| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency characteristic calculating circuit, capable of observing delay waves of delay time which is not less than 1/3 of an effective symbol period, even for an OFDM signal using a multi-level QAM. SOLUTION: In OFDM system digital broadcasting or digital transmission, a frequency characteristic calculating circuit for calculating the frequency characteristics of a received OFDM signal is provided with a means for determining the amplitude value and phase value of each carrier from all input complex frequency data to be inputted to the circuit, and for outputting the complex determined value of each carrier and a means for inputting the complex judged value of each carrier and the input complex frequency data prior to the determination, and for dividing the input complex frequency data prior to the determination by the complex judged value for all the carriers, and for outputting the quotient as the frequency characteristics of the OFDM signal.
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