pam2.m

仿真了QPSK

clear;
Fd=10;
Fs=3*Fd;
M=4;
SNR_db=0:12;
SNR1_db=0:12;

pm=zeros(13,1);
pm_theory=zeros(13,1);
for n=1:length(SNR_db)
    Eb_N0=10^(SNR_db(n)/10);
    sgma=sqrt(5/(36*Eb_N0));
    x=randint(10000,1,M);
    y=dmodce(x,Fd,Fs,'ask',M);
    ynoise=y+sqrt(Fs/Fd)*sgma*randn(length(y),1);
    z=ddemodce(ynoise,Fd,Fs,'ask',M);
    [numbers,pm(n)]=symerr(x,z);
end;
for m=1:length(SNR_db)
    Eb_N0=10^(SNR1_db(m)/10);
    temp=Qfunct(sqrt(Eb_N0*(6*(log2(M)))/(M^2-1)));
    pm_theory(m)=(2*(M-1)*temp)/M;
end
semilogy(SNR_db,pm,'*',SNR1_db,pm_theory);
xlabel('???(dB)');
ylabel('????');
legend('?????????','????????');