fsk4.m

调制识别：基于决策论的通信信号调制识别实现

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function[s] =fsk4(d,fb,f1,f2,f3,f4,fs,Ac)
%clear;d=randint(1,10,4);fb=500;f1=500;f2=1000;f3=1500;f4=2000;Ac=1;fs=12000;
N=length(d);M=fs/fb;tb=1/fb;t1=1/f1;t2=1/f2;t3=1/f3;t4=1/f4;
N1=M*t1/tb; N2=M*t2/tb;N3=M*t3/tb; N4=M*t4/tb;
for j = 1:N
	if d(j)==0
	   for i = 1:M
		s((j-1)*M+i)=Ac*cos(2*pi*(i-1)/N1);
       end
    elseif d(j)==1
	   for i = 1:M
		s((j-1)*M+i)=Ac*cos(2*pi*(i-1)/N2);
       end
    elseif d(j)==2 
	   for i = 1:M
		s((j-1)*M+i)=Ac*cos(2*pi*(i-1)/N3);
       end
	else
	   for i = 1:M
		s((j-1)*M+i)=Ac*cos(2*pi*(i-1)/N4);
	   end
	end
end