gauss_rect_filter.m

完成GMSK信号调制

function output = gauss_rect_filter(B,filter_order,sample_rate,Rb)

Tb = 1/Rb;
n = filter_order;

if mod(n,2) == 0
    t(1:n/2) = -Tb/(2*sample_rate)-Tb/sample_rate*(n/2-1):Tb/sample_rate:-Tb/(2*sample_rate);
    t(n/2+1:n) = Tb/(2*sample_rate):Tb/sample_rate:Tb/(2*sample_rate)+Tb/sample_rate*(n/2-1);
else
    t(1:(n-1)/2) = -Tb/sample_rate*((n-1)/2):Tb/sample_rate:-Tb/sample_rate;
    t((n-1)/2+1) = 0;
    t((n-1)/2+2:n) = Tb/sample_rate:Tb/sample_rate:Tb/sample_rate*((n-1)/2);
end;

alpha = (1/B) * sqrt(log(2)/2);

output = (1/Tb) * ( QFunction(sqrt(2)*pi*(t-Tb/2)/alpha) - QFunction(sqrt(2)*pi*(t+Tb/2)/alpha) );