版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/Destiny0321/article/details/53096327
这里,信号持续时间T = 10us,信号带宽B = 10MHz,改变过采样率(1.4, 1.2, 1.0, 0.8)的取值以探索过采样率对信号频谱的影响。
% SAR_Figure_3_4
% 2016.10.12
close all;clear all;clc
T = 10e-6; % 信号持续时间
B = 10e6; % 信号带宽
K = B/T; % 调频率
ratio = [1.4,1.2,1.0,0.8];
Num = length(ratio);
figure,set(gcf,'Color','w');
for ii = 1:Num
Fs = ratio(ii)*B; % 采样频率
dt = 1/Fs; % 采样间隔
N = ceil(T/dt); % 采样点数
t = ((0:N-1)-N/2)/N*T; % 时间轴
f = ((0:N-1)-N/2)/N*Fs;
st0 = exp(1i*pi*K*t.^2); % 生成信号
st1 = [st0,zeros(1,N)]; % 补零后的信号,补1倍
Sf = fft(st1);
n = (0:2*N-1)/2;
subplot(Num,2,2*ii-1),plot(t*1e6,real(st0));axis tight
ylabel(['\alpha_{os}=',num2str(ratio(ii))]);
if(ii == 1)
title('信号实部');
end
if(ii == Num)
xlabel('时间(\mus)');
end
subplot(Num,2,2*ii),plot(n,abs(Sf));axis tight
if(ii ==1)
title('频谱幅度');
end
if(ii == Num)
xlabel('频率(单元)');
end
end