| 摘要 |
PROBLEM TO BE SOLVED: To provide an OFDM transmission circuit that can realize both high- speed signal transmission and high frequency utilizing efficiency. SOLUTION: The OFDM transmission circuit is provided with a plurality N of inverse Fourier transform devices 12, 13 that apply discrete inverse Fourier transform to a modulation signal of each subcarrier to output a base band complex OFDM signal, N pairs of digital/analog converters 14 to 17 that convert the complex OFDM signal into an analog signal, N pairs of filters 18 to 21 that eliminate a harmonic component from the analog complex OFDM signal, N pieces of oscillators 24, 25 that output a carrier signal with an interval of an integer multiple of a sub carrier frequency interval of the modulation signal, whose frequency synchronization is established, N pieces of orthogonal modulators 22, 23 that use the complex OFDM signal outputted from the N pairs of filters 18 to 21 and the carrier signal outputted from the oscillators 24, 25 to conduct orthogonal modulation and output OFDM signals with different center frequencies, and a compositing device 36 that composites N pieces of OFDM signals subjected to orthogonal modulation and outputs the result.
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