Modulation scheme deciding method and modulation scheme deciding apparatus

摘要

PROBLEM TO BE SOLVED: To provide a modulation system judging method capable of judging a modulation system of a digital signal of which the communication specification is unknown, a demodulation system using it, a modulation system judging device and a demodulation device using it.;SOLUTION: The modulation system judging device is constituted so as to multiply frequencies of a modulated digital signal by a multiplication part 10, to perform Fast Fourier Transformation to a signal obtained by multiplication by an FFT part 11 and to judge a modulation system by a threshold judging part 13 based on a power spectrum obtained by the Fast Fourier Transformation. In addition, the demodulation system and method are constituted so as to further perform demodulation by a demodulation part 21 according to judgment results of the threshold judging part in addition to the modulation system judging device.;COPYRIGHT: (C)2003,JPO