| 摘要 |
PROBLEM TO BE SOLVED: To achieve stable reception in an entire closed space by enhancing a right reception place rate without using a plurality of transmission means, in particular, a plurality of antennas when receiving orthogonal frequency division multiplexing (OFDM) digital waves such as integrated services digital broadcasting for terrestrial (ISDB-T) digital broadcast waves within the closed space such as an underground shopping area or underground parking lot surrounded with radio reflectors. SOLUTION: A closed-space transmission apparatus of the present invention comprises: a leakage coaxial cable 302; a means for inputting an input signal to one terminal of the leakage coaxial cable 302; a means for temporally changing at least one of the amplitude, frequency, phase and delay time of a signal outputted from the other terminal of the leakage coaxial cable 302; and a means for inputting a signal obtained by the temporal change means to the other terminal of the leakage coaxial cable 302, and is configured to temporally change radiation characteristics or a radiation pattern of radio waves to be radiated from the leakage coaxial cable 302 into the closed space surrounded with radio reflectors. COPYRIGHT: (C)2009,JPO&INPIT
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