Orthogonal frequency division multiplexing modulation apparatus and orthogonal frequency division multiplexing modulation, and orthogonal frequency division multiplexing demodulator, and orthogonal frequency division multiplexing demodulation method

摘要

PROBLEM TO BE SOLVED: To easily obtain a discrete signal without using an orthogonal modulation part by serially arranging the M-number of time axis signals of the real part output of an M-point discrete Fourier inverse transformation means so as to generate an intermediate frequency signal consisting of N-number of carriers. SOLUTION: A conjugate signal generating and correspondence transforming circuit 103 outputs 2N-pairs of data Rh, Sh (0=h=2N-1) from N-pair of data Ak, Bk (0=k=N-1) to a 2N point discrete Fourier inverse transformer IDFT 104. The IDFT 104 executes discrete Fourier inverse transformation arithmetic and its 2N-number of real part outputs are outputted to a parallel/serial converter(P/S) 105 as a digital parallel signal rm (0=m=2N-1). The P/S 105 executes parallel/serial conversion(P/S) and after a guard interval(GI) is inserted by a GI inserting circuit 106, a digital/analog converter(D/A) 107 converts the signal to an analog signal and a low-pass filter(LPF) 108 filters only the components of a frequency equal to or lower than fs to obtain an intermediate frequency signal.