| 摘要 |
PROBLEM TO BE SOLVED: To provide an equalizer for ODFM signal capable of reducing deterioration in characteristic due to an image signal. SOLUTION: The equalizer comprises an FFT 10, a delay circuit 20, a channel estimation unit 30, and an equalization operation unit 40. A reception signal R of an OFDM signal demodulated by the FFT 10 is delayed by the delay circuit 20 and supplied to the equalizing operation unit 40, and a frequency response H of a transmission line is estimated by the channel estimation unit 30 and supplied to the equalizing operation unit 40. In the channel estimation unit 30, pilot symbols are extracted from the reception signal R and after the reception signal is inversely Fourier-transformed and delayed, a window function circuit 34 cuts complex gain amounts within a constant time; and a comparing circuit 35 outputs complex gain amounts exceeding a threshold and the frequency response is generated through Fourier transformation. Consequently, the window function circuit 34 cuts a time width a-b having its center in the center of a one-symbol period (a), and an image signal within a time width (b) having its center in the center of the symbol period can be erased. COPYRIGHT: (C)2008,JPO&INPIT
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