深入浅出通信原理251－382.doc

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1、% I路信号 subplot(321); t=0:0.001:8; a=1/sqrt(2); x=t-0.5; y1= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-1.5; y2= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-2.5; y3= - a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-3.5; y4= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-4.5; y5= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-5

2、.5; y6= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-6.5; y7= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-7.5; y8= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); y01= y1+y2+y3+y4+y5+y6+y7+y8; plot(t,y01); axis(0 8 -2 2); grid on;% Q路信号 subplot(323); t=0:0.001:8; a=1/sqrt(2); x=t-0.5; y1= a.*sinc(x).*cos(pi*x)./(1-4.*

3、x.*x); x=t-1.5; y2= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-2.5; y3= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-3.5; y4= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-4.5; y5= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-5.5; y6= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-6.5; y7= a.*sinc(x).*cos(pi*x)./(1-4.*x.

4、*x); x=t-7.5; y8= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); y02= y1+y2+y3+y4+y5+y6+y7+y8; plot(t,y02); axis(0 8 -2 2); grid on;%QPSK调制信号 subplot(325); t=0:0.001:8; s1=y01.*cos(2*pi*10*t) ; s2=y02.*sin(2*pi*10*t); plot(t,s1-s2) ; axis(0 8 -2 2);% I路信号 subplot(322); t=0:0.001:8; a=1/sqrt(2); x=t-0.5; y1= -a

5、.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-1.5; y2= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-2.5; y3= - a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-3.5; y4= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-4.5; y5= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-5.5; y6= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-6.5; y7= -a.*

6、sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-7.5; y8= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); y01= y1+y2+y3+y4+y5+y6+y7+y8; plot(t,y01); axis(0 8 -2 2); grid on;% Q路信号 subplot(324); t=0:0.001:8; a=1/sqrt(2); x=t-1; y1= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-2; y2= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-3; y3

7、= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-4; y4= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-5; y5= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-6; y6= -a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-7; y7= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); x=t-8; y8= a.*sinc(x).*cos(pi*x)./(1-4.*x.*x); y02= y1+y2+y3+y4+y5+y6+y

8、7+y8; plot(t,y02); axis(0 8 -2 2); grid on;%QPSK调制信号 subplot(326); t=0:0.001:8; s1=y01.*cos(2*pi*10*t) ; s2=y02.*sin(2*pi*10*t); plot(t,s1-s2) ; axis(0 8 -2 2); t=0:0.001:1; y1=sin(2*pi*t); y2=sin(4*pi*t); y=y1.*y2; subplot(311);plot(t,y1);grid on; subplot(312);plot(t,y2);grid on; subplot(313);plot(

9、t,y); grid on; t=0:0.001:1; y1=sin(2*pi*t); subplot(311);plot(t,y1);grid on; t=0:0.001:0.125; y2=0; subplot(312);plot(t,y2, b);grid on;hold on; subplot(313);plot(t,y2, b);grid on;hold on; t=0.126:0.001:1; y2=sin(4*pi*(t-0.125); subplot(312);plot(t,y2); t=0.126:0.001:1; y1=sin(2*pi*t); y=y1.*y2; subp

10、lot(313);plot(t,y); K=0 K=1 K=2 k=3 k=4 K=0 k=1 K=2 k=3 K=4 k=2k=3 k=4 k=5 k=6 k=7 k=8 k=9 n=0:fs/N：（N-1)*fs/N; X=dft1(x,N); stem(n,abs(X), r); axis(0 800 0 4.5); fs=800;%采样频率 T=0.02;%截取时间长度 N=T*fs; t=0:1/fs:T-1/fs; x=cos(200*pi*t); subplot(211);stem(t,x); n=0:fs/N：（N-1)*fs/N; X=dft1(x,N); subplot(2

11、12);stem(n,abs(X); fs=800;%采样频率 T=0.04;%截取时间长度 N=T*fs; t=0:1/fs:T-1/fs; x=cos(200*pi*t); subplot(211);stem(t,x); n=0:fs/N：（N-1)*fs/N; X=dft1(x,N); subplot(212);stem(n,abs(X); function fn=circonv(x1,x2,N)%circonvt函数实现输入序列x1和x2的循环卷积,fn为输出序列%N 为循环卷积长度%实现方法:fn=sum(x1(m)*x2(n-m) mod N)if (length(x1)N|length(x2)N)%判断输入信号的长度error(N的长度必须大于输入数据的长度);endx1=x1,zeros(1,N-length(x1);x2=x2,zeros(1,N-length(x2);m=0:N-1;x=zeros(N,N);for n=0:N-1 x(:,n+1)=x2(mod(n-m),N)+1).;end;fn=x1*x;%循环计算卷积