| 摘要 |
It is possible to form an OFDM signal improving frequency use efficiency. An OFDM modulation apparatus includes Nyquist filters (104, 126) for Nyquist-shaping signals (S10, S20) of two systems, delay apparatuses (123, 124) for delaying a signal of one system at ½ of the symbol period T, inverse Fourier transformers (105, 127) for OFDM-processing the respective signals after the Nyquist formation, and a switching section (130) combining the signals of the two systems by selectively outputting the signals of the two systems subjected to the OFDM processing while switching the signals at a ½ interval of the symbol period. Thus, it is possible to multiplex the two OFDM signals without interfering each other. As a result, it is possible to realize an OFDM modulation device (100) reaching twice as much as frequency use efficiency as compared to the conventional OFDM signal (i.e., reaching twice as much as the information transmission with the same frequency band as the conventional one.)
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