Transmitter method, apparatus, and frequency plan for minimizing spurious energy

US 6,868,261 B2
Filed: 03/29/2002
Issued: 03/15/2005
Est. Priority Date: 09/05/2001
Status: Expired due to Fees

First Claim

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1. A transmitter apparatus, comprising:

a local oscillator (LO) generator that generates an LO signal having a tunable frequency f_LO1; and

a phase-locked-loop (PLL) that generates an output signal that is phase-locked to a reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands responsive to the LO signal, the PLL including a feedback path for generating a feedback signal having a desired frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in at least one of the first and second alternative frequency bands, and the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in at least one of the first and second alternative frequency bands.

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Abstract

A translational-loop transmitter includes a local oscillator (LO) generator for generating first and second LO signals, a modulator for generating a modulated reference signal using the second LO signal, and an offset phase-locked-loop (PLL) for phase-locking an output signal to the reference signal, and for tuning the output signal in accordance with the first LO signal. The PLL includes an offset mixer in a feedback path of the PLL, and operates in accordance with a frequency plan that minimizes the effects of on- and off-channel spurs at the output of the offset mixer.

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40 Claims

1. A transmitter apparatus, comprising:
- a local oscillator (LO) generator that generates an LO signal having a tunable frequency f_LO1; and
  
  a phase-locked-loop (PLL) that generates an output signal that is phase-locked to a reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands responsive to the LO signal, the PLL including a feedback path for generating a feedback signal having a desired frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in at least one of the first and second alternative frequency bands, and the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in at least one of the first and second alternative frequency bands.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- - 2. The apparatus of claim 1, wherein:
    - the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands; and
      
      the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands.
  - 3. The apparatus of claim 1, wherein the frequency f_FBrepresents a difference between frequency f_LO1and frequency f_TX.
  - 4. The apparatus of claim 1, wherein the LO generator includes:
    - a source oscillator for generating a source signal having a frequency f_SLO; and
      
      a frequency divider circuit to produce the LO signal from the source signal, wherein a ratio of the frequency f_SLOwhen the frequency f_TXis in the first frequency band to the frequency f_SLOwhen the frequency f_TXis in the second frequency band is approximately 2;
      
      1.
  - 5. The apparatus of claim 4, wherein the LO generator includes:
    - a source oscillator for generating a source signal having a frequency f_SLO; and
      
      a frequency divider circuit to produce the LO signal from the source signal, wherein the frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen the frequency f_TXis in the first frequency band, and the frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen the frequency f_TXis in the second frequency band.
  - 6. The apparatus of claim 5, wherein the frequency f_TXis tunable within a third frequency band, and when the frequency f_TXis in the third frequency bandthe frequency f_SLOis approximately equal to 7/3 the frequency f_TX, the frequency f_LO1is approximately equal to 7/6 the frequency f_TX, and the frequency f_FBis approximately equal to 1/6 the frequency f_TX.
  - 7. The apparatus of claim 1, wherein the frequency f_FBis a first intermediate frequency when the frequency f_TXis in the first frequency band and a second intermediate frequency separated from the first intermediate frequency when the frequency f_TXis in the second frequency band, the PLL feedback path comprising:
    - an offset mixer for generating the feedback signal having the desired frequency f_FBresponsive to the frequencies f_TXand f_LO1;
      
      a first filter, following the offset mixer, that passes the first intermediate frequency and rejects first spurious energy offset in frequency from the first intermediate frequency when the frequency f_TXis in the first frequency band; and
      
      a second filter, following the offset mixer, that passes the second intermediate frequency and rejects second spurious energy offset in frequency from the second intermediate frequency when the frequency f_TXis in the second frequency band.
  - 8. The apparatus of claim 7, wherein the combination of frequencies f_LO1and f_TXcausesthe first spurious energy to be offset in frequency from the first intermediate frequency by at least an integer multiple of the first intermediate frequency, and the second spurious energy to be offset in frequency from the second intermediate frequency by at least an integer multiple of the second intermediate frequency.
  - 9. The apparatus of claim 7, wherein the first and second bandpass filters are each adapted to produce a respective filtered feedback signal, the PLL further including:
    - a phase or frequency detector that derives an error signal responsive to the reference signal and a respective one of the filtered feedback signals;
      
      a control signal deriving circuit following the phase or frequency detector that derives a control signal from the error signal; and
      
      a Voltage Controlled Oscillator (VCO), following the control signal deriving circuit, that generates the phase-locked output signal responsive to the control signal.
  - 10. The apparatus of claim 1, wherein:
    - the first frequency band extends approximately between 880 MHz and 915 MHz; and
      
      the second frequency band extends between one of the following, approximately between 1710 MHz and 1785 MHz, or approximately between 1850 MHz and 1910 MHz.
  - 11. The apparatus of claim 1, wherein the frequency f_TXis tunable within a third frequency band, andthe first frequency band extends approximately between 880 MHz and 915 MHz, the second frequency band extends approximately between 1710 MHz and 1785 MHz, and the third frequency band extends approximately between 1850 MHz and 1910 MHz.
  - 12. The apparatus of claim 1, wherein the reference signal and the output signal each include at least one of a phase modulated signal component and a frequency modulated signal component.
  - 13. The apparatus of claim 12, wherein the LO generator is adapted to generate a second LO signal, the apparatus further comprising:
    - a modulator that modulates the second LO signal with a baseband signal to produce the reference signal such that the reference signal has a frequency f_MODsubstantially equal to the feedback frequency f_FB.

14. A transmitter apparatus, comprising:
- a source oscillator for generating a source signal having a frequency f_SLO;
  
  a frequency divider circuit to produce, from the source signal, a local oscillator (LO) signal having a tunable frequency f_LO1; and
  
  a phase-locked-loop (PLL) that generates an output signal that is phase-locked to a reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands responsive to the LO signal, the PLL including an offset mixer in a feedback path of the PLL for generating a feedback signal having a frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen the frequency f_TXis in the first frequency band, the frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen the frequency f_TXis in the second frequency band, the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands, and the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands.
- View Dependent Claims (15, 16)
- - 15. The apparatus of claim 14, wherein the frequency f_TXis tunable within a third alternative frequency band, and when the frequency f_TXis in the third frequency bandthe frequency f_SLOis approximately equal to 7/3 the frequency f_TXthe frequency f_LO1is approximately equal to 7/6 the frequency f_TX, and the frequency f_FBis approximately equal to 1/6 the frequency f_TX.
  - 16. The apparatus of claim 14, wherein:
    - the first frequency band extends approximately between 880 MHz and 915 MHz;
      
      the second frequency band extends approximately between 1710 MHz and 1785 MHz; and
      
      the third frequency band extends approximately between 1850 MHz and 1910 MHz.

17. A transmitter apparatus, comprising:
- a local oscillator (LO) generator that generates an LO signal having a frequency f_LO1; and
  
  a phase-locked-loop (PLL) that generates an output signal that is phase-locked to a reference signal, the output signal having a frequency f_TXtunable within first and second alternative frequency bands responsive to the LO signal, the first frequency band extending approximately between 880 MHz and 915 MHz, the second frequency band extending either approximately between 1710 MHz and 1785 MHz or approximately between 1850 MHz and 1910 MHz, the PLL including an offset mixer in a feedback path of the PLL for generating a feedback signal having a frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands, and the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands.
- View Dependent Claims (18, 19)
- - 18. The apparatus of claim 17, wherein the frequency f_TXis tunable within a third alternative frequency band, the third frequency band extending eitherapproximately between 1710 MHz and 1785 MHz when the second frequency band extends approximately between 1850 MHz and 1910 MHz, or approximately between 1850 MHz and 1910 MHz when the second frequency band extends approximately between 1710 MHz and 1785 MHz, and when frequency f_TXis in the third frequency band, the frequency f_SLOis approximately equal to 7/3 the frequency f_TX, the frequency f_LO1is approximately equal to 7/6 the frequency f_TX, and the frequency f_FBis approximately equal to 1/6 the frequency f_TX.
  - 19. The apparatus of claim 17, wherein the LO generator includes:
    - a source oscillator for generating a source signal having a frequency f_SLO; and
      
      a frequency divider circuit to produce the LO signal from the source signal, wherein the frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen the frequency f_TXis in the first frequency band, and the frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen the frequency f_TXis in the second frequency band.

20. A transmit apparatus, comprising:
- a source oscillator for generating a source signal having a frequency f_SLO;
  
  a frequency divider circuit to produce, from the source signal, a local oscillator (LO) signal having a tunable frequency; and
  
  a phase-locked-loop (PLL) that generates an output signal that is phase-locked to a reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands responsive to the LO signal, the PLL including an offset mixer in a feedback path of the PLL for generating a feedback signal having a frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen the frequency f_TXis in the first frequency band, and the frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen the frequency f_TXis in the second frequency band.

21. A transmitter apparatus, comprising:
- a source oscillator that generates a source signal having a frequency f_SLO;
  
  divider circuits for generating from the source signal a first local oscillator (LO) signal having a frequency f_LO1and a second LO signal having a frequency f_LO2;
  
  a modulator for generating a modulated reference signal having a frequency f_MODbased on the second LO signal;
  
  a phase-locked-loop (PLL) that generates an output signal that is phase-locked to the reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands responsive to the first LO signal, the PLL including an offset mixer in a feedback path of the PLL for generating a feedback signal having a frequency f_FBresponsive to the frequencies f_TXand f_LO1, the transmitter apparatus being configured to operate in accordance with a frequency plan, wherein the frequency plan specifies that frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen frequency f_TXis in the first frequency band, frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen frequency f_TXis in the second frequency band, frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen frequency f_TXis in each of the first and second alternative frequency bands, frequency f_MODis approximately equal to 1/6 the frequency f_TXwhen frequency f_TXis in each of the first and second alternative frequency bands, frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen frequency f_TXis in each of the first and second alternative frequency bands, and frequency f_LO2is approximately equal to 1/6 the frequency f_TXwhen frequency f_TXis in each of the first and second alternative frequency bands.

22. A method, comprising:
- (a) generating a local oscillator (LO) signal having a tunable frequency f_LO1; and
  
  (b) phase-locking an output signal to a reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands, said phase-locking including producing a feedback signal having a desired frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in at least one of the first and second alternative frequency bands, and the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in at least one of the first and second alternative frequency bands.
- View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
- - 23. The method of claim 22, wherein:
    - the frequency f_FBis approximately equal to ⅙
      
      the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands; and
      
      the frequency f_LO1is approximately equal to {fraction (7/6)} the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands.
  - 24. The method of claim 22, wherein step (a) includes:
    - generating a source signal having a frequency f_SLO; and
      
      frequency dividing the source signal to produce the LO signal, wherein a ratio of the frequency f_SLOwhen the frequency f_TXis in the first frequency band to the frequency f_SLOwhen the frequency f_TXis in the second frequency band is approximately 2;
      
      1.
  - 25. The method of claim 24, whereinthe frequency f_SLOis approximately equal to {fraction (14/3)} the frequency f_TXwhen the frequency f_TXis in the first frequency band, and the frequency f_SLOis approximately equal to {fraction (7/3)} the frequency f_TXwhen the frequency f_TXis in the second frequency band.
  - 26. The method of claim 25, wherein the frequency f_TXis tunable within a third alternative frequency band, and when the frequency f_TXis in the third frequency bandthe frequency f_SLOis approximately equal to {fraction (7/3)} the frequency f_TX, the frequency f_LO1is approximately equal to {fraction (7/6)} the frequency f_TX, and the frequency f_FBis approximately equal to ⅙
    - the frequency f_TX.
  - 27. The method of claim 22, wherein the frequency f_FBis a first intermediate frequency when the frequency f_TXis in the first frequency band and a second intermediate frequency separated from the first intermediate frequency when the frequency f_TXis in the second frequency band, and wherein step (b) further comprises:
    - producing the feedback signal by frequency-mixing the output signal with the LO signal;
      
      filtering the feedback signal to pass the first intermediate frequency and reject first spurious energy offset in frequency from the first intermediate frequency when the frequency f_TXis in the first frequency band; and
      
      filtering the feedback signal to pass the second intermediate frequency and reject second spurious energy offset in frequency from the second intermediate frequency when the frequency f_TXis in the second frequency band.
  - 28. The method of claim 27, wherein said frequency-mixing comprises generating the frequency f_FBas a difference between the frequency f_LO1and the frequency F_TX.
  - 29. The method of claim 27, wherein each said filtering step produces a respective filtered feedback signal, and wherein step (b) further comprises:
    - deriving an error signal responsive to the reference signal and a respective one of the filtered feedback signals;
      
      deriving a control signal from the error signal; and
      
      generating the phase-locked output signal responsive to the control signal.
  - 30. The method of claim 22, wherein:
    - the first frequency band extends approximately between 880 MHz and 915 MHz; and
      
      the second frequency band extends between one of the following, approximately between 1710 MHz and 1785 MHz, or approximately between 1850 MHz and 1910 MHz.
  - 31. The method of claim 22, wherein the frequency f_TXis tunable within a third alternative frequency band, andthe first frequency band extends approximately between 880 MHz and 915 MHz, the second frequency band extends approximately between 1710 MHz and 1785 MHz, and the third frequency band extends approximately between 1850 MHz and 1910 MHz.
  - 32. The method of claim 22, wherein the reference signal and the output signal each include at least one of a phase modulated component and a frequency modulated component.
  - 33. The method of claim 32, further comprising:
    - generating a second LO signal; and
      
      producing the reference signal from a baseband signal using the second LO signal.

34. A method, comprising:
- generating a source signal having a tunable frequency f_SLO;
  
  producing a local oscillator (LO) signal having a tunable frequency f_LO1by frequency-dividing down the frequency f_SLOto the frequency f_LO1; and
  
  phase-locking an output signal to a reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands responsive to the LO signal, said phase-locking including frequency-mixing the output signal with the LO signal to produce a feedback signal having a frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen the frequency f_TXis in the first frequency band, the frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen the frequency f_TXis in the second frequency band, the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands, and the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands.
- View Dependent Claims (35, 36)
- - 35. The method of claim 34, wherein the frequency f_TXis tunable within a third alternative frequency band, and when the frequency f_TXis in the third frequency bandthe frequency f_SLOis approximately equal to 7/3 the frequency f_TXthe frequency f_LO1is approximately equal to 7/6 the frequency f_TX, and the frequency f_FBis approximately equal to 1/6 the frequency f_TX.
  - 36. The method of claim 34, wherein:
    - the first frequency band extends approximately between 880 MHz and 915 MHz;
      
      the second frequency band extends approximately between 1710 MHz and 1785 MHz; and
      
      the third frequency band extends approximately between 1850 MHz and 1910 MHz.

37. A method, comprising:
- (a) generating a local oscillator (LO) signal having a frequency f_LO1; and
  
  (b) phase-locking an output signal to a reference signal, the output signal having a frequency f_TXtunable within first and second alternative frequency bands responsive to the LO signal, the first frequency band extending approximately between 880 MHz and 915 MHz, the second frequency band extending either approximately between 1710 MHz and 1785 MHz or approximately between 1850 MHz and 1910 MHz, said phase-locking including frequency-mixing the output signal with the LO signal to produce a feedback signal having a frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_LO1is approximately equal to 7/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands, and the frequency f_FBis approximately equal to 1/6 the frequency f_TXwhen the frequency f_TXis in each of the first and second alternative frequency bands.
- View Dependent Claims (38, 39)
- - 38. The method of claim 37, wherein the frequency f_TXis tunable within a third alternative frequency band, the third frequency band extending eitherapproximately between 1710 MHz and 1785 MHz when the second frequency band extends approximately between 1850 MHz and 1910 MHz, or approximately between 1850 MHz and 1910 MHz when the second frequency band extends approximately between 1710 MHz and 1785 MHz, and when frequency f_TXis in the third frequency band, the frequency f_SLOis approximately equal to 7/3 the frequency f_TX, the frequency f_LO1is approximately equal to 7/6 the frequency f_TX, and the frequency f_FBis approximately equal to 1/6 the frequency f_TX.
  - 39. The method of claim 37, wherein step (a) includes:
    - generating a source signal having a frequency f_SLO; and
      
      frequency-dividing the source signal to produce the LO signal, wherein the frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen the frequency f_TXis in the first frequency band, and the frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen the frequency f_TXis in the second frequency band.

40. A method, comprising:
- generating a source signal having a tunable frequency f_SLO;
  
  frequency dividing the source signal to produce a local oscillator (LO) signal having a tunable frequency; and
  
  phase-locking an output signal to a reference signal, the output signal having a frequency f_TXtunable within at least first and second alternative frequency bands responsive to the LO signal, said phase-locking including frequency-mixing the output signal with the LO signal to produce a feedback signal having a frequency f_FBresponsive to the frequencies f_TXand f_LO1, wherein the frequency f_SLOis approximately equal to 14/3 the frequency f_TXwhen the frequency f_TXis in the first frequency band, and the frequency f_SLOis approximately equal to 7/3 the frequency f_TXwhen the frequency f_TXis in the second frequency band.

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Current Assignee
Avago Technologies General IP PTE Limited (Broadcom, Inc.)
Original Assignee
Broadcom Corporation (Broadcom, Inc.)
Inventors
Shi, Hong, Carr, Frank
Primary Examiner(s)
Trinh, Sonny

Application Number

US10/108,986
Publication Number

US 20030092414A1
Time in Patent Office

1,082 Days
Field of Search

455/260, 455/259, 455/255, 455/73, 455/76, 455/550.1, 455/91, 455/168.1, 455/552.1, 455/501, 455/432.1, 455/63.1, 455/67.13, 455/114.2, 327/147, 327/156, 331/1.R, 331/10, 331/16, 331/17, 331/25
US Class Current

455/114.2
CPC Class Codes

H04B 1/0475 with means for limiting noi...

H04B 2001/0491 with frequency synthesizers...

Transmitter method, apparatus, and frequency plan for minimizing spurious energy

First Claim

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Abstract

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40 Claims

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Transmitter method, apparatus, and frequency plan for minimizing spurious energy

First Claim

5 Assignments

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Accused Products

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Abstract

28 Citations

40 Claims

Specification

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