| 摘要 |
Influence from an adjacent signal is prevented even if a guard band is not provided. A phase comparison unit 21 compares a reference window signal input to a PLL circuit 4 and a window signal supplied from a frequency division circuit 22 and outputs the comparison result to an LPF 23 . The LPF 23 extracts a low frequency component from the input signal and outputs the same to a voltage controlled oscillator 24 . The signal output from the voltage controlled oscillator 24 is supplied as a clock to units of an OFDM modulation circuit 2 and, at the same time, supplied to the frequency division circuit 22 . The frequency division circuit 22 divides the frequency of the supplied signal to thereby generate a new window signal and supplies the same to an IFFT unit 13 . Further, the generated window signal is supplied to a PLL circuit 5 . The PLL circuit 5 generates a clock for controlling a frequency modulation circuit 3 based on the supplied window signal.
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