| 摘要 |
PROBLEM TO BE SOLVED: To identify the actual value of a communication wave, which is classified by multiple-value frequency shift modulation, as FSK. SOLUTION: A multiple-value frequency shift modulation identifying method comprises a histogram generation process (step S30) for generating a histogram with respect to a symbol clock which is extracted from a reception signal by an unknown digital modulation system; superimposition processes (steps S31, S32) for making the value of the horizontal axis of the histogram in the symbol clock, which is outputted in the histogram generation process, into an absolute value; phase shift processes (steps S33, S34) for performing the phase shift of the symbol clock of the histogram where the horizontal axis value is made into the absolute value in the superimposition processes; and determination processes (steps S35, S36) for comparing the phase value of the symbol clock whose phase is shifted in the phase shift processes with a threshold and determining the multiple values of the frequency shift modulation. COPYRIGHT: (C)2006,JPO&NCIPI
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