gmsk_demod.m

MSK的调制解调程序

function [gmsk_vystup] = GMSK_demod(gmsk_signal,gmsk_signal_sum,fb,w,N)
     
M = 100;
krok = 1/(fb*M);

% rozdelenie na I a Q zlozky

t = krok*(-M:M*N-1);
In_phase = gmsk_signal_sum.*cos(w*t);
Quadrature = gmsk_signal_sum.*sin(w*t);

% filtracia I(t) a Q(t) zloziek

[n,Wn] = buttord(0.1, 0.2, 1, 10); 
[b,a] = butter(n,Wn);             

In = filter(b,a,In_phase); 
Qu = filter(b,a,Quadrature);

% scitanie I(t) a Q(t) a detekcia

y = In + Qu;

tmp2(1:N) = (M:M:M*N);
for i=1:N
    if  (y(tmp2(i)) > 0)
        vystupy(i) = 1;
    else
        vystupy(i) = 0;
    end
end
gmsk_vystup = vystupy;