g_t.m

根升余弦函数

function [g] = G_t( t,a,Ts)
%UNTITLED1 Summary of this function goes here
%  Detailed explanation goes here
%  a为滚降系数
%Ts =1; %receive signal symbol 
%ycx本函数输入t是一段离散时间量，a为一个滚降系数，接收Ts采样？？ 输出RRC g为离散的根余弦
 
%******************************Rising cosine pulse************************************
% t1=pi*t/T;
% g=sin(t1)./t1.*cos(a*t1)./(1-4*a^2*t.^2/T^2);   

%******************************Root Rising cosine pulse**RRC!******************************

% for u =1:length(t)
%     if t(u)==0
%         g(u)=(1+(4/pi-1)*a)/Ts;              % ycx  与t无关！！
%     else if t(u)==1/(4*a)|| t(u)==-1/(4*a)
%             g(u)=sqrt(2)*a*((pi-2)*cos(pi/(4*a))+(pi+2)*sin(pi/(4*a)))/(2*pi);  %ycx  与t无关！！   
%         else
%             g(u) = 1/(pi*t(u)*(1-(4*a*t(u)/Ts)^2))*(4*a*t(u)/Ts*cos(pi*(1+a)*t(u)/Ts)+sin(pi*(1-a)*t(u)/Ts));
%         end;
%     end;
% end;

for i = 1:length(t)
    if t(i) == 0
        g(i) = ( 1 + (4/pi-1)*a )/Ts ;
    else if(abs(abs(t(i))-Ts/(4*a))<1e-20)          % ycx ???
            g(i) = sqrt(2)*a/(2*pi*Ts)*( (pi-2)*cos(pi/(4*a)) + (pi+2)*sin(pi/(4*a)) ) ;
         else
             g(i) = ( 4*a*t(i)/Ts*cos( pi*(1+a)*t(i)/Ts)+ sin(pi*(1-a)*t(i)/Ts) )/(pi*t(i)*(1-(4*a*t(i)/Ts)^2) ) ;
         end
     end
 end