| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for detecting and correcting phase and amplitude unbalance existing between the I(common-mode) signal component and the Q(orthogonal phase) signal component of a complex signal to be demodulated, for example, a QAM signal(orthogonal amplitude modulating signal) of a APSK signal(quadri-phase shift keying signal). SOLUTION: A circuit for detecting and correcting phase and amplitude unbalance is realized as a decision aiming control loop which is commonly used with a whole decision aiming gain control loop. Amplitude unbalance is corrected by the adjustment of one gain within the I and Q signal components and phase unbalance is by the addition of a part of one signal components within the two to one of the rest. Whole amplitude control is attained by adjusting the both gains of the signal components by a same quantity. A phase and amplitude unbalance correcting circuit 506, an amplitude unbalance detecting and calculating circuit 514, a phase unbalance detecting and calculating circuit 516 and a whole amplitude gain control circuit 518 are added to a demodulator system 500 being an execution form. |
