| 摘要 |
The present invention provides a method and an apparatus for eliminating direct current offset. The method comprises the steps of: calculating Euclidean distances between every two demodulation symbols of a plurality of demodulation symbols based on Quadrature Phase Shift Keying (QPSK) modulation; determining four sets from the plurality of demodulation symbols in accordance with the Euclidean distances between the demodulation symbols, each set corresponding to a modulation direction for the QPSK modulation; performing Euclidean distance weighted summation on the determined four sets respectively, and selecting a demodulation symbol with the minimum weighted summation value from each set as a rough estimation point for the QPSK modulation, so as to obtain four rough estimation points; re-determining four sets from the plurality of demodulation symbols in accordance with the Euclidean distances between the demodulation symbols and the rough estimation points; performing Euclidean distance weighted summation on the re-determined four sets respectively, and selecting a demodulation symbol with the minimum weighted summation value from each set as a precise estimation point; and performing direct current offset calculation and compensation in accordance with the precise estimation points. The present invention can improve the demodulation performance of a system.
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