| 摘要 |
PROBLEM TO BE SOLVED: To securely demodulate OFDM data transmitted in plural transmission modes by executing a correlation operation using correlation between a guard and data on the latter half of a valid symbol and detecting a symbol break. SOLUTION: In a correlation computing element 12, a correlation coefficient is calculated by using data obtained by delaying complex reception data on a time area, which is inputted from an A/D converter 6, by a valid symbol period. When the correlation coefficient has correlation in a guard period, a rectangular or trapezoidal waveform appears in a real symbol period in a correlation sum outputted from a correlation sum computing element 13. The mode of a transmission string, the guard period and the valid symbol period are discriminated based on the addition results of 12 ways, which are obtained by adding elements obtained by dividing the correlation sum in a real symbol period, and a symbol break is detected. When the plural elements obtained by dividing the correlation sum in the real symbol period are added, the influence of noise can be reduced and the symbol break can precisely be detected.
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