%chnnel
slt=x_tl;
%chnnel fadeing
[h w]=size(slt);
c_real=randn(h,3)*0.5;%乘的系数就是方差；chnnel1 chnnel2 chnnel3
c_img=randn(h,3)*0.5;
c_abs=sqrt(c_real.^2+c_img.^2);
c_ang=atan(c_img./c_real);
%chnnel1
c1_abs=c_abs(:,1);
c1_abs=hor_copy(c1_abs,Fs/Rc);
c1_ang=c_ang(:,1)+1/W;
c1_ang=hor_copy(c1_ang,Fs/Rc);
t1=1/Fs:1/Fs:1/Rc;
t1=ver_copy(t1,h);
fm_ch1=slt.*c1_abs.*cos(2*pi*Fc*t1-c1_ang);%chnnel1 signal output
fm_ch1_l=reshape(fm_ch1',1,h*Fs/Rc);
[F_c1,f_c1]=gen_spectrum(fm_ch1_l,Fs);
%chnnel2
c2_abs=c_abs(:,2);
c2_abs=hor_copy(c2_abs,Fs/Rc);
c2_ang=c_ang(:,2)+2/W;
c2_ang=hor_copy(c2_ang,Fs/Rc);
t2=1/Fs:1/Fs:1/Rc;
t2=ver_copy(t2,h);
fm_ch2=slt.*c2_abs.*cos(2*pi*Fc*t2-c2_ang);
fm_ch2_l=reshape(fm_ch2',1,h*Fs/Rc);
[F_c2,f_c2]=gen_spectrum(fm_ch2_l,Fs);
%chnnel3
c3_abs=c_abs(:,3);
c3_abs=hor_copy(c3_abs,Fs/Rc);
c3_ang=c_ang(:,3)+3/W;
c3_ang=hor_copy(c3_ang,Fs/Rc);
t3=1/Fs:1/Fs:1/Rc;
t3=ver_copy(t3,h);
fm_ch3=slt.*c3_abs.*cos(2*pi*Fc*t3-c3_ang);
fm_ch3_l=reshape(fm_ch3',1,h*Fs/Rc);
[F_c3,f_c3]=gen_spectrum(fm_ch3_l,Fs);
%sum
fm_ch=fm_ch1+fm_ch2+fm_ch3;%每行表示每个chip
fm_ch_plot=reshape(fm_ch',1,h*Fs/Rc);
[F_c,f_c]=gen_spectrum(fm_ch_plot,Fs);
%%%%%%%%%%%%%%%%%%%%%%%添加噪声
Es=sum(fm_ch_plot.^2);
%SNR=0;
En=(Es/(SpB*N))/(10^((SNR-10*log10(0.5*Fs/Rb))/10));
Noise_mesh=randn(size(fm_ch)).*sqrt(En);
%Noise_mesh=zeros(size(fm_ch));
fm_ch_noised=fm_ch+Noise_mesh;
fm_ch_noised_plot=reshape(fm_ch_noised',1,h*Fs/Rc);
[F_c_noised,f_c_noised]=gen_spectrum(fm_ch_noised_plot,Fs);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5
%figure(2);
%subplot(2,2,1);
%edge=0:0.1:5;
%hist(reshape(c_abs,1,h*3),edge);
%title('信道衰减的直方图');
%subplot(2,2,2);
%plot(t(1:2*SpB),fm_ch1_l(1:2*SpB));
%title('通过信道1后的信号波形');
%xlabel('t');
%subplot(2,2,3);
%plot(t(1:2*SpB),fm_ch_plot(1:2*SpB));
%title('三条信道叠加后的信号波形');
%subplot(2,2,4);
%plot(f_c,F_c);
%title('三条信道叠加后的频谱');
%xlabel('Hz');
figure(3)
subplot(1,2,1);
plot(t(1:2*SpB),fm_ch_noised_plot(1:2*SpB));
title('带有噪声的叠加信号');
xlabel('t');
subplot(1,2,2);
plot(f_c_noised,F_c_noised);
title('加噪后的频谱');
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