zaiboshu.m

多模光纤的信道特性研究

N=20;a=ones(1,N);
for i=2:N
    a(i)=i*a(i-1);
end
for k=1:10
    j=k;x=N-j;y=exp(-pi*x^2/4);
    b(j)=a(j)*a(N-j);
    A(j)=a(N)/b(j);
    B(j)=0.0078^j;
    C(j)=0.9922^x;
     P1(j)=log10(A(j)*B(j)*C(j));  
end

N=30;a=ones(1,N);
for i=2:N
    a(i)=i*a(i-1);
end
for k=1:10
    j=k;x=N-j;y=exp(-pi*x^2/4);
    b(j)=a(j)*a(N-j);
    A(j)=a(N)/b(j);
    B(j)=0.0078^j;
    C(j)=0.9922^x;
    P2(j)=log10(A(j)*B(j)*C(j));  
end

N=40;a=ones(1,N);
for i=2:N
    a(i)=i*a(i-1);
end
for k=1:10
    j=k;x=N-j;y=exp(-pi*x^2/4);
    b(j)=a(j)*a(N-j);
    A(j)=a(N)/b(j);
    B(j)=0.0078^j;
    C(j)=0.9922^x;
     P3(j)=log10(A(j)*B(j)*C(j));  
end

N=50;a=ones(1,N);
for i=2:N
    a(i)=i*a(i-1);
end
for k=1:10
    j=k;x=N-j;y=exp(-pi*x^2/4);
    b(j)=a(j)*a(N-j);
    A(j)=a(N)/b(j);
    B(j)=0.0078^j;
    C(j)=0.9922^x;
    P4(j)=log10(A(j)*B(j)*C(j)); 
end

N=60;a=ones(1,N);
for i=2:N
    a(i)=i*a(i-1);
end
for k=1:10
    j=k;x=N-j;y=exp(-pi*x^2/4);
    b(j)=a(j)*a(N-j);
    A(j)=a(N)/b(j);
    B(j)=0.0078^j;
    C(j)=0.9922^x;
    P5(j)=log10(A(j)*B(j)*C(j)); 
end

N=70;a=ones(1,N);
for i=2:N
    a(i)=i*a(i-1);
end
for k=1:10
    j=k;x=N-j;y=exp(-pi*x^2/4);
    b(j)=a(j)*a(N-j);
    A(j)=a(N)/b(j);
    B(j)=0.0078^j;
    C(j)=0.9922^x;
    P6(j)=log10(A(j)*B(j)*C(j)); 
end
k=1:10;
figure,plot(k,P1,'-+',k,P2,':d',k,P3,'-.h',k,P4,'--x',k,P5,'-v',k,P6,'-*')
axis([1,8,-6,0])
grid on
legend('N=20','N=30','N=40','N=50','N=60','N=70')
xlabel('落在衰落点上的载波数k'),ylabel('概率 P (dB) ')