Читать книгу Inverse Synthetic Aperture Radar Imaging With MATLAB Algorithms - Caner Ozdemir - Страница 81

%--------------------------------------------------------- % This code can be used to generate Figure 2.18 %--------------------------------------------------------- clear close all sigma=1e-10; % set sigma t=-25e-9:0.01e-9:25e-9; % choose time vector N=length(t); mex(2451:2551)=1/sqrt(2*pi)/sigma^3*(1-t(2451:2551). ^2/sigma^2)... .*(exp(-t(2451:2551).^2/2/sigma^2)); % form wavelet mex=mex/max(mex);mex(N)=0; % Frequency domain equivalent dt=t(2)-t(1); % time resolution df=1/(N*dt); % frequency resolution f=0:df:df*(N-1); % set frequency vector mexF=fft(mex)/N; % frequency domain signal %---Figure 2.18(a)------------------------------------------------ plot(t(2251:2751)*1e9,mex(2251:2751),'k','LineWidth',2); grid minor set(gca,'FontName', 'Arial', 'FontSize',12,'FontWeight','Bold'); xlabel('\ittime, ns'); ylabel('\itamplitude, V'); axis([-2.5 2.5 -.5 1.1]); %---Figure 2.18(a)------------------------------------------------ figure plot(f(1:750)/1e9,20*log10(abs(mexF (1:750))),'k','LineWidth',2); grid minor set(gca,'FontName', 'Arial', 'FontSize',12,'FontWeight','Bold'); axis([0 f(750)/1e9 -180 -40]); xlabel('\itfrequency, GHz'); ylabel('\itfAmplitude, dB');