| 摘要 |
PROBLEM TO BE SOLVED: To improve amplitude variation tolerance in a whole burst without impairing throughput. SOLUTION: In an OFDM (orthogonal frequency division multiplex) demodulator, an automatic gain control amplification means 1 performs gain control so that an output signal level becomes constant according to a level of an OFDM receiving signal. An OFDM signal power average means 7 averages an output signal of the automatic gain control amplification means for a long time, and obtains an AGC control value from the difference from a target. An automatic gain control amplification means control means 4 controls the automatic gain amplification means by an OFDM receiving signal, output of a burst detection means 3, an output of a packet signal detection means 6, and an output of the OFDM signal power average means; and composes an AGC circuit in which response calculating a AGC control value from a preamble for AGC in the OFDM receiving signal is fast, and an AGC circuit in which response to add an AGC control value obtained by the OFDM signal power average means to the calculated AGC control value is low. COPYRIGHT: (C)2007,JPO&INPIT
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