Frequency doubling circuits, method, and systems including quadrature phase generators

• US 6,211,708 B1
• Filed: 06/28/1999
• Issued: 04/03/2001
• Est. Priority Date: 06/28/1999
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Klemmer, Nikolaus
• Primary Examiner(s): Tran, Toan
• Assistant Examiner(s): NGUYEN, LINH M
• Application Number:
  US09/344,932
• Time in Patent Office: 645 Days
• Field of Search: 327/238, 327/355, 327/356, 327/357, 327/116, 327/119, 327/122
• US Class Current: 327/122
• CPC Class Codes: H03B 21/01 by beating unmodulated signals of different frequencies
• CPC Class Codes: H03B 27/00 Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs
• CPC Class Codes: H03H 7/21 providing two or more phase shifted output signals, e.g. n-phase output

Abstract

A frequency doubling circuit includes a quadrature phase generator and a mixer coupled to the quadrature phase generator. The quadrature phase generator receives a reference signal having a reference frequency and generates first and second quadrature phase shifted signals having the reference frequency. The mixer receives the first and second quadrature phase shifted signals and generates an output signal having an output frequency twice that of the reference frequency. Related methods and communications devices are also discussed.

Claims

1. A frequency doubling circuit for doubling the frequency of a reference signal having a reference frequency, the frequency doubling circuit comprising:

a quadrature phase generator that receives the reference signal having the reference frequency and that generates first and second quadrature phase shifted signals having the reference frequency; and

a mixer coupled to the quadrature phase generator wherein the mixer receives the first and second quatrature phase shifted signals and generates an output signal having an output frequency twice that of the reference frequency.

2. A frequency doubling circuit according to claim 1:

wherein the quadrature phase generator receives the reference signal having the reference frequency and an inverse reference signal that is 180 degrees out of phase with respect to the reference signal and wherein the quadrature phase generator also generates third and fourth quadrature phase shifted signals so that the second, third, and fourth quadrature phase shifted signals are respectively shifted 90 degrees, 180 degrees, and 270 degrees with respect to the first quadrature phase shifted signal; and

wherein the mixer receives the four quadrature phase shifted signals to generate the output signal having the output frequency twice that of the reference frequency and to generate an inverse output signal that is 180 degrees out of phase with respect to the output signal.

3. A frequency doubling circuit according to claim 2 wherein the mixer comprises a multiplier.

4. A frequency doubling circuit according to claim 3 wherein the mixer comprises a Gilbert cell multiplier.

5. A frequency doubling circuit according to claim 1 wherein the mixer comprises an Exclusive-OR gate.

6. A frequency doubling circuit according to claim 1 wherein the mixer comprises a multiplier.

7. A frequency doubling circuit according to claim 6 wherein the mixer comprises a Gilbert cell multiplier.

8. A frequency doubling circuit according to claim 1 wherein the quadrature phase generator comprises a plurality of resistors and capacitors on an integrated circuit substrate wherein the resistors have a common resistance and wherein the capacitors have a common capacitance.

9. A frequency doubling circuit according to claim 1 wherein the quadrature phase shifted signals are shifted 90 degrees relative to each other.

10. A frequency doubling circuit according to claim 1 wherein the first quadrature phase shifted signal has a positive phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative phase shift relative to the reference signal.

11. A frequency doubling circuit according to claim 10 wherein the first quadrature phase shifted signal has a positive 45 degree phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative 45 degree phase shift relative to the reference signal.

12. A frequency doubling circuit according to claim 1 wherein the quadrature phase generator and the mixer are implemented on an integrated circuit substrate including a radio receiver.

13. A frequency doubling circuit according to claim 1 wherein the quadrature phase generator and the mixer are implemented on an integrated circuit substrate including a radio transmitter.

14. A frequency doubling method for doubling the frequency of a reference signal having a reference frequency, the method comprising the steps of:

generating first and second quadrature phase shifted signals having the reference frequency; and

generating an output signal having an output frequency twice that of the reference frequency responsive to the first and second quadrature phase shifted signals.

15. A method according to claim 14 further comprising the steps of:

generating third and fourth quadrature phase shifted signals so that the second, third, and fourth quadrature phase shifted signals are respectively shifted 90 degrees, 180 degrees, and 270 degrees with respect to the first quadrature phase shifted signal; and

generating an inverse output signal that is 180 degrees out of phase with respect to the output signal wherein the steps of generating the output and inverse output signals are responsive to the first, second, third, and fourth quadrature phase shifted signals.

16. A method according to claim 14 wherein the first and second quadrature phase shifted signals are shifted 90 degrees relative to each other.

17. A method according to claim 14 wherein the first quadrature phase shifted signal has a positive phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative phase shift relative to the reference signal.

18. A method according to claim 17 wherein the first quadrature phase shifted signal has a positive 45 degree phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative 45 degree phase shift relative to the reference signal.

19. A frequency doubling circuit for doubling the frequency of a reference signal having a reference frequency, the frequency doubling circuit comprising:

means for generating first and second quadrature phase shifted signals having the reference frequency responsive to the to the reference signal; and

means for generating an output signal having an output frequency twice that of the reference frequency responsive to the first and second quadrature phase shifted signals.

20. A frequency doubling circuit according to claim 19 further comprising:

means for generating third and fourth quadrature phase shifted signals so that the second, third, and fourth quadrature phase shifted signals are respectively shifted 90 degrees, 180 degrees, and 270 degrees with respect to the first quadrature phase shifted signal; and

wherein the means for generating the output signal comprises means for generating the output signal and for generating an inverse output signal that is 180 degrees out of phase with respect to the output signal responsive to the first, second, third, and fourth quadrature phase shifted signals.

21. A frequency doubling circuit according to claim 20 wherein the means for generating the output signal comprises a multiplier.

22. A frequency doubling circuit according to claim 21 wherein the means for generating the output signal comprises a Gilbert cell multiplier.

23. A frequency doubling circuit according to claim 19 wherein the means for generating the output signal comprises an Exclusive-OR gate.

24. A frequency doubling circuit according to claim 19 wherein the means for generating the output signal comprises a multiplier.

25. A frequency doubling circuit according to claim 24 wherein the emans for generating the output signal comprises a Gilbert cell multiplier.

26. A frequency doubling circuit according to claim 19 wherein the means for generating the first and second quadrature phase shifted signals comprises a plurality of resistors and capacitors on an integrated circuit substrate wherein the resistors have a common resistance and wherein the capacitors have a common capacitance.

27. A frequency doubling circuit according to claim 19 wherein the first and second quadrature phase shifted signals are shifted 90 degrees relative to each other.

28. A frequency doubling circuit according to claim 19 wherein the first quadrature phase shifted signal has a positive phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative phase shift relative to the reference signal.

29. A frequency doubling circuit according to claim 28 wherein the first quadrature phase shifted signal has a positive 45 degree phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative 45 degree phase shift relative to the reference signal.

30. A frequency doubling circuit according to claim 19 wherein the means for generating the first and second quadrature phase shifted signals and the means for generating the output signal are implemented on an integrated circuit substrate including at least a portion of a radio receiver.

31. A frequency doubling circuit according to claim 19 wherein the means for generating the first and second quadrature phase shifted signals and the means for generating the output signal are implemented on an integrated circuit substrate including a radio transmitter.

32. A radio communications device for transmitting and receiving radio communications, the radio communications device comprising:

a transmitter that transmits radio communications from the radio communications device;

a receiver that receives radio communications at the radio communications device;

a processor coupled to the transmitter and the receiver that controls transmission and reception of the radio communications; and

a frequency generation circuit coupled to the transmitter and the receiver wherein the frequency generation circuit generates a communications frequency signal for the transmitter and receiver, the frequency generation circuit comprising,

a reference signal generator that generates a reference signal having a reference signal,

a quadrature phase generator that receives the reference signal having the reference frequency and that generates first and second quadrature phase shifted signals having the reference frequency, and

a mixer coupled to the quadrature phase generator wherein the mixer receives the first and second quatrature phase shifted signals and generates the communications frequency signal having a communications frequency twice that of the reference frequency.

33. A radio communications device according to claim 32:

wherein the quadrature phase generator receives the reference signal having the reference frequency and an inverse reference signal that is 180 degrees out of phase with respect to the reference signal and wherein the quadrature phase generator also generates third and fourth quadrature phase shifted signals so that the second, third, and fourth quadrature phase shifted signals are respectively shifted 90 degrees, 180 degrees, and 270 degrees with respect to the first quadrature phase shifted signal; and

wherein the mixer receives the four quadrature phase shifted signals to generate the output signal having the output frequency twice that of the reference frequency and to generate an inverse output signal that is 180 degrees out of phase with respect to the output signal.

34. A radio communications device according to claim 33 wherein the mixer comprises a multiplier.

35. A radio communications device according to claim 34 wherein the mixer comprises a Gilbert cell multiplier.

36. A radio communications device according to claim 32 wherein the quadrature phase generator comprises a plurality of resistors and capacitors on an integrated circuit substrate wherein the resistors have a common resistance and wherein the capacitors have a common capacitance.

37. A radio communications device according to claim 32 wherein the quadrature phase shifted signals are shifted 90 degrees relative to each other.

38. A radio communications device according to claim 32 wherein the first quadrature phase shifted signal has a positive phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative phase shift relative to the reference signal.

39. A radio communications device according to claim 38 wherein the first quadrature phase shifted signal has a positive 45 degree phase shift relative to the reference signal, and wherein the second quadrature phase shifted signal has a negative 45 degree phase shift relative to the reference signal.

40. A radio communications device according to claim 32 wherein the quadrature phase generator and the mixer are implemented on an integrated circuit substrate including at least a portion of the receiver.

41. A radio communications device according to claim 32 wherein the quadrature phase generator and the mixer are implemented on an integrated circuit substrate including at least a portion of the transmitter.

42. A radio communications device according to claim 32 wherein the reference signal generator comprises a voltage controlled oscillator.