Method and apparatus of compensating imbalance of a modulator

• US 20040032913A1
• Filed: 08/14/2002
• Published: 02/19/2004
• Est. Priority Date: 08/14/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Dinur, Nati
• Granted Patent: US 7,092,454 B2
• Time in Patent Office: Days
• US Class Current: 375/298
• CPC Class Codes: H03C 1/06 Modifications of modulator to reduce distortion, e.g. by feedback, and clearly applicable to more than one type of modulator
• CPC Class Codes: H03C 3/406 using a feedback loop containing mixers or demodulators
• CPC Class Codes: H03D 3/009 Compensating quadrature phase or amplitude imbalances

Abstract

Briefly, a method and apparatus to compensate an imbalance of a modulator by providing calibration parameters to a calibration network. The modulator may receive a pair of predetermined sinusoidal in-phase and quadrature signals and output a distorted modulated signal. A processor may process spectral parameters at first and second harmonics of a detected envelope signal of the distorted modulated signal may generate the calibration parameters.

Claims

1. An apparatus comprising:

a modulator to generate a distorted modulated signal based on a pair of calibration signals;

a detector to detect an envelope of the distorted modulated signal; and

a processor to generate calibration parameters able to compensate an imbalance of the modulator.

2. The apparatus of claim 1, further comprising:

a calibration network able to compensate a modulator imbalance by manipulating the calibration parameters.

3. The apparatus of claim 1 wherein the pair of calibration signals comprises:

a pair of sinusoidal signals at predetermined frequencies and predetermined amplitudes.

4. The apparatus of claim 1, further comprising:

a measuring module to measure a spectral component at first and second harmonics of the envelope signal.

5. The apparatus of claim 1, wherein the modulator comprises a quadrature modulator.

6. The apparatus of claim 1, further comprising:

an amplifier to amplify the compensated modulated signal.

7. A method comprising:

providing calibration parameters to a calibration network by modulating a pair of predetermined sinusoidal signals and measuring spectral parameters at first and second harmonics of a detected envelope signal of a modulated signal.

8. The method of claim 7 wherein providing calibration parameters comprises generating a first set of calibration parameters that result in a measured value of substantially zero of the spectral parameter of the first harmonic.

9. The method of claim 7 wherein providing calibration parameters comprises generating a second set of calibration parameters that result in a value of the spectral parameter of the second harmonic of the detected envelope signal substantially equal to an electric power of a transmitted signal when sending substantially the same calibration signal over one of an in-phase branch and a quadrature branch of the calibration network.

10. The method of claim 9 wherein, generating a second set of parameters comprises generating the second set of parameters that result in a value of the spectral parameter of the second harmonic of the detected envelope signal substantially equal to an electric power of a transmitted signal when sending substantially the same calibration signals over the in-phase branch and the quadrature branch of the calibration network, and when sending opposite calibration signals over the in-phase branch and the quadrature branch.

11. An apparatus comprising:

a modulator to generate a distorted modulated signal according to a pair of calibration signals;

a processor to generate calibration parameters able to compensate an imbalance of the modulator; and

a dipole antenna to transmit a modulated signal compensated by the calibration parameters.

12. The apparatus of claim 11, further comprising:

a detector to detect an envelop of the distorted modulated signal.

13. The apparatus of claim 11, further comprising:

a calibration network able to compensate the modulator imbalance by manipulating the calibration parameters.

14. The apparatus of claim 11 wherein, the pair of calibration signals comprises:

a pair of sinusoidal signals having predetermined frequencies and predetermined amplitudes.

15. The apparatus of claim 11, further comprising:

a measuring module to measure a spectral component at first and second harmonic of the envelope signal.

16. The apparatus of claim 11, wherein the modulator comprises a quadrature modulator.

17. The apparatus of claim 11, further comprising:

a power amplifier to amplify the compensated modulated signal.

18. An article comprising:

a storage medium, having stored thereon instructions, that when executed, result in;

providing calibration parameters to a calibration network by modulating a pair of predetermined sinusoidal signals and measuring spectral parameters at first and second harmonics of a detected envelope signal of a modulated signal.

19. The article of claim 18, wherein the instructions of providing, that when executed, further result in:

generating a first set of calibration parameters that result in a measured value of substantially zero of the spectral parameter of the first harmonic.

20. The article of claim 18, wherein the instructions of providing, that when executed, further result in:

generating a second set of calibration parameters that result in a value of the spectral parameter of the second harmonic of the detected envelope signal substantially equal to an electric power of a transmitted signal when sending substantially the same calibration signal over one of an in-phase branch and a quadrature branch of the calibration network.

21. The article of claim 20, wherein the instructions of generating, that when executed, further result in:

generating the second set of parameters that result in a value of the spectral parameter of the second harmonic of the detected envelope signal substantially equal to an electric power of a transmitted signal when sending substantially the same calibration signals over the in-phase branch and the quadrature branch of the calibration network, and when sending opposite calibration signals over the in-phase branch and the quadrature branch.