clear;
clc;
close all;
fr=1.6e3;%脈沖重復頻率
tr=1/fr;%脈沖重復周期
fs=1e6;%采樣頻率
ts=1/fs;%采樣周期

f_doppler=1000;%多普勒頻率

t=0:1/fs:tr-1/fs;%一個脈沖重復時間軸

x=ones(1,2);%回波中目標的回波

n=length(x);
N=fs/fr;
x_1=[zeros(1,120),x,zeros(1,N-120-n)];%一個脈沖回波
x_8=repmat(x_1,1,8);%8個脈沖回波,一個相關處理間隔為8*tr
t_8=(0:length(x_8)-1)*ts;
s_doppler=exp(j*2*pi*f_doppler*t_8);%多普勒調制信號
 %s_doppler=cos(2*pi*f_doppler*t_8);%多普勒調制信號
randn('state', sum(100*clock));%Initialize randn to a different state each time
s_noise_i=0.1*randn(1,length(s_doppler));
randn('state', sum(100*clock));%Initialize randn to a different state each time
s_noise_q=0.1*randn(1,length(s_doppler));
y=x_8.*s_doppler+s_noise_i+s_noise_q*j;%附帶多普勒的動目標回波
 %y=x_8;
 figure('Name','附帶多普勒的動目標回波顯示')
 subplot(211)
 plot(t_8,real(y));
 subplot(212)
 plot(t_8,imag(y));
 
%%%%%%%%%%%%%%%%%%%%  產生8個FIR濾波器的濾波器組  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
a0=[ 7.135916968387e-010,1.568395747901e-008,5.471539757694e-008,9.376656588003e-008,...
  9.376656588003e-008,5.471539757694e-008,1.568395747901e-008,7.135916968387e-010]*1e10;
n=1:8;
f=linspace(0.61,1.388,8)*pi;
fn=f'*n;
fnexp=exp(j*fn);
a08=repmat(a0,1,8);
a08=reshape(a08,8,8)';
b=a08.*fnexp;
%%%%%%%% FIR濾波器的濾波器組的頻率響應曲線  %%%%%%%%%%%%
figure('Name','FIR濾波器的濾波器組的頻率響應曲線');
for n=1:8
    freqz(b(n,:),1,1024,'whole',fr)
    hold on;
end
axis([0 fr -50 100]);
%%%%%%%% FIR濾波器的濾波器組的頻率響應曲線  %%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%  產生8個FIR濾波器的濾波器組  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

yt=reshape(y,length(y)/8,8)';

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  采用FIR進行MTD處理  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
M=8;
L=length(yt);
for i=1:L
    s_temp=yt(:,i); 
    s_mtd(:,i)=b*s_temp;    
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  采用FIR進行MTD處理 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%%%%%%%  MTD處理結果顯示  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%  MTD各通道結果顯示  %%%%%
t=0:ts:(length(s_mtd)-1)*ts;
figure('Name','MTD各通道結果顯示')
subplot(241),plot(t,abs(s_mtd(1,:))),title('（第1通道）');
subplot(242),plot(t,abs(s_mtd(2,:))),title('（第2通道）');
subplot(243),plot(t,abs(s_mtd(3,:))),title('（第3通道）');
subplot(244),plot(t,abs(s_mtd(4,:))),title('（第4通道）');
subplot(245),plot(t,abs(s_mtd(5,:))),title('（第5通道）');
subplot(246),plot(t,abs(s_mtd(6,:))),title('（第6通道）');
subplot(247),plot(t,abs(s_mtd(7,:))),title('（第7通道）');
subplot(248),plot(t,abs(s_mtd(8,:))),title('（第8通道）');
%%%%%  MTD各通道結果顯示  %%%%%

%%%%%  MTD距離維結果顯示  %%%%%
figure('Name','MTD距離維結果顯示');
plot(max(abs(s_mtd)))
%%%%%  MTD距離維結果顯示  %%%%%

%%%%%  MTD速度維結果顯示  %%%%%
figure('Name','MTD速度維結果顯示')
plot(1:8,(max(abs(s_mtd'))))
%%%%%  MTD速度維結果顯示  %%%%%

%%%%%%%%%%%%%%%%%%%%  MTD處理結果顯示  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%