| 摘要 |
PROBLEM TO BE SOLVED: To enable an OFDM receiving device to detect the level of receiving signals and adjust the direction of a receiving antenna easily, even if a receiving electric field is weak and the receiving device itself is kept in an initial stage where the direction of its receiving antenna is adjusted to set a C/N ratio at about -5 dB or less. SOLUTION: In the receiving device which serves as a receiving device for a transmission device transmitting OFDM signals containing guard intervals, signals obtained by delaying the received OFDM signals by an effective symbol period and non-delayed signals are subjected to a complex multiplication operation, and the signals obtained through the complex multiplication operation are subjected to an averaging process, so that the receiving power when the receiving electrical field is low is calculated using the fact that the correlation coefficient of the guard interval period becomes dependent on the C/N ratio, signals for controlling the direction of the receiving antenna are produced on the basis of the calculated receiving electric field level, and thus the direction of the receiving antenna is controlled. COPYRIGHT: (C)2006,JPO&NCIPI
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