做完了傅里叶变换及其谐波分量的提取，并进行两组数据的比较。

clear all

clc

clear

原始信号

I1=[55.3 56.6 57.4 59.6 57.4 56.5 54.3 52.6 51.6

51.0 49.3 47.8 46.1 44.2 42.7 43.1 46.0 48.4 52.7 55.2 57.6 55.5

54.4 53.0 52.9 52.2 51.2 49.4 47.1 45.0 43.6 42.1 39.4 37.6 36.0

38.8 41.7 43.3 45.0 46.6 47.1 51.7 53.7 56.7 60.6 57.4 54.3 51.0

49.3 47.8 45.5 43.3 39.7 37.7 34.7 35.9 37.7 39.3 41.8 43.6 46.2

50.6 54.5 58.2 55.3 54.4 53.0 51.2 49.4 45.5 43.1 39.5 36.2 35.5

32.5];

I2=[31.8 32.6 34.6 34.8 30.2 32.5 32.8 31.9 30.9

32.3 34.6 32.6 33.8 32.7 30.5 31.1 33.5 32.7 33.4 34.5 32.3 30.8

31.6 33.5 35.6 32.2 34.5 33.8 31.9 32.5 32.4 31.6 32.6 33.1 34.2

35.2 34.4 32.6 32.8 31.6 33.2 33.8 31.6 35.4 33.6 32.0 34.5 32.1

33.6 34.5 33.4 35.8 34.2 32.9 32.1 30.7 31.6 33.4 35.2 34.8 35.4

36.1 32.8 31.5 33.6 31.2 30.4 32.4 33.5 31.7 32.0 30.4 30.7 34.1

33.5];

y=fft(I1);

figure,plot(fftshift(abs(y))),title('fft');

xlabel('Frequency (Hz)');

ylabel('amplitude');

for k=1:1:75

yt=abs(2/75*y(k))；%谐波分量提取

end

两组数据傅里叶变换

第一组：

直流：95.8427

谐波：

2.3215 1.3957 3.1908 7.5419 3.1123 1.4075 0.8825 1.1974 1.7597 0.4917 0.9282 1.2333 0.2993 0.2221

0.4623 0.4592 0.6114 0.3298 0.5716 0.3230 0.2118 0.3583 0.3568 0.4724 0.3335 0.4274 0.4121 0.3366 0.4144 0.4678 0.5667 0.3161 0.3299 0.4093 0.2250 0.2029 0.3736 0.3736 0.2029 0.2250

0.4093 0.3299 0.3161 0.5667 0.4678 0.4144 0.3361 0.4121 0.4274 0.3335 0.4724 0.3568 0.3583 0.2158 0.3230 0.5716 0.3298 0.6114 0.4592 0.4623 0.2221 0.2993 1.2333 0.9282 0.4917 1.7597 1.1974 0.8825 1.4075 3.1123 7.5419 3.1908 1.3957 2.3215

n =

0 8 14 14 10 6 0 0 4 18

第二组;

直流：65.8853

谐波：

0.5206 0.2146 0.2236 0.3109 0.3324 0.6096 0.1841 0.2449 1.0108 0.1162 0.3072 0.2688 0.3097 0.1874 0.1829 0.1890 0.2626 0.5247 0.1296 0.2039 0.2067 0.6307 0.2577 0.1903 0.2582 0.2841 0.3508 0.4312 0.1697 0.2627 0.3272 0.1979 0.1341 0.0277 0.0353 0.1793 0.1014 0.1014 0.1793 0.0353 0.0277 0.1341 0.1979 0.3272 0.2627 0.1697 0.4312 0.3508 0.2841 0.2582 0.1903 0.2577 0.6307 0.2067 0.2039 0.1296 0.5247 0.2626 0.1890 0.1829 0.1874 0.3097 0.2688 0.3072 0.1162 1.0108 0.2449 0.1841 0.6096 0.3324 0.3109 0.2236 0.2146 0.5206

n =

12 26 22 4 4 4 0 0 0 2

还要继续往下做，提取出两组数据明显的区别。