| 摘要 |
PCT No. PCT/EP96/02209 Sec. 371 Date Nov. 17, 1997 Sec. 102(e) Date Nov. 17, 1997 PCT Filed May 23, 1996 PCT Pub. No. WO96/41458 PCT Pub. Date Dec. 19, 1996In the case of the OFDM method, a large number of modulated carriers are transmitted using frequency division multiplexing, a spectrum having a virtually rectangular shape being produced as a result of the large number of carriers. In order to separate the carriers from one another again in the receiver, a Fast-Fourier-Transformation is carried out, it then being possible to separate each carrier cleanly from the others provided the carriers are exactly orthogonal with respect to one another. The carrier orthogonality can, however, be disturbed by various causes. Furthermore, the wanted signal must be separated from the undesired adjacent channel signals by analog or digital filtering in the receiver. In order to improve carrier and channel separation, the selectivity of the FFT filtering can be increased by enlarging the number of FFT components. However, this normally leads to an undesirably sharp increase in the computation complexity. The refinement according to the invention of the time window which is used for the FFT and the oversampling before the FFT make it possible, however, to dispense with calculation of some of the coefficients.
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