频谱可用CPSD函数做:cpsd(y,y,window,noverlap,nfft,fs)这里window是加窗函数,一般默认就可以了,noverlap是覆盖数据个数,一般noverlap=0.5*nfft,fs是采样频率比如:t=0:0.01:100;采样频率是1/0.01=100Hzy=(1+0.2*sin(90*2*pi*t)+0.2*sin(150*2*pi*t)).*cos(108.1*10^6*2*pi*t) 那么cpsd(y,y,[],512,1024,100)