chirpaftermatchedfilter.asv

线性调频（LFM）脉冲压缩雷达仿真,线性调频脉冲压缩的Matlab程序

%%demo of chirp signal after matched filter
T=10e-6;                                   %pulse duration10us
B=30e6;                                    %chirp frequency modulation bandwidth 30MHz
K=B/T;                                       %chirp slope
Fs=10*B;Ts=1/Fs;                     %sampling frequency and sample spacing
N=T/Ts;
t=linspace(-T/2,T/2,N);
St=exp(j*pi*K*t.^2);                     %chirp signal
Ht=exp(-j*pi*K*t.^2);                    %matched filter
Sot=conv(St,Ht);                         %chirp signal after matched filter
figure(1)
L=2*N-1;
t1=linspace(-T,T,L);
Z=abs(Sot);Z=Z/max(Z);             %normalize 
Z=20*log10(Z+1e-6);
Z1=abs(sinc(B.*t1));                   %sinc function
Z1=20*log10(Z1+1e-6);
t1=t1*B;                                         
plot(t1,Z,t1,Z1,'r.');
axis([-15,15,-50,inf]);grid on;
legend('emulational result','sinc function');
xlabel('Time in sec times\itB');
ylabel('MagnituddB');
title('\fontsize{9}脉冲压缩后的回波(归一化后)');
figure(2)                                   %zoom
N0=3*Fs/B;
t2=-N0*Ts:Ts:N0*Ts;
t2=B*t2;
plot(t2,Z(N-N0:N+N0),t2,Z1(N-N0:N+N0),'r.');
axis([-inf,inf,-50,inf]);grid on;
set(gca,'Ytick',[-13.4,-4,0],'Xtick',[-3,-2,-1,-0.5,0,0.5,1,2,3]);
legend('\fontsize{9}仿真结果','理论结果');
xlabel('\fontsize{9}时间\times\itB  (s)');
ylabel('\fontsize{9}相对幅度dB');
title('\fontsize{9}脉冲压缩后的回波(归一化后局部图)');