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1、------------------------------------------------------------------------------------------------信道频谱及线性均衡器设计基于下图所示的信道模型f=[0.0000+j*0.0000,0.0485+j*0.0194,0.0573+j*0.0253,0.0786+j*0.0282,0.0874+j*0.0447,0.9222+j*0.0301,0.1427+j*0.0349,0.0835+j*0.0157,0.0621+j*0.0078,0.0359+j*0.0049,0.0
2、214+j*0.0019]一,研究信道的幅度谱F(ej??)(单位dB),画出频谱图。二,设计k=1(2k+1=3)及k=10(2k+1=21)的迫零均衡器。三,画出以上均衡器的频谱图C(ej??)以及等效信道谱F(ej??)C(ej??)。四,采用蒙特卡洛方法,仿真研究无均衡器,采用了3个抽头均衡器和21抽头均衡器情况下系统的符号错误率,系统采用QPSK调制。一,研究信道的幅度谱F(ej??)(单位dB),画出频谱图。若要了解离散信号的频谱特征,首先要对离散信号进行傅里叶变换或者是Z变换。在Z变换中,单位圆上的结果则对应傅里叶变换的结果,即z?e。而要得到信道的
3、频谱图,首先要对序列x(n)进行Z变换,得到X(z)。(1)MATLAB仿真程序:f=[0.0000+j*0.0000,0.0485+j*0.0194,0.0573+j*0.0253,0.0786+j*0.0282,0.0874+j*0.0447,0.9222+j*0.0301,0.1427+j*0.0349,0.0835+j*0.0157,0.0——————————————————————————————————————------------------------------------------------------------------------
4、------------------------621+j*0.0078,0.0359+j*0.0049,0.0214+j*0.0019];f1=0;forn=1:11f1=f(n)*f(n)+f1;endb=sqrt(f1);f=f/b;w=-3:2*pi/255:3;T=1;x=0;form=1:11x=x+f(m)*exp(-j*m*w*T);endx=10*log10(abs(x));figure;plot(w*T,x);xlabel('omegaT');j?ylabel('10log10
5、F(e^{jomega})
6、(dB)&
7、#39;);title('信道的幅度谱');gridon运行的结果如下图:二,设计k=1(2k+1=3)及k=10(2k+1=21)的迫零均衡器。——————————————————————————————————————------------------------------------------------------------------------------------------------(1)根据算法?q?fmCn?m?0?n??1?n?K??q0??fmC0?m?1可以求出所需的抽头系数。(2)MATLAB仿真程序F3=[
8、0.9222+j*0.030310.0874+j*0.04470.0786+j*0.0282;0.1427+j*0.03490.9222+j*0.030310.0874+j*0.0447;0.0835+j*0.01570.1427+j*0.03490.9222+j*0.03031];q3=[0;1;0];c3=F3q3;c1=0;fork=1:3;c1=c3(k)*c3(k)+c1;Fc?qcop?F?1qendd=sqrt(c1);c3=c3/dF21=[0.9222+j*0.02102110.0874+j*0.04470.0786+j*0.02820.057
9、21+j*0.025210.0485+j*0.01940.0000+j*0.0000000000000000000;0.1427+j*0.021490.9222+j*0.02102110.0874+j*0.04470.0786+j*0.02820.05721+j*0.025210.0485+j*0.01940.0000+j*0.000000000000000000;0.08215+j*0.01570.1427+j*0.021490.9222+j*0.02102110.0874+j*0.04470.0786+j*0.02820.05721+j*0.025210.04
10、85+j*