% Program 3-9
% qpskmod.m
%
% Function to perform QPSK modulation
%
% Programmed by H.Harada
%

function [iout,qout]=qpskmod(paradata,para,nd,ml)

%****************** variables *************************
% paradata : input data (para-by-nd matrix)
% iout :output Ich data
% qout :output Qch data
% para   : Number of paralell channels
% nd : Number of data
% ml : Number of modulation levels
% (QPSK ->2  16QAM -> 4)
% *****************************************************

m2=ml./2;

paradata2=paradata.*2-1;
count2=0;

for jj=1:nd

	isi = zeros(para,1);
	isq = zeros(para,1);

	for ii = 1 : m2 
  		isi = isi + 2.^( m2 - ii ) .* paradata2((1:para),ii+count2);
  		isq = isq + 2.^( m2 - ii ) .* paradata2((1:para),m2+ii+count2);
	end

	iout((1:para),jj)=isi;
	qout((1:para),jj)=isq;

	count2=count2+ml;

end

%******************** end of file ***************************