实训三 数字信号基带传输的仿真设计

1、实训三 数字信号基带传输的仿真设计1、 实验内容1、 基带信号采用不归零矩形脉冲或升余弦滚降波形，基带信号的功率谱密度分析。 2、 误码率的计算：和误码率之间的性能曲线3、眼图的生成 4、匹配滤波器2、 程序与仿真图1. %二进制不归零矩形脉冲clc;close all;clear all;N_sample=100;N_num=1000;t=0/N_sample:1/N_sample:N_num-1/N_sample;st=0;for i=1:20 d=(randint(1,N_num)*2-1); st_bb=rectpulse(d,N_sample); %将矩阵连接 window=boxc

2、ar(length(st_bb); %矩形加窗函数 pxx,f=periodogram(st_bb,window,216,N_sample); %计算功率谱密度函数，st_bb为待求函数，window是所使用的窗口，长度必须和待求函数一致 % 2*16是采样点数 N_sample，采样频率 st=st+pxx;endst=st/20;figure(1);subplot(2,1,1);plot(t,st_bb); title('基带信号波形');axis(0 15 -1.5 1.5);grid on;subplot(2,1,2);plot(-1*flipud(f);f,0.5*f

3、lipud(st);st); title('基带信号功率谱'); %dlipud实现矩阵上下翻转axis(-8 8 0 2);grid on;%二进制滚降系数为1st_rc=rcosflt(d,1,80,'fir',1,1);figure(2);subplot(2,1,1);plot(0:1/50:35-1/50,st_rc(1:35*50);axis(0 15 -2 2);grid on; title('基带信号波形(滚降系数为1)');st1=0;for i=1:5 d=(randint(1,N_num)*2-1); st_re=rcosfl

4、t(d,1,40,'fir',1,1); window=boxcar(length(st_rc); px1,f=periodogram(st_rc,window,216,N_sample); st1=st1+px1;endst1=st1/5;subplot(212);plot(-1*flipud(f);f,0.5*flipud(st);st);title('基带信号功率谱(滚降系数为1)');axis(-5 5 0 1.5);grid on;%n=106;snr_db=0:12;ber=zeros(1,length(snr_db); %生成0矩阵for i=1:

5、length(snr_db) d=(randint(1,n)*2-1); dwn=awgn(d,snr_db(i); %加性高斯白噪声 d_r=sign(dwn); %置位-1或1 ber(i)=length(find(d=d_r)/n;%endpe=0.5*erfc(sqrt(10.(snr_db/10)/2);figure(3);semilogy(snr_db,ber,'k*');hold on;grid on;semilogy(snr_db,pe,'r-');xlabel('A/&');ylabel('ber');l

6、egend('ber','ber_Theory');2.clcclear all;close all;figure;ht=rcosflt(1,1,200,'fir/sqrt',1,3);subplot(2,2,1)plot(ht);axis(0 1200 -0.03 0.10 );grid on;ht=rcosflt(1,1,200,'fir/sqrt',0.75,3);subplot(2,2,2)plot(ht);axis(0 1200 -0.03 0.10 );grid on;ht=rcosflt(1,1,200,'f

7、ir/sqrt',0.5,3);subplot(2,2,3)plot(ht);axis(0 1200 -0.03 0.10 );grid on;ht=rcosflt(1,1,200,'fir/sqrt',0.25,3);subplot(2,2,4)plot(ht);axis(0 1200 -0.03 0.10 );grid on;3.clear all;N=1000;x=sign(randn(1,N);Ts = 1;alpha = 1;y = rcosflt(x,1/Ts,100,'fir',alpha,5);figure(3);plot(y);titl

8、e('多个滚降信号时域波形');axis(0,3000,-1.5,1.5);grid on;4.clear all;N=1000;x=sign(randn(1,N);Ts = 1;alpha = 1;y = rcosflt(x,1/Ts,100,'fir',alpha,2);eyediagram(y,300,4);title('无噪声时眼图');grid on;%clear all;N=1000;x=sign(randn(1,N);Ts = 1;snr = 30;alpha = 1;y = rcosflt(x,1/Ts,100,'fir&

9、#39;,alpha,2);y1 = awgn(y,snr);eyediagram(y1,300);title('SNR=30dB时的眼图');grid on;%clear all;N=1000;x=sign(randn(1,N);Ts = 1;snr = 20;alpha = 1;y = rcosflt(x,1/Ts,100,'fir',alpha,2);y1 = awgn(y,snr);eyediagram(y1,300);title('SNR=20dB时的眼图');grid on;%clear all;N=1000;x=sign(randn

10、(1,N);Ts = 1;snr = 10;alpha = 1;y = rcosflt(x,1/Ts,100,'fir',alpha,2);y1 = awgn(y,snr);eyediagram(y1,300,4);title('SNR=10dB时的眼图');grid on;%clear all;N=1000;x=sign(randn(1,N);Ts = 1;snr = 0;alpha = 1;y = rcosflt(x,1/Ts,100,'fir',alpha,2);y1 = awgn(y,snr);eyediagram(y1,300,4);title('SNR=0dB时的眼图');grid on;5.clc clear all;N