| 摘要 |
PROBLEM TO BE SOLVED: To obtain a correct spectrum of a signal in executing a discrete Fourier transformation, even in the case such the condition is not met that a value of window width is an integral multiple of the period of the signal whose spectrum is desired to be determined. SOLUTION: A spectrum analysis system 10 is provided, which extracts a number, N, of data (N is an integer) from a data row sampled at a sampling period T. The spectrum analysis system 10 is equipped with a data input means 11 which extracts and inputs a plurality of data sets while shifting a data extraction position, in the case an interval of N'×T (wherein N-0.5≤N'<N+0.5) is equal to a number, P, of periods of the signal, and either the number N' or P is an integer, and the other is a noninteger; a Fourier transformation means 12 which executes respective Fourier transformations; an average calculating means 13 which calculates an average of fluctuations corresponding to extraction positions; and a spectrum compensation means 14 which compensates the average by using a quadratic function wherein the fractional part of the number N' or P being the noninteger is used as a variable. COPYRIGHT: (C)2006,JPO&NCIPI
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