| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology for starting a squelch operation after determining an OFDM signal without using card correlation. SOLUTION: A conjugation signal producing unit 51 of an OFDM determination circuit 50 produces a third order distortion signal IM3 from an original signal (input signal Vin) and outputs to a conjugation signal multiplier 52. The conjugation signal multiplier 52 multiplies the original signal (input signal) which is indicated as a pair of signals of a real number signal line RL1 and an imaginary signal line IL1 by a conjunction complex number of the third order distortion signal produced by the conjugation signal producing unit 51, then outputs to an integrating circuit 53 for determination. The integrating circuit 53 for determination smoothes a multiplication result of the conjugation signal multiplier 52, and the original signal is determined as the OFDM signal based on the principle, then outputs "1" to an output disable circuit 24 as a determination signal when the result of smoothing is "0". While a cut-off signal output unit 54 outputs the determination result "0" to an output cut-off circuit 24 for cutting off the output when the result of smoothing is other than "0". COPYRIGHT: (C)2009,JPO&INPIT |
