QUADRATURE ERROR CORRECTION USING POLYNOMINAL MODELS IN TONE CALIBRATION

• US 20140273902A1
• Filed: 05/20/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: An, Wei, Schubert, Richard P., Stein, Yosef
• Granted Patent: US 9,281,907 B2
• Time in Patent Office: Days
• US Class Current: 455/226.1
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/391 Modelling the propagation channel

Abstract

One example embodiment provides a system, apparatus, and method for using polynomial models in tone calibration for quadrature error correction in I/Q receivers. In one example embodiment, method for calibrating an I/Q receiver is provided and includes receiving a first mismatch parameter indicating a mismatch between I and Q channels of the I/Q receiver; and estimating a second mismatch parameter from the first mismatch parameter using a polynomial model.

Claims

1. A method for calibrating an I/Q receiver, comprising:

receiving a first mismatch parameter indicating a mismatch between I and Q channels of the I/Q receiver; and

estimating a second mismatch parameter from the first mismatch parameter using a polynomial model.

2. The method of claim 1, wherein the estimating comprises applying a third order polynomial to estimate the second mismatch parameter.

3. The method of claim 2, wherein the estimating comprises applying a fourth order polynomial to estimate the second mismatch parameter.

4. The method of claim 1, wherein the first mismatch parameter comprises a first plurality of frequency dependent mismatch parameters at frequencies over a test spectrum, and wherein the estimating comprises estimating a second plurality of frequency dependent mismatch parameters over negative and positive frequency pairs in the test spectrum.

5. The method of claim 1, wherein the estimating comprises minimizing a matrix using least squared error (LSE) calculations.

6. The method of claim 1, wherein the first mismatch parameter comprises a total gain mismatch and a total phase mismatch.

7. The method of claim 1, further comprising:

performing tone calibration by generating N tone signals over a test spectrum;

inputting the tone signals to the I/Q receiver;

performing tone calibration in a tone calibration estimator to generate the first mismatch parameter; and

inputting the first mismatch parameter to the polynomial calibration estimator.

8. The method of claim 7, wherein the estimating a second mismatch parameter comprises estimating a gain mismatch parameter and a phase mismatch parameter for each frequency of the tone signals.

9. The method of claim 7, wherein the estimating a second mismatch parameter comprises estimating a parameter mismatch over negative and positive frequency pairs in the test spectrum.

10. An apparatus for calibrating an I/Q receiver, the apparatus comprising:

a polynomial estimator configured to;

receive a first mismatch parameter, wherein the first mismatch parameter estimation indicates a mismatch between I and Q channels of the I/Q receiver; and

estimate a second mismatch parameter from the first mismatch parameter estimation using a polynomial model.

11. The apparatus of claim 10, wherein the polynomial estimator estimates the second mismatch parameter from the first mismatch parameter by applying a third order polynomial.

12. The apparatus of claim 11, wherein the polynomial estimator estimates the second mismatch parameter from the first mismatch parameter by applying a fourth order polynomial.

13. The apparatus of claim 10, wherein the first mismatch parameter comprises a first plurality of frequency dependent mismatch parameters at frequencies of a test spectrum, and wherein the polynomial estimator estimates the second plurality of frequency dependent mismatch parameters over negative and positive frequency pairs of the test spectrum.

14. The apparatus of claim 10, wherein the polynomial estimator estimates the second mismatch parameter using a polynomial with a matrix and uses least squared error (LSE) calculations.

15. The apparatus of claim 10, wherein the first mismatch parameter received by the polynomial estimator comprises a total gain mismatch and a total phase mismatch.

16. The apparatus of claim 10, further comprising:

a tone generator configured to generate N tone signals over a test frequency spectrum and input the tone signals into the I/Q receiver analog paths;

a transform block coupled to an end of a particular analog path, the transform block for transforming the signals received at the end of the particular analog path from a time domain signal to a frequency domain signal and output the frequency domain signal; and

a tone calibration estimator coupled to the transform block and the polynomial estimator, the tone calibration estimator configured to receive the frequency domain signal from the transform block, perform tone calibration on a frequency domain test signal to generate the first mismatch parameter and input the first mismatch parameter estimation to the polynomial estimator.

17. The apparatus of claim 16, wherein the second mismatch parameter comprises a total gain mismatch parameter and a total phase mismatch parameter for each frequency of the N tone signals.

18. The apparatus of claim 16, wherein the first parameter comprises a plurality of frequency dependent mismatch parameters at frequencies over the test frequency spectrum, and wherein the polynomial estimator estimates the second frequency dependent mismatch parameter over negative and positive frequency pairs in the test frequency spectrum.

19. An apparatus for calibrating an I/Q receiver, comprising:

a tone calibration estimator configured to inject test tones at frequencies within a test spectrum into the I/Q receiver, estimate a first set of mismatch parameters comprising a total gain mismatch parameter and a total phase mismatch parameter, and output the first set of mismatch parameters.

a polynomial calibration estimator coupled to the tone calibration estimator, the polynomial calibration estimator configured to receive the first set of mismatch parameters from the tone calibration estimator and estimate a second set of mismatch parameters from the first set of mismatch parameters using a polynomial model, the second set of mismatch parameters comprising a frequency-dependent gain mismatch parameter, a frequency-dependent phase mismatch parameter, and a frequency-independent phase mismatch parameter.

20. The apparatus of claim 19, wherein the polynomial calibration estimator estimates the second set of mismatch parameters over negative and positive frequency pairs in the test spectrum.