mod_demod.rar_64 QAM MODEM_64QAM调制解调_Bpsk_demod matlab_bpsk 调制解调

function demod_out = demodulation(demod_in,mod_mode) %%************************************************************************* %%Function information: %%由信道信号的复数值解调对应的二进制序列(In this program,the channel value are demodulated.) %%------------------------------------------------------------------------- %%First time : 3/25/2002 %%Newest modified time:6/20/2002 %%Programmer:Xuewei Mao %%Version: 0.2 %%------------------------------------------------------------------------- %%************************************************************************* %%************************************************************************* %% Reference: %%------------------------------------------------------------------------- %% %%------------------------------------------------------------------------- %% Note: %%------------------------------------------------------------------------- %% Here,the method for the four modulation modes is the same ,so see the note %%for QPSK, and the note for the other three is omitted. %%------------------------------------------------------------------------- %% Function discription: %%------------------------------------------------------------------------- %% 由信道信号的复数值找出对应的二进制序列。方法如下：由信道值， %%求出该值与星座图中所有点的距离，找出距离最小的点，该点对应的 %%二进制序列及为该信道对应的解调结果。 %% In this program,the channel value are demodulated. %% The process: firstly,calculate the distance between the channel value %% and all the constellation points.then,find the shortest distance,thus ,the point %% is the one.At last,put out the binary sequence symbolizing the point. %%------------------------------------------------------------------------- %% Input: %%------------------------------------------------------------------------- %% demod_in :输入信道值 (the input channel value) %%------------------------------------------------------------------------- %% Output: %%------------------------------------------------------------------------- %% demod_out:解调结果 (demodulation output(binary) ) %%------------------------------------------------------------------------- %% Global Variable: %%------------------------------------------------------------------------- %% g_RT %%------------------------------------------------------------------------- %%************************************************************************* %system_parameters switch (mod_mode) case 2 %BPSK modulation demod_out=zeros(1,length(demod_in)); for i=1:length(demod_in) if abs( demod_in(i)-1)-abs( demod_in(i)+1)<=0 %demod_in(i)-1:接收点到1的距离; demod_in(i)+1:接收点到-1的距离 demod_out(i)=1; else demod_out(i)=0; end end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% case 4 %QPSK modulation d=zeros(4,length(demod_in)); % 'd ' is the distance between the channel value and the constellation point m=zeros(1,length(demod_in)); temp=[-1-j -1+j 1-j 1+j]/sqrt(2); for i=1:length(demod_in) for n=1:4 %下面的demod_in(i)为啥要乘以sqrt(2)? --yzh d(n,i)=(abs(demod_in(i)*sqrt(2)-temp(n))).^2;%由信道值，求出该值与星座图中所有点的距离 end %calculate the distance between the channel and the constellation points [min_distance,constellation_point] = min(d(:,i)) ; %D(:,i)=sort(d(:,i));%排序 (sort the distance in ascending order.) m(i) = constellation_point; end A=de2bi([0:3],'left-msb');%写出0到N-1(N为星座图点数) %(converts a nonnegative decimal vector [0,3] to a binary matrix A.) for i=1:length(demod_in) DEMOD_OUT(i,:)=A(m(i),:); %matrix:length(demod_in)*2 --yzh % 最小值对应的星座点序号的二进制表示即为解调结果 end demod_out=reshape(DEMOD_OUT',1,length(demod_in)*2); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% case 16 d=zeros(16,length(demod_in)); b=ones(1,length(demod_in)); m=zeros(1,length(demod_in)); temp=[-3-3*j -3-j -3+3*j -3+j ... -1-3*j -1-j -1+3*j -1+j ... 3-3*j 3-j 3+3*j 3+j ... 1-3*j 1-j 1+3*j 1+j]/sqrt(10); for i=1:length(demod_in) for n=1:16 %下面的demod_in(i)为啥又不需要乘以sqrt(10)? --yzh d(n,i)=(abs(demod_in(i)*sqrt(10)-temp(n))).^2; %加上sqrt(10)，与其他解调对应 --yzh end [min_distance,constellation_point] = min(d(:,i)) ; %D(:,i)=sort(d(:,i));%排序 (sort the distance in ascending order.) m(i) = constellation_point; end A=de2bi([0:15],'left-msb'); for i=1:length((demod_in)) DEMOD_OUT(i,:)=A(m(i),:); end demod_out=reshape(DEMOD_OUT',1,length(demod_in)*4); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% case 64 %64_QAM d=zeros(64,length(demod_in)); D=zeros(64,length(demod_in)); m=zeros(1,length(demod_in)); temp=[-7-7*j -7-5*j -7-j -7-3*j -7+7*j -7+5*j -7+j -7+3*j... -5-7*j -5-5*j -5-j -5-3*j -5+7*j -5+5*j -5+j -5+3*j... -1-7*j -1-5*j -1-j -1-3*j -1+7*j -1+5*j -1+j -1+3*j... -3-7*j -3-5*j -3-j -3-3*j -3+7*j -3+5*j -3+j -3+3*j... 7-7*j 7-5*j 7-j 7-3*j 7+7*j 7+5*j 7+j 7+3*j... 5-7*j 5-5*j 5-j 5-3*j 5+7*j 5+5*j 5+j 5+3*j... 1-7*j 1-5*j 1-j 1-3*j 1+7*j 1+5*j 1+j 1+3*j... 3-7*j 3-5*j 3-j 3-3*j 3+7*j 3+5*j 3+j 3+3*j ]/sqrt(42); for i=1:length(demod_in) for n=1:64 d(n,i)=(abs(demod_in(i)*sqrt(42)-temp(n))).^2; end [min_distance,constellation_point] = min(d(:,i)) ; %D(:,i)=sort(d(:,i));%排序 (sort the distance in ascending order.) m(i) = constellation_point; end A=de2bi([0:63],'left-msb'); for i=1:length(demod_in) DEMOD_OUT(i,:)=A(m(i),:); end demod_out=reshape(DEMOD_OUT',1,length(demod_in)*6); otherwise disp('Error! Please input again'); end