eg:%采样频率Fs=100;t=0:1/Fs:2*pi;x=sin(2*pi*50*t)+0.5*cos(2*pi*200*t)+0.5*sin(2*pi*270*t)%幅频特性图plot(linspace(0,pi,1024),abs(fft(x,1024)))%相频特性图figure;plot(linspace(0,pi,1024),angle(fft(x,1024)))
