| 摘要 |
PROBLEM TO BE SOLVED: To change an extraction time position of a valid symbol while preventing phase rotation of each carrier obtained through discrete Fourier transformation. SOLUTION: An A/D converter circuit 13 samples a base band orthogonal frequency division multiplex(OFDM) signal in a discrete way according to a clock signal from a clock oscillation circuit 12, a symbol extract circuit 14 extracts signal data for the valid symbol period from sampled data according to a symbol window signal from a window signal generating circuit 20, and a discrete Fourier transformation(DFT) circuit 16 applies discrete Fourier transformation to signal data from the symbol extract circuit 14 to obtain demodulated data. In this case, a symbol window control circuit 17 controls a window generating time of a symbol window signal based on an output of the A/D converter 13. On the other hand, a counter circuit 21 counts a sample time according to the clock signal independently of a generating time of the symbol window signal and the DFT circuit 16 conducts transformation processing by using the sample time for a sample time of signal data for the valid symbol period. |
