| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency spectral analyzer which performs accurate spectral analyses over a full frequency range to be analyzed and outputs their results. SOLUTION: An analog input signal f(t) is read (S1), which is subjected to A/D conversion to obtain N sample numbers of digital data f(n) (S2). The obtained N numbers of digital data f(n) is multiplied by a window function W(n) to obtain data W(n)×f(n) (S3). DFT is performed on the data W(n)×f(n) by FFT to obtain complex data F(k) (S4). A power spectrum 2¾F(k)¾<SP>2</SP>as a synthesized value of positive and negative frequency components is calculated (S5). A peak frequency k<SB>i</SB>is searched for, while a peak power P(k<SB>i</SB>) is calculated to be replaced with a value 2¾F(k)¾<SP>2</SP>at the peak frequency which has been searched for (S6). A power spectrum evaluated with a dB value is calculated, and the result is displayed as an image (S7). COPYRIGHT: (C)2005,JPO&NCIPI
|
