fs=10000; % 采樣頻率,自己根據實際情況設置
N=length(x); % x 是待分析的數據
n=1:N;
%1-FFT
X=fft(x); % FFT
X=X(1:N/2);
Xabs=abs(X);
Xabs(1) = 0; %直流分量置0
for i= 1 : m
[Amax,index]=max(Xabs);
if(Xabs(index-1) > Xabs(index+1))
a1 = Xabs(index-1) / Xabs(index);
r1 = 1/(1+a1);
k01 = index -1;
else
a1 = Xabs(index) / Xabs(index+1);
r1 = 1/(1+a1);
k01 = index;
end
Fn = (k01+r1-1)*fs/N; %基波頻率
An = 2*pi*r1*Xabs(k01)/(N*sin(r1*pi)); %基波幅值
Pn = phase(X(k01))-pi*r1; %基波相角 單位弧度
Pn = mod(Pn(1),pi);
end