64QAM, 256QAM MODULATION ANALYSIS METHOD

PROBLEM TO BE SOLVED: To attain analysis of 64 point QAM modulation. SOLUTION: A maximum amplitude and a minimum amplitude of base band I, Q input signals are retrieved (S5), a gain is decided so that the minimum amplitude is in matching with a minimum amplitude of 1st to 9th amplitudes taken in a 64 point QAM signal space (S6), the gain is multiplied with each symbol point string (S7), the symbol point string is phase-rotated by πi/256 rad each to produce an ideal symbol point string (S10). The correlation between this string and the original input symbol point string is obtained till an angle πi/256 reaches π/4, and the gain is decided so that the minimum amplitude is in matching with a 2nd standard amplitude (S15). Whether or not the product of the gain and the maximum amplitude is larger than a sum of a prescribed value to the standard maximum amplitude is discriminated (S17), and when larger, the phase rotation at that time is given to an input symbol to obtain a frequency error.