线性调频和巴克码组合信号的干扰抗干扰程序.rar_信号干扰_信号组合_巴克码_抗干扰_组合巴克码

close all;clear all;clc; dbstop if error; code=[1,1,1,1,1,0,0,1,1,0,1,0,1];%7位巴克码 tao=13e-6;%脉冲宽度10us fc=3e9;%调频信号起始频率 fs=1e6;%采样频率l00MHz B=5e6;%调频信号带宽 t_tao=0:1/fs:tao-1/fs; N=length(t_tao); k=pi*B/tao; n=length(code); pha=0; Tao=n*tao; u=zeros(1,n*N); t=0:1/fs:n*tao-1/fs; for i=1:n if code(i)==1 pha=pi; else pha=0; end u(1,(i-1)*N+1:i*N)=exp(j*(2*pi*fc*t_tao+k*t_tao.^2+pha)); end v = u; delay = linspace(0, Tao, n*N); freq_del = 1 / tao /200; j = 0; vfft = fft(v,n*N); for freq = -0.5/(tao):freq_del:0.5/tao; j = j+1; exf = exp(sqrt(-1)*2*pi*freq.*delay); u_times_exf = u .* exf; ufft = fft(u_times_exf,n*N); prod = ufft .* conj(vfft); ambig(:,j) = fftshift(abs(ifft(prod))'); ambig(:,j)= ambig(:,j).^2; end freq = linspace(-0.5/tao,0.5/tao,201); %freq = -0.5/(tao):freq_del:0.5/tao; delay = linspace(-0.5*Tao,0.5*Tao,n*N); figure (1) mesh(freq,delay,ambig ./ max(max(ambig))) xlabel('频率') ylabel('延时') zlabel('模糊函数') a=-0.05*Tao; b=1/(tao) ylim([-0.1*Tao 0.1*Tao]) figure (2) ambig_d=ambig(:,101); maxambig_d=max(ambig_d); plot(delay,20*log10(ambig_d/maxambig_d)) ; xlabel('延时') ylabel('零多普勒') grid axis tight figure (3) ambig_t=ambig(85,:); maxambig_t=max(ambig_t); plot(freq,20*log10(ambig_t/maxambig_t)) ; xlabel('频率') ylabel('零延时') grid axis tight figure (4) contour(freq,delay,ambig ./ max(max(ambig))) ; xlabel('频率') ylabel('延时') grid on