OFDM MODULATING AND DEMODULATING DEVICES, AND OFDM MODULATING AND DEMODULATION METHODS

摘要

PPROBLEM TO BE SOLVED: To form OFDM signals which improve frequency utilization efficiency. PSOLUTION: An OFDM device includes two respective signal systems S10 and S20; Nyquist filters 104 and 126 for carrying out Nyquist forming; delay devices 123 and 124 with which the signal of one system is delayed only one half of symbol cycle T; reverse Fourier transform units 105 and 127 for carrying out OFDM processing of each signal after Nyquist forming; and a switching unit 130 which synthesizes the signals of the two systems processed by OFDM processing, while being switched at one half of the interval of symbol cycle T so as to output them selectively. Consequently, it is made possible to carry out multiplex without making two OFDM signals interfere mutually. Furthermore, the frequency utilization efficiency can be attained twice as the conventional OFDM signal. In other words, an OFDM modulating equipment 100 with the same frequency band as the conventional one can be realized so as to transmit twice as much information as the conventional one. PCOPYRIGHT: (C)2006,JPO&NCIPI