trfilter.m

matlab 代码,实现了ITU-T V.32建议的 modem 整体仿真实现。

function y=trfilter(alpha) %发送滤波器
T=1;
N=31;
n=-(N-1)/2:(N-1)/2;
for i=1:length(n),
    g_t(i)=0;
    for m=-(N-1)/2:(N-1)/2,
        g_t(i)=g_t(i)+sqrt(xrc(4*m/(N*T),alpha,T))*exp(j*2*pi*m*n(i)/N);
    end;
end;
g_t=real(g_t);
n2=0:N-1;
[G_T,w]=freqz(g_t,1);
subplot(2,2,1);plot(w,abs(G_T));grid on
magg_tdb=20*log(abs(G_T)/max(abs(G_T)));
subplot(2,2,2);plot(w,magg_tdb);grid on
y=g_t;
a=y(16);
y=y/a;
t=1:length(y);
subplot(2,2,3);stem(t,y);grid on