qam_slicer.m

这是一个完整的数据传输过程的matlab例程!

function y = QAM_Slicer(Y,Nbits,opt);
% y = QAM_Slicer(Y,Nbits);
%
% Slices a QAM signal with Nbits resolution of both I and Q
% components. 
%
% Input parameters:
%     Y       complex input (scalar or vector)
%     Nbits   resolution of real and imag part of Y
%     opt     opt='norm' sets re-normlaisation to unit variance
%
% Output parameters:
%     y       2*2^Nbit QAM symbol
   
Ly = length(Y);
Levels = 2^Nbits;

% rescaling
Scale = [0.7071;
   1.5811;
   3.2404;
   6.5192];
Y = Y*Scale(Nbits);

% **** decision slicer ****
i = round(real(Y)+(Levels-1)/2);
i(i<0) = 0;
i(i>(Levels-1)) = Levels-1;

q = round(imag(Y)+(Levels-1)/2);
q(q<0) = 0;
q(q>(Levels-1)) = Levels-1;

% restore QAM symbol
y = i-(Levels-1)/2 + sqrt(-1)*(q-(Levels-1)/2);

if exist('opt'),
   if opt=='renorm',
       y = y/Scale(Nbits);
   end;
end;