Vector calibration system

Abstract

Among other things, calibration of a signal processing system is disclosed to minimize vector mismatch between signals frequency-translated from an RF signal and conveyed along a plurality of signal paths of the signal processing system. A calibration signal having a plurality of tones is coupled to the signal processing system such that it is frequency translated. The frequency-translated calibration signal is sampled along a first signal path of the signal processing system to obtain a first set of observed samples. It is also sampled along a second signal path of the system to obtain a second set of observed samples. The first set of observed samples is filtered with an adaptive filter having a set of adaptable coefficients to obtain a set of filtered samples. The coefficients are adapted to minimize undesired deviations between the set of filtered samples and the second set of observed samples.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser. No. 09 / 730,681, filed on Dec. 6, 2000, which claims benefit of U.S. Provisional Application No. 60 / 190,226, filed Mar. 15, 2000. Both of those applications are incorporated herein by reference, and all U.S. patents or patent applications, published or appended articles, and any other written materials incorporated by reference therein are also specifically incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] Communication systems frequently separate signals by using a plurality of signal paths that have a predetermined vector relationship. By suitably combining the signal paths, such systems can cancel out undesired signals by mathematically exploiting predetermined phase and amplitude relationships between respective signal vectors of each signal path. [0003] Quadrature image rejection receivers employ signal paths having a quadrature relationship to discriminat...

AI Technical Summary

Benefits of technology

"The present invention provides a system and method for determining vector mismatch between signal paths. The system can determine mismatch across a range of frequencies using a periodic calibration signal with multiple tones. The system can also accommodate non-stationary errors and provide a phase-synchronous calibration signal. The system can improve accuracy and efficiency of vector mismatch determination and correction for improved performance in demodulation and image rejection."

Problems solved by technology

The precision to which such systems can correct mismatch is limited, however, because the mismatch often varies with frequency and is difficult to determine with enough precision to achieve high separation between desired and undesired signals.

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