《合成孔径雷达成像算法与实现》Figure3.4

代码对补零信号与未补零信号都进行了实现，补零信号更加贴近书中图3.4的样子：

clc
clear all
close all%参数设置
TBP = 100;                              %时间带宽积
T = 10e-6;                              %脉冲持续时间
alpha_os = [1.4,1.2,1.0,0.8];           %过采样率%补零信号与不补零信号
G = figure;
H = figure;for i=1:4%参数计算B = TBP/T;                          %信号带宽K = B/T;                            %线性调频频率F = alpha_os(i)*B;                  %采样率N = 2*ceil(F*T/2);                  %采样点数dt = T/N;                           %采样时间间隔df = F/N;                           %采样频率间隔%变量设置t = -T/2:dt:T/2-dt;                 %时间变量f = -F/2:df:F/2-df;                 %频率变量f_zero = -F/2:F/(2*N):F/2-F/(2*N);  %补零后的频率变量%信号表达st = exp(1j*pi*K*t.^2);             %chirp信号复数表达式Sf1 = fft(fftshift(st));            %chirp信号频谱表达式st_zero = [st,zeros(1,N)];          %chirp信号补零表达式Sf2 = fft(fftshift(st_zero));       %chirp信号补零频谱表达式%不补零信号绘图figure(G)subplot(4,2,2*i-1),plot(t*1e+6,real(st))axis([-5 5,-1.2 1.2])subplot(4,2,2*i),plot(f*1e-6,abs(Sf1))axis([-4 4,0 22])%补零信号绘图figure(H)subplot(4,2,2*i-1),plot(t*1e+6,real(st))axis([-5 5,-1.2 1.2])subplot(4,2,2*i),plot(f_zero*1e-6,abs(Sf2))axis([-4 4,0 22])end