QPSK調(diào)制信號(hào)的頻譜

2017-03-24 by:CAE仿真在線來(lái)源:互聯(lián)網(wǎng)

玩了這么多年通訊,從模擬調(diào)制到數(shù)字調(diào)制,各種頻譜模板都見過(guò)吧?

射頻工程師如果兼修matalab, 試問(wèn)這個(gè)通信系統(tǒng)還有你不懂的嗎?這是跨向大牛的必經(jīng)之路啊。我這里先開個(gè)頭。

>> 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]);

>> %發(fā)送數(shù)據(jù)為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]);

>> %發(fā)送數(shù)據(jù)為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]);

>> %發(fā)送數(shù)據(jù)為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]);

>> %發(fā)送數(shù)據(jù)為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]);