function?out?=?qam16（in?modem）
%Qam16		16QAM?modulation?and?demodulation?（hard?output）?for?IEEE802.11.
%?Inputs	in?--?column?vector;
%		modem?=?1?--?modulation?=?others?--?demodulation.
%?Output	out?--?column?vector.

%?Last?modified?by?Jianhua?Liu?（SAL?UF）?on?June?2?2001

N?=?length（in）;

if?modem?==?1??????????%?do?modulation
???if?~（rem（N4）==0）
??????error（‘Error:?Input?length?should?be?a?multiple?of?4‘）
???end
???
???NN?=?N/4;
???out?=?zeros（NN1）;
???
???for?i?=?1?:?NN
??????bits?=?in（4*i-3:4*i）;
??????if????????bits（1:2）?==?[0;?0]?Inphase?=?-3;
?????????elseif?bits（1:2）?==?[0;?1]?Inphase?=?-1;
?????????elseif?bits（1:2）?==?[1;?1]?Inphase?=??1;
?????????elseif?bits（1:2）?==?[1;?0]?Inphase?=??3;
?????????else????????????????????????error（‘Wrong?data?bits‘