matlab基础之128点fft分析数据，各个数据的频谱整体分析

numb_fft=128;

numb_seg=15;

fftout(128,10)=0;

load('271.mat');

for d=0:(numb_seg-1)

signal=round(X271_DE_time((d*128+1):(d*128+128),1)*65536/3);

fftout(1:128,(d+1))=abs(fft(signal(1:128,1),128))/128;

fftout((d*64+1):(d*64+64),1)=fftout(1:64,(d+1));

end

figure,

plot(1:64*numb_seg,fftout(1:64*numb_seg));

title('Power spectral density');

xlabel('Frequency (Hz)');

set(gca,'XTickMode','manual','XTick',[64,128,192,64*4,64*5,64*6,64*7,64*8,64*9,64*10,64*11,64*12,64*13,64*14,64*15]);

set(gca,'YTickMode','manual','YTick',[500,1000,1500,2000,2500]);

grid;