| 摘要 |
PROBLEM TO BE SOLVED: To attain an operation of a high transmission rate for the transmission of data without causing any interference to the outside of a working frequency band by multiplying every signal by a window function before the signal is transmitted and making the Fourier transform absolute value of the window function have the zero crossing with every working carrier frequency and also have at least the secondary maximum point of the specific attenuation against the primary maximum point. SOLUTION: A function that is shown in an expression is used as a window function. In this expression, n equals to 0 to NFFT-1, the NFFT represents the number of points which are used to a Fourier inverse function and a function ci is selected as c0=0.5093, c1=-0.4941 and c2=0.0059 when I equals to 2. Then every signal is multiplied by the window function, the Fourier transform absolute value of the window function has the zero crossing with every working carrier frequency, and a window function that has at least -30 dB and preferably at least -50 dB against the primary maximum point is used.
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