| 摘要 |
PROBLEM TO BE SOLVED: To provide an equalizer for an OFDM demodulator which enables adequate equalization of a transmission line, when transmission line characteristics change within a single frame period, without deteriorating the transmission efficiency in one frame. SOLUTION: Regarding initial several symbols of a data signal, equalization is performs by a preamble signal, in a manner similar to the conventional. Regarding to the following signal, equalization of a transmission line is performed by the following manner. A soft decision part 5 performs soft decision, stores the result in a RAM 6 and inputs the result in an error correction part 7, in which received data S4, after error correction, are obtained. A coding part 8 performs re-encoding of the received data S4, and a mapping part 9 performs mapping. The signal is compared with a signal of the RAM 6 by a transmission line predicting part 10 by each frequency, and equalization coefficients are calculated. An estimation error eliminating part 11 eliminates error data of soft decision result, and an averaging part 12 averages several symbols. Setting is performed in an equalization coefficient setting part 4a, thereby conducting equalization.
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