fig_2_15_ab.m

Ultra.Wideband.Signals.and.Systems.in.Communication.Engineering.eBook-kB代码

clear all
tau=5e-10;
f_1=4e9;f_3=6e9;f_4=7e9;f_5=8e9;
t_1=0;t_3=4e-9;t_4=6e-9;t_5=8e-9;
E=1;
K=sqrt(E/tau/sqrt(pi/2));
it=0;
for t=-2e-9:1e-12:10e-9;
    it=it+1;
    s_1(it)=sqrt(2)*K*exp(-(t-t_1)^2/tau^2)*cos(2*pi*f_1*(t-t_1));
    s_3(it)=sqrt(2)*K*exp(-(t-t_3)^2/tau^2)*cos(2*pi*f_3*(t-t_3));
    s_4(it)=sqrt(2)*K*exp(-(t-t_4)^2/tau^2)*cos(2*pi*f_4*(t-t_4));
    s_5(it)=sqrt(2)*K*exp(-(t-t_5)^2/tau^2)*cos(2*pi*f_5*(t-t_5));
    s(it)=s_1(it)+s_3(it)+s_4(it)+s_5(it);
end,
figure (1);t=-2e-9:1e-12:10e-9;plot(t,s,'b');
xlabel('Time, sec');ylabel('Amplitude');grid;

iif=0;
for f=0:1e8:2e10;
    iif=iif+1;
    S_1(iif)=sqrt(2)*.5*K*tau*sqrt(pi)*exp(-(pi*tau*(f-f_1))^2)*(exp(-j*2*pi*f*t_1));
    S_3(iif)=sqrt(2)*.5*K*tau*sqrt(pi)*exp(-(pi*tau*(f-f_3))^2)*(exp(-j*2*pi*f*t_3));
    S_4(iif)=sqrt(2)*.5*K*tau*sqrt(pi)*exp(-(pi*tau*(f-f_4))^2)*(exp(-j*2*pi*f*t_4));
    S_5(iif)=sqrt(2)*.5*K*tau*sqrt(pi)*exp(-(pi*tau*(f-f_5))^2)*(exp(-j*2*pi*f*t_5));
    S(iif)=S_1(iif)+S_3(iif)+S_4(iif)+S_5(iif);
end,
figure (3);f=0:1e8:2e10;plot(f,abs(S),'r')
xlabel('Frequency, Hz');ylabel('Magnitude');grid;