QPSK调制信号的频谱

2017-03-24 by:CAE仿真在线来源:互联网

玩了这么多年通讯,从模拟调制到数字调制,各种频谱模板都见过吧?

射频工程师如果兼修matalab, 试问这个通信系统还有你不懂的吗?这是跨向大牛的必经之路啊。我这里先开个头。

>> a=1/sqrt(2);
>> f=-9:0.001:-1;
>> x=0.5*a*sinc(f+5);
>> y=0.5*a*sinc(f+5);
>> fill3(x,f,y,'g');
>> hold on
>> f=1:0.001:9;
>> x=0.5*a *sinc(f-5);
>> y=-0.5*a*sinc(f-5);
>> fill3(x,f,y,'g');
>> grid on
>> ylabel('f');
>> zlabel('y');
>> xlabel('x');
>> axis([-0.6 0.6 -10 10 -0.6 0.6]);
>> set(gca,'YDir','reverse');
>> line([0 0],[-10 10],[0 0]);

>> %发送数据为10
>> subplot(2,2,1);
>> a=1/sqrt(2);
>> f=-9:0.001:-1;
>> x=0.5*a*sinc(f+5);
>> y=0.5*a*sinc(f+5);
>> fill3(x,f,y,'g');
>> hold on
>> f=1:0.001:9;
>> x=0.5*a *sinc(f-5);
>> y=-0.5*a *sinc(f-5);
>> fill3(x,f,y,'g');
>> grid on
>> ylabel('f');
>> zlabel('y');
>> xlabel('x');
>> axis([-0.6 0.6 -10 10 -0.6 0.6]);
>> set(gca,'YDir','reverse');
>> line([0 0],[-10 10],[0 0]);

>> %发送数据为11
>> subplot(2,2,2);
>> a=1/sqrt(2);
>> f=-9:0.001:-1;
>> x=-0.5*a*sinc(f+5);
>> y=0.5*a *sinc(f+5);
>> fill3(x,f,y,'g');
>> hold on
>> f=1:0.001:9;
>> x=-0.5*a *sinc(f-5);
>> y=-0.5*a *sinc(f-5);
>> fill3(x,f,y,'g');
>> grid on
>> ylabel('f');
>> zlabel('y');
>> xlabel('x');
>> axis([-0.6 0.6 -10 10 -0.6 0.6]);
>> set(gca,'YDir','reverse');
>> line([0 0],[-10 10],[0 0]);

>> %发送数据为01
>> subplot(2,2,3);
>> a=1/sqrt(2);
>> f=-9:0.001:-1;
>> x=-0.5*a*sinc(f+5);
>> y=-0.5*a *sinc(f+5);
>> fill3(x,f,y,'g');
>> hold on
>> f=1:0.001:9;
>> x=-0.5*a *sinc(f-5);
>> y=+0.5*a *sinc(f-5);
>> fill3(x,f,y,'g');
>> grid on
>> ylabel('f');
>> zlabel('y');
>> xlabel('x');
>> axis([-0.6 0.6 -10 10 -0.6 0.6]);
>> set(gca,'YDir','reverse');
>> line([0 0],[-10 10],[0 0]);

>> %发送数据为00
>> subplot(2,2,4);
>> a=1/sqrt(2);
>> f=-9:0.001:-1;
>> x=0.5*a*sinc(f+5);
>> y=-0.5*a *sinc(f+5);
>> fill3(x,f,y,'g');
>> hold on
>> f=1:0.001:9;
>> x=0.5*a *sinc(f-5);
>> y=0.5*a *sinc(f-5);
>> fill3(x,f,y,'g');
>> grid on
>> ylabel('f');
>> zlabel('y');
>> xlabel('x');
>> axis([-0.6 0.6 -10 10 -0.6 0.6]);
>> set(gca,'YDir','reverse');
>> line([0 0],[-10 10],[0 0]);