| 摘要 |
PROBLEM TO BE SOLVED: To obtain a demodulator capable of performing accurate frame synchronization even in the presence of a large clock frequency shift. SOLUTION: The demodulator is equipped with a fast Fourier transformation means and a demodulating means, and carries out OFDM (Orthogonal Frequency Division Multiplexing) demodulation. The demodulator includes a clock frequency shift detector 5 which detects a clock frequency shift on the basis of a synchronizing signal for frame synchronization included in a reception signal, a clock frequency corrector 4 which corrects the clock frequency shift of the reception signal in the front stage of an FFT unit 6, and a TG 7 which controls a frame pulse position indicative of the head of a frame on the basis of the synchronizing signal. The FFT unit 6 performs fast Fourier transformation for the reception signal corrected by the clock frequency corrector 4 with the position of the frame pulse as the frame head position, and a data extractor 8 demodulates the signal after the fast Fourier transformation. COPYRIGHT: (C)2008,JPO&INPIT
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