zoomfft 密集频率成分的频谱校正方法
假设给定信号 x=cos(2*pi*256.4*t+40*pi/180)+5*cos(2*pi*256.9*t+60*pi/180);频率,幅值,相位的程序 function =ZoomFFT6081(x,fs,N,fe,D,L,M)
k=1:M;
w=0.5+0.5*cos(pi*k/M); %Hanning窗
fl=max(fe-fs/(4*D),-fs/2.2);%细化频率上线
fh=min(fe+fs/(4*D),fs/2.2);%细化频率下线
yf=D*fl; %移频量
df=fs/D/N;
f=fl:df:fl+(N/2-1)*df;
xz=zeros(1,N/2);
wl=2*pi*fl/fs;
wh=2*pi*fh/fs;
hr(1)=(wl-wh)/pi;
hr(2:M+1)=(sin(wl*k)-sin(wh*k))./(pi*k).*w;
hi(1)=0;
hi(2:M+1)=(cos(wl*k)-cos(wh*k))./(pi*k).*w;
k=0:N-1;
w=0.5-0.5*cos(2*pi*k/N);
for i=1:L
for k=1:N
kk=(k-1)*D+M+(i-1)*N;
xrz(k)=x(kk+1)*hr(1)+sum(hr(2:M+1).*(x(kk+2:kk+M+1)+x(kk:-1:kk-M+1)));
xiz(k)=x(kk+1)*hi(1)+sum(hi(2:M+1).*(x(kk+2:kk+M+1)-x(kk:-1:kk-M+1)));
end
xzt=(xrz+j*xiz).*exp(-j*2*pi*(0:N-1)*yf/fs);
xzt=xzt.*w;
xzt=xzt-sum(xzt)/N;
xzt1=fft(xzt);
xz=xz+(abs(xzt1(1:N/2))/N*2).^2;
end
xz=(xz/L).^0.5; D=100;
M=500;
t=(0:D*N+2*M)/fs;
x=cos(2*pi*256.4*t+40*pi/180)+5*cos(2*pi*256.9*t+60*pi/180);
=ZoomFFT6081(x,fs,N,256,D,1,M);
plot(f,xz);
频谱和幅值基波可以算的。但相位怎么求的?????
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