信号处理の基础代码

一、计算并画频谱

Fs = 100;                     % Sampling frequency 
T = 1/Fs;                     % Sample time 
N = size(recorddata,2);       % Length of signal 
t = (0:N-1)/Fs;               % Time vector  

xx1=abs(fft(eeg)); 
xx2=fftshift(abs(fft(eeg)));

% figure 
% subplot(4,1,1) 
% plot(eeg); 
% title('eeg'); 
% subplot(4,1,2) 
% plot(xx1); 
% title('abs(fft(eeg))'); 
% subplot(4,1,3) 
% plot(xx2); 
% title('fftshift(abs(fft(eeg)))'); 
% subplot(4,1,4) 
plot((1:N/2-1)*Fs/N,xx1(1:N/2-1)*2/N);
title('plot((1:N/2-1)*Fs/N,xx1(1:N/2-1)*2/N)结果图');

 最后的横纵坐标均为真实的频率值、真实频谱幅值

参考来源：https://blog.csdn.net/Lebronze/article/details/55518218?locationNum=14&fps=1