| 摘要 |
PROBLEM TO BE SOLVED: To conduct stable automatic frequency control with a wide lock range by detecting a phase change of one optional carrier in a multi-carrier so as to obtain frequency deviation thereby reducing the effect of multi-path and fading. SOLUTION: An automatic frequency section 30 detects a phase change in one optional carrier obtained by an FFT and eliminates a modulation component from the detected phase change and a modulation elimination section 32 detects fluctuation in a local oscillator. The modulation elimination section 32 discriminates at which quadrant a reception symbol is in existence. The rotated reception symbol represents a phase shift of a carrier on the Y axis, Thus, the frequency is controlled by feeding back the frequency to the local oscillator so that the phase shift in the carrier is eliminated. Then a statistic processing section 33 averages a phase shift of the carrier from which a modulation signal is eliminated and on the occurrence of multi-path in the object carrier, the adverse effect is reduced. Then a feedback variable control section 34 conducts the feedback control proportional to a magnitude of the phase shift of the carrier from which the modulation signal is eliminated. |
