Patent ID: 7359314

Claim:
A demodulation method for demodulating a transmission signal having a plurality of symbols which are repetition signals, each of which has a guard interval and a data interval and each symbol having a same term, comprising the steps of: receiving said transmission signal; fetching said data interval of said symbols from said received transmission signal in accordance with a Fourier Fast Transformation (FFT) window; delaying said received transmission signal by said data interval; calculating a difference between said received transmission signal and said delayed transmission signal; detecting a reference position of said FFT window in each of said received symbols of said received transmission signal based upon the result of the calculation of said difference; controlling the position of said FFT window for fetching said data interval of said received transmission signal in order to demodulate said data interval based upon said detected reference position of said FFT window; and demodulating said received transmission signal being obtained in the step of fetching said data interval.