| 摘要 |
PROBLEM TO BE SOLVED: To provide a demodulation circuit in which the eliminating effect of a frequency offset is prevented by the increase in the frequency offset resulting in increasing an offset component in a reception symbol wave thereby causing considerable distortion to a waveform of the reception symbol wave. SOLUTION: A frame synchronization detection circuit 14 detects a frame synchronizing signal and provides a detection signal (d) to a counter circuit 15 by using a time given to one frame for the period, the counter circuit 15 counts the time by an oscillation signal P from a voltage controlled oscillator 10 to provide a count N to an error detection circuit 16. The error detection circuit 16 obtains a difference between a reference count stored in advance and a moving mean value of the count N for a plurality of number of times, provides the voltage corresponding to the difference to the voltage controlled oscillator 10 as a control voltage V so as to approach the frequency of an oscillation signal P to the frequency when no frequency offset is present. |
