| 摘要 |
At a transmitting side, during carrier leak adjustment, quadrature modulation means uses a carrier wave having a frequency different from that at a receiving side to quadrature-modulate an outgoing signal. Feedback means feeds a modulated wave resulting from the quadrature modulation back to the receiving side. At the receiving side, quadrature demodulation means quadrature-demodulates the fed back modulated wave. Phase locking means locks the phase of the signal resulting from the quadrature demodulation to match the phase to the phase at the transmitting side. Offset detection means time-averages the phase-locked signal to detect a direct-current offset. At the transmitting side, based on the value of the direct-current offset detected at the receiving side, offset adjustment means corrects a direct-current offset of the outgoing signal to be quadrature-modulated.
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