Matlab与通信系统仿真 LAB6.docxVIP

LAB5:BasebandSignalTransmissionII

Ⅰ.

Task1:

Ⅰ.Task1

Consider4ASKmodulation.Thesignalsare:

and

,

whered=1,T=1,fc=5Hz,themappingrulefromthebitpairtomis:00-1,01-2,11-3,10-4.

(1)Ifthemessagebitsare1100100001,plotthecorresponding4ASKsignalinbothtimeandfrequencydomain,samplingfrequencyfs=1000Hz.

(2)Givetheaveragesignalenergyperbit,i.e.,Eb,for4ASK.

(3)DenoteSNRasEb/N0,plotthetheoreticalSER(symbolerrorrate)andsimulatedSER,forSNR=0:2:8dB.

Hint:refertotheslidesandcodesrelatedto4PAMbasebandsignalinCh5ppt.

Code:

LAB6_1.m

%MATLABscriptforIllustratedProblem6.1

%initaltheparameters

T=1;%Symbolexzistingtime

delta_T=T/1000;%samplinginterval

fc=5/T;%carrierfrequency

M=4;

d=1;

%1100100001

Sym=[3,1,4,1,2];

A_m=(2*Sym-1-M)*d;%amplitude

t=[0:delta_T:length(Sym)-delta_T];%timeaxis

N=length(t);

g_T=sqrt(2/T)*ones(1,N);

fori=1:N

forj=1:length(Sym)

if(t(i)j)

u_m(i)=A_m(j)*g_T(i)*cos(2*pi*fc*t(i));

break;

end

end

end;

[sf,U_m]=T2F(t,u_m);

%Plottingcommandsfollow.

figure(1);

plot(t,u_m);

figure(2);

plot(sf,abs(U_m));

SNRindB1=0:2:8;%SNRforbit

SNRindB2=0:0.1:8;

fori=1:length(SNRindB1),

%simulatederrorrate

smld_err_prb(i)=ASK4_symerr(SNRindB1(i));%simulatedbitandsymbolerrorrates

end;

fori=1:length(SNRindB2),

%signal-to-noiseratio

SNR_per_bit=exp(SNRindB2(i)*log(10)/10);

%theoreticalerrorrate

theo_err_prb(i)=(3/2)*Qfunct(sqrt((4/5)*SNR_per_bit));%theoreticalSymbol-errorrate

end;

%Plottingcommandsfollow.

figure(3)

semilogy(SNRindB1,smld_err_prb,*);

hold

semilogy(SNRindB2,theo_err_prb);

ASK4_symerr.m

function[p]=ASK4_symerr(snr_in_dB)

%[0p0]=ASK4_symerr(snr_in_dB)

%0simulatestheprobabilityoferrorforthe