| 摘要 |
A method and an arrangement for determining correction parameters used for correcting DC-offset of an I/Q modulator in a transmitter, which transmitter comprises an I/Q modulator (7) for I/Q-modulating a signal to be transmitted and a corrector (4A, 4B, 16) for correcting the DC-offset (DC) caused by the I/Q modulator according to the correction parameters, which arrangement comprises means (9) for sampling the I/Q-modulated test signals to be transmitted, which are formed from I/Q-plane test vectors (T1, T2) being comprised of I- and Q-test signals fed into the transmitter, means (14) for A/D-converting the signal samples taken from the test signals to be transmitted, means (15) for I/Q-demodulating the signal samples digitally into I- and Q-feedback signals, means (17) for determining the DC-offset (DC) caused by the I/Q modulator on the basis of the test vectors and the feedback vectors (M1, M2) caused by the test vectors and formed from the I- and Q-feedback signals, and means (17) for determining the correction parameters of DC-offset on the basis of the determined DC-offset.
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