% Digital Filter
% Symbol_Rate = 8.97*10^6
% T = 1/(2*Symbol_Rate)
% Roll-Factor = Alpa(0.5)
% Filter Tap = 32
%function Dig_Out=Dig_Filter(data,SubCarrier)

%Num = 32;
%Ca_Num = Num/Subcarrier;
function Coeff=Dig_Filter(Dat,delay)

Symbol_Rate=8.97*10^6;
T=1.0/Symbol_Rate;
T1=T;

Alpa = 0.3;% input ('Enter is roll off factor of Value(0.1~0.9): ');
Tap_Num = 32;%input('Enter is Tap Number (1~32) : ');

np=1;

for t=-(Tap_Num-2)*T1/4-delay : T1/2 : (Tap_Num)*T1/4-T1/2-delay,
   sin_div=(pi*t/T);
   cos_div=(1.0-4.0*(Alpa*t/T)^2);
   if(abs(sin_div)>0.1*10^-5)
      sin_term(np) = sin(pi*t/T)/sin_div;
   else
      sin_term(np) = cos(pi*t/T);
   end;
   if(abs(cos_div)>0.1*10^-5)
      cos_term(np) = cos(Alpa*pi*t/T)/cos_div;
   else
      cos_term(np) = pi*sin(Alpa*pi*t/T)/(8.0*Alpa*t/T);
   end;
   np=np+1;
end;

Coeff_Va= sin_term.*cos_term;
%Coeff_Va=[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0];
%Coeff_Va = [0 0 0 0 0 0 0 0 0 -1 1 -1 2 -1 -11 4 28 -10 -49 21 75 -37 -124 42 255 216 27 -52 -11 16 2 -3 0 2 -2 2];
%sum(Coeff_Va)
Coeff_te=conv(Dat,Coeff_Va);%/sum(Coeff_Va);
Coeff=Coeff_te;
%figure
%tp=-(Tap_Num-2+delay)*T1/4:T1/2:(Tap_Num-delay)*T1/4-T1/2;
%stem(tp)
%hold on
%plot(Coeff_Va)
%hold off