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clear;
N=1024; %采样点数
fs=1; %采样频率(此时经调频傅立叶变换后的成像可观察到峰值,当采样频率扩大时,例如变为100时,最终得到的图像没有明显的峰值)
c=3e8;
f0=11.1e6; %LFM信号中心频率
w0=5.2e5; %LFM信号调频率
for n=1:N
s(n)=5*exp(complex(0,4*pi/c*(f0*(n/fs)+w0*(n/fs)^2))); %LFM信号表达式
end
f=f0-512*f0/1024:f0/502:f0+512*f0/1024; %中心频率搜索范围
p=w0-512*w0/1024:w0/502:w0+512*w0/1024; %调频率搜索范围
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%调频傅立叶变换%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
mf_fft=zeros(length(f),length(p));
for i=1:length(f)
temp=zeros(length(p),1);
for k=1:N;
temp=temp+s(k)*exp(complex(0,-4*pi/c*(f(i)*(k/fs)+p'*(k/fs).^2)));
end
mf_fft(:,i)=temp;
end
%smf_fft=MF_fft(s,f1,w1);
figure,
mesh(abs(mf_fft));