METHOD AND CIRCUIT FOR CALIBRATING ANALOG CIRCUIT COMPONENTS

• US 20100178891A1
• Filed: 07/08/2009
• Published: 07/15/2010
• Est. Priority Date: 01/09/2009
• Status: Abandoned Application

• Current Assignee: Ralink Technology Corporation (MediaTek, Inc.)
• Original Assignee: Ralink Technology Corporation (MediaTek, Inc.)
• Inventors: TU, Yung Szu, LIAO, Yen Chin, CHEN, Jiunn Tsair, WEN, Chun Hsien
• Application Number:
  US12/499,587
• Publication Number:
  US 20100178891A1
• Time in Patent Office: Days
• US Class Current: 455/226.100
• CPC Class Codes: H04B 17/10 of transmitters
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements

Abstract

A method for calibrating an analog circuit component comprises the steps of: generating a first signal with a baseband frequency; generating a second signal by processing the first signal via the analog component to be calibrated; generating a third signal by processing the second signal via a power amplifier, wherein the power amplifier operates in a nonlinear region; generating a fourth signal by processing the third signal via a low-pass filter; and defining the adjustment for the In-phase-Quadrature-phase imbalance (IQ imbalance) of the analog component and then re-executing the step of generating the first signal, if the fourth signal shows an IQ imbalance mismatch.

Claims

1. A method for calibrating an analog component, comprising the steps of:

generating a first signal with a baseband frequency;

passing the first signal through the analog component to be calibrated to generate a second signal;

passing the second signal through a power amplifier to generate a third signal, wherein the power amplifier operates in a nonlinear region;

filtering out a high-frequency component of the third signal to generate a fourth signal with a baseband frequency; and

adjusting calibration parameters corresponding to an In-phase-Quadrature-phase imbalance (IQ imbalance) if the fourth signal shows the IQ imbalance, and re-executing the step of generating a first signal according to the calibration parameters.

2. The method of claim 1, wherein the first signal is a sine wave signal.

3. The method of claim 1, wherein the analog component to be calibrated comprises a low-pass filter, a variable gain amplifier and a mixer.

4. The method of claim 1, wherein the step of filtering the third signal is realized by an envelope detector.

5. The method of claim 1, wherein the calibration parameters corresponding to the IQ imbalance comprises a gain calibration parameter and a phase calibration parameter.

6. The method of claim 1, further comprising the steps of:

generating a calibration parameter for a nonlinearity of the power amplifier according to the first signal and the fourth signal if the fourth signal does not show the IQ imbalance.

7. The method of claim 6, wherein the step of generating a calibration parameter for the nonlinearity of the power amplifier is calculated by a least mean square algorithm.

8. The method of claim 6, wherein the step of generating a calibration parameter for the nonlinearity of the power amplifier is realized by a look-up table.

9. A circuit for calibrating an analog component, comprising:

a power amplifier operating in a nonlinear region and configured to amplify an output signal of the analog component to be calibrated;

a low-pass filter configured to filter an output signal of the power amplifier;

an analog-to-digital converter configured to convert an output signal of the low-pass filter; and

a spectrum analysis unit configured to analyze an output signal of the analog-to-digital converter.

10. The circuit of claim 9, wherein the analog component to be calibrated comprises a low-pass filter, a variable gain amplifier and a mixer.

11. The circuit of claim 9, further comprising:

a pre-distortion circuit configured to adjust an input signal to compensate a nonlinearity effect of the power amplifier; and

a calibration calculation circuit configured to adjust compensation parameters of the pre-distortion circuit according to the output signal of the power amplifier.

12. The circuit of claim 11, wherein the calibration calculation circuit utilizes a least mean square algorithm.

13. The circuit of claim 11, wherein the pre-distortion circuit is realized by a look-up table.

14. A method for calibrating a wireless transceiver, comprising the steps of:

generating a first signal with a baseband frequency;

passing the first signal through analog component to be calibrated to generate a second signal;

passing the second signal through a power amplifier to generate a third signal, wherein the power amplifier operates in a nonlinear region;

filtering out a high-frequency component of the third signal to generate a fourth signal with a baseband frequency; and

emitting the fourth signal on a carrier frequency, adjusting calibration parameters corresponding to an In-phase-Quadrature-phase imbalance (IQ imbalance) if the fourth signal shows the IQ imbalance, and re-executing the step of generating a first signal according to the calibration parameters.

15. The method of claim 14, wherein the first signal is a sine wave signal.

16. The method of claim 14, wherein the analog component to be calibrated comprises a low-pass filter, a variable gain amplifier and a mixer.

17. The method of claim 14, wherein the calibration parameters corresponding to the IQ imbalance comprise a gain calibration parameter and a phase calibration parameter.

18. A wireless transceiver, comprising:

a power amplifier operating in a nonlinear region configured to amplify an output signal of analog component to be calibrated;

a low-pass filter configured to filter an output signal of the power amplifier;

an analog-to-digital converter configured to convert an output signal of the low-pass filter;

a spectrum analysis unit configured to analyze an output signal of the analog-to-digital converter; and

an antenna configured to emit an output signal of the power amplifier on a carrier frequency.

19. The wireless transceiver of claim 18, wherein the analog component to be calibrated comprises a low-pass filter, a variable gain amplifier and a mixer.