| 摘要 |
PROBLEM TO BE SOLVED: To suppress noise in an orthogonal frequency division multiplex(OFDM) modulation signal. SOLUTION: An intermediate frequency signal SIF is demodulated and a noise component in a null part (non-signal part) is detected as a noise component included in a signal with a subcarrier frequency. A frequency f0 of a reference frequency signal LO is feedback-controlled in response to an error rate detected by an error correction section 23. Thus, a subcvarrier in the intermediate frequency signal SIF frequency-converted by a mixer 16 on the basis of the reference frequency signal that is feedback-controlled is parted from the noise component on a frequency axis. A digital mixer/FFT arithmetic section 21 applies Fourier transform to the intermediate frequency signal SIF to suppress the noise component.
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