a substantially constant relative gain of input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative phase difference.

4. A phase shifting device comprising:

a first phase shifter for receiving a first input signal and obtaining first and second intermediate phase shift signals having different phases;

a second phase shifter for obtaining first and second outputs by shifting phases of the first and second intermediate phase shift signals;

a first adder for generating a first phase shift output signal by adding the first and second outputs from said second phase shifter;

a third phase shifter for receiving a second input signal out of phase with the first input signal and obtaining third and fourth intermediate phase shift signals;

a fourth phase shifter for obtaining third and fourth outputs by further shifting phases of the third and fourth intermediate phase shift signals; and

a second adder for generating a second phase shift output signal by adding the third and fourth outputs from said fourth phase shifter.

5. A device according to claim 4, wherein each of said first, second, third, and fourth phase shifters comprises either a first type phase shifter exhibiting a substantially constant relative phase difference between input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative gain or a second type phase shifter exhibiting a substantially constant relative gain of input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative phase difference.

6. An oscillation circuit comprising:

an oscillator for generating an oscillation signal having a predetermined frequency; and

an oscillation circuit for receiving the oscillation signal from said oscillator and generating first and second phase shift output signals,

said oscillation circuit including;

a first phase shifter for receiving an input signal and obtaining first and second intermediate phase shift signals having different phases;

a second phase shifter for obtaining first and second outputs by shifting phases of the first and second intermediate phase shift signals;

a third phase shifter for obtaining third and fourth outputs by shifting phases of the first and second intermediate phase shift signals;

a first adder for generating a first phase shift output signal by adding the first and second outputs from said second phase shifter; and

a second adder for generating a second phase shift output signal by adding the third and fourth outputs from said third phase shifter.

7. A device according to claim 6, wherein each of said first, second, and third phase shifters comprises either a first type phase shifter exhibiting a substantially constant relative phase difference between input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative gain or a second type phase shifter exhibiting a substantially constant relative gain of input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative phase difference.

8. An image rejection mixer comprising:

a phase shifting device for receiving first and second input signals and generating first and second phase shift output signals; and

a third adder for generating an output signal by adding the first and second phase shift output signals,

said phase shifting device including;

a first phase shifter for receiving an input signal and obtaining first and second intermediate phase shift signals having different phases;

a second phase shifter for obtaining first and second outputs by shifting phases of the first and second intermediate phase shift signals; and

a first adder for generating a first phase shift output signal by adding the first and second outputs from said second phase shifter;

a third phase shifter for receiving a second input signal out of phase with the first input signal and obtaining third and fourth intermediate phase shift signals;

a fourth phase shifter for obtaining third and fourth outputs by further shifting phases of the third and fourth intermediate phase shift signals; and

a second adder for generating a second phase shift output signal by adding the third and fourth outputs from said fourth phase shifter.

9. A mixer according to claim 8, wherein each of said first, second, third, and fourth phase shifters comprises either a first type phase shifter exhibiting a substantially constant relative phase difference between input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative gain or a second type phase shifter exhibiting a substantially constant relative gain of input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative phase difference.

10. An image rejection mixer comprising:

an oscillator for generating an oscillation signal having a predetermined frequency;

an oscillation circuit for receiving the oscillation signal from said oscillator and generating first and second phase shift output signals;

a first mixer for obtaining a first intermediate-frequency signal by mixing an input radio-frequency signal with the first phase shift output signal from said oscillation circuit;

a second mixer for obtaining a second intermediate-frequency signal by mixing the radio-frequency signal with the second phase shift output signal from said oscillation circuit;

a phase shifting device for receiving the first and second intermediate-frequency signals and generating first and second intermediate-frequency phase shift output signals; and

a fifth adder or generating an output signal by adding the first intermediate-frequency phase shift output signal with the second intermediate-frequency phase shift output signal,

said oscillation circuit including;

a first phase shifter for receiving an input signal and obtaining first and second intermediate phase shift signals having different phases;

a second phase shifter for obtaining first and second outputs by shifting phases of the first and second intermediate phase shift signals; and

a third phase shifter for obtaining third and fourth outputs by shifting phases of the first and second intermediate phase shift signals;

a first adder for generating a first phase shift output signal by adding the first and second outputs from said second phase shifter; and

a second adder for generating a second phase shift output signal by adding the third and fourth outputs from said third phase shifter, and

said phase shifting device including;

a fourth phase shifter for receiving the first intermediate-frequency signal and obtaining first and second intermediate phase shift signals having difference phases;

a fifth phase shifter for obtaining first and second outputs by further shifting phases of the first and second intermediate phase shift signals from said fourth phase shifter;

a third adder for generating a first intermediate-frequency phase shift output signal by adding the first and second outputs from said fifth phase shifter;

a sixth phase shifter for receiving the second intermediate-frequency signal and obtaining third and fourth phase shift signals having difference phases;

a seventh phase shifter for obtaining third and fourth outputs by further shifting phases of the third and fourth intermediate phase shift signals from said sixth phase shifter; and

a fourth adder for generating a second intermediate-frequency phase shift output signal by adding the third and fourth outputs from said seventh phase shifter.

11. A mixer according to claim 10, wherein each of said first, second, third, fourth, fifth, sixth, and seventh phase shifters comprises either a first type phase shifter exhibiting a substantially constant relative phase difference between input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative gain or a second type phase shifter exhibiting a substantially constant relative gain of input and output signals with respect to changes in input signal frequency in a wide range, and a frequency-dependent relative phase difference.

12. A phase shift circuit, comprising:

a first phase shifting circuit that inputs an input signal, phase shifts said input signal by a first phase angle to produce a first intermediate phase signal, and phase shifts said input signal by a second phase angle to produce a second intermediate phase signal, wherein said first phase angle is different from said second phase angle;

a second phase shifting circuit that generates a first output signal by phase shifting said first intermediate phase signal by a third phase angle and that generates a second output signal by phase shifting said second intermediate phase signal by a fourth phase angle, wherein said third phase angle is different from said fourth phase angle; and

a third phase shifting circuit that generates a third output signal by phase shifting said first intermediate phase signal by a fifth phase angle and that generates a fourth output signal by phase shifting said second intermediate phase signal by a sixth phase angle, wherein said fifth phase angle is different from said sixth phase angle.

13. The phase shift circuit as claimed in claim 12, further comprising:

a first adder that adds said first output signal and said second output signal to produce a first phase shift output signal; and

a second adder that adds said third output signal and said fourth output signal to produce a second phase shift output signal.

14. The phase shift circuit as claimed in claim 12, wherein said first phase angle substantially equals Ψ

and said second phase angle substantially equals −

Ψ

.

15. The phase shift circuit as claimed in claim 14, wherein said third phase angle substantially equals Ψ

and said fourth phase angle substantially equals Ψ

+θ

, and

wherein θ

is different from Ψ

.

16. The phase shift circuit as claimed in claim 15, wherein θ

substantially equals 90°

.

17. The phase shift circuit as claimed in claim 16, wherein Ψ

substantially equals 45°

.

18. The phase shift circuit as claimed in claim 15, wherein said fifth phase angle substantially equals Ψ

+θ and

said sixth phase angle substantially equals Ψ

+φ

, and

wherein θ

, Ψ

, and φ

are different from each other.

19. The phase shift circuit as claimed in claims 18, wherein θ

substantially equals 90° and

φ

substantially equals 180°

.

20. The phase shift circuit as claimed in claim 14, wherein said fifth phase angle substantially equals −

Ψ and

said sixth phase angle substantially equals Ψ

.

21. The phase shift circuit as claimed in claim 14, wherein said third phase angle substantially equals Ψ

and said fourth phase angle substantially equals −

Ψ

+φ

,

wherein Ψ and

φ

are different from each other.

22. The phase shift circuit as claimed in claim 21, wherein φ

substantially equals 180°

.

23. The phase shift circuit as claimed in claim 21, wherein said fifth phase angle substantially equals −

Ψ and

said sixth phase angle substantially equals Ψ

.

24. The phase shift circuit as claimed in claim 12, wherein said first phase angle substantially equals Ψ

and said second phase angle substantially equals Ψ

+θ

, and

wherein θ

is different from Ψ

.

25. The phase shift circuit as claimed in claim 24, wherein θ

substantially equals 90°

.

26. The phase shift circuit as claimed in claim 24, wherein Ψ

substantially equals 45°

.

27. The phase shift circuit as claimed in claim 24, wherein said third phase angle substantially equals Ψ

and said fourth phase angle substantially equals −

Ψ

.

28. The phase shift circuit as claimed in claim 24, wherein said fifth phase angle substantially equals −

Ψ

+φ and

said sixth phase angle substantially equals Ψ

, and

wherein θ

, Ψ

, and φ

are different from each other.

29. The phase shift circuit as claimed in claim 28, wherein said third phase angle substantially equals Ψ

and said fourth phase angle substantially equals −

Ψ

.

30. The phase shift circuit as claimed in claim 29, wherein θ

substantially equals 90° and

φ

substantially equals 180°

.

31. The phase shift circuit as claimed in claim 24, wherein said third phase angle substantially equals Ψ

and said fourth phase angle substantially equals Ψ

+θ

+φ

, and

wherein θ

, Ψ

, and φ

are different from each other.

32. The phase shift circuit as claimed in claim 31, wherein θ

substantially equals 90° and

φ

substantially equals 180°

.

33. The phase shift circuit as claimed in claim 24, wherein said fifth phase angle substantially equals Ψ

+θ and

said sixth phase angle substantially equals Ψ

.

34. The phase shift circuit as claimed in claim 33, wherein said third phase angle substantially equals Ψ

and said fourth phase angle substantially equals Ψ

+θ

+φ

, and

wherein θ

, Ψ

, and φ

are different from each other.

35. The phase shift circuit as claimed in claim 34, wherein θ

substantially equals 90° and

φ

substantially equals 180°

.

36. The phase shift circuit as claimed in claim 35, wherein Ψ

substantially equals 45°

.

37. A phase shift circuit, comprising:

a first phase shifting circuit that inputs a first input signal, phase shifts said first input signal by a first phase angle to produce a first intermediate phase signal, and phase shifts said first input signal by a second phase angle to produce a second intermediate phase signal, wherein said first phase angle is different from said second phase angle; and

a second phase shifting circuit that generates a first output signal by phase shifting said first intermediate phase signal by a third phase angle and that generates a second output signal by phase shifting said second intermediate phase signal by a fourth phase angle, wherein said third phase angle is different from said fourth phase angle.

38. The phase shift circuit as claimed in claim 37, further comprising:

a first adder that adds said first output signal and said second output signal to produce a first phase shift output signal.

39. The phase shift circuit as claimed in claim 37, further comprising:

a third phase shifting circuit that inputs a second input signal, phase shifts said second input signal by a fifth phase angle to produce a third intermediate phase signal, and phase shifts said second input signal by a sixth phase angle to produce a fourth intermediate phase signal, wherein said fifth phase angle is different from said sixth phase angle; and

a fourth phase shifting circuit that generates a third output signal by phase shifting said third intermediate phase signal by a seventh phase angle and that generates a fourth output signal by phase shifting said fourth intermediate phase signal by an eighth phase angle, wherein said seventh phase angle is different from said eight phase angle.

40. The phase shift circuit as claimed in claim 39, further comprising:

a first adder that adds said first output signal and said second output signal to produce a first phase shift output signal; and

a second adder that adds said third output signal and said fourth output signal to produce a second phase shift output signal.