qdpsk程序matlab

1、Matlab程序：%-QDPSK-clear all;close all;clc;%-%参数设置Fc = 5e6;data_len=10000; %-%随机产生传输信号rand_data_len =randn(1,data_len);for i=1:data_len if rand_data_len(i)>=0.5 input(i)=1; else input(i)=0; endend%-%串并转换for i=1:data_len if rem(i,2)=1 if input(i)=1 I(i)=-1; I(i+1)=-1; else I(i)=1; I(i+1)=1; end else

2、 if input(i)=1 Q(i-1)=-1; Q(i)=-1; else Q(i-1)=1; Q(i)=1; end endend%-% 码变换I_diff=zeros(1,data_len);Q_diff=zeros(1,data_len);I_diff(1)=I(1);Q_diff(1)=Q(1);for i=2:data_len if I(i)=1&&Q(i)=1 % 0->+1 1->-1 if I_diff(i-1)=1&&Q_diff(i-1)=1 I_diff(i)=1; Q_diff(i)=1; elseif I_diff(i-

3、1)=-1&&Q_diff(i-1)=1 I_diff(i)=-1; Q_diff(i)=1; elseif I_diff(i-1)=-1&&Q_diff(i-1)=-1 I_diff(i)=-1; Q_diff(i)=-1; else I_diff(i)=1; Q_diff(i)=-1; end elseif I(i)=-1&&Q(i)=1 if I_diff(i-1)=1&&Q_diff(i-1)=1 I_diff(i)=-1; Q_diff(i)=1; elseif I_diff(i-1)=-1&&Q_dif

4、f(i-1)=1 I_diff(i)=-1; Q_diff(i)=-1; elseif I_diff(i-1)=-1&&Q_diff(i-1)=-1 I_diff(i)=1; Q_diff(i)=-1; else I_diff(i)=1; Q_diff(i)=1; end elseif I(i)=-1&&Q(i)=-1 if I_diff(i-1)=1&&Q_diff(i-1)=1 I_diff(i)=-1; Q_diff(i)=-1; elseif I_diff(i-1)=-1&&Q_diff(i-1)=1 I_diff(i)=

5、1; Q_diff(i)=-1; elseif I_diff(i-1)=-1&&Q_diff(i-1)=-1 I_diff(i)=1; Q_diff(i)=1; else I_diff(i)=-1; Q_diff(i)=1; end else if I_diff(i-1)=1&&Q_diff(i-1)=1 I_diff(i)=1; Q_diff(i)=-1; elseif I_diff(i-1)=-1&&Q_diff(i-1)=1 I_diff(i)=1; Q_diff(i)=1; elseif I_diff(i-1)=-1&&Q

6、_diff(i-1)=-1 I_diff(i)=-1; Q_diff(i)=1; else I_diff(i)=-1; Q_diff(i)=-1; end endend%-%零内插zero=5; % 采样率为25MHz for i=1:zero*data_len if rem(i,zero)=1 Izero(i)=I_diff(fix(i-1)/zero)+1); Qzero(i)=Q_diff(fix(i-1)/zero)+1); else Izero(i)=0; Qzero(i)=0; endend%-%脉冲成形滤波器NT =50;N=2*zero*NT;Fs=25e6;rf=0.1;ps

7、f=rcosfir(rf,NT,zero,Fs,'sqrt'); Ipulse= conv(Izero,psf);Qpulse= conv(Qzero,psf);%-%调制for i=1:zero*data_len+N t(i)=(i-1)/(Fc*zero); Imod(i)=Ipulse(i).*sqrt(2)*cos(2*pi*Fc*t(i); Qmod(i)=Qpulse(i).*(-sqrt(2)*sin(2*pi*Fc*t(i);endsum=Imod+Qmod;%-%加噪声for SNR=0:10 sum1 = awgn(sum,SNR);%-%解调%-%相乘器f

8、or i=1:zero*data_len+N Idem(i)=sum1(i).*sqrt(2)*cos(2*pi*Fc*t(i); Qdem(i)=sum1(i).*(-sqrt(2)*sin(2*pi*Fc*t(i);end%-%匹配滤波器mtf= rcosfir(rf,NT, zero,Fs,'sqrt');Imat = conv(Idem,mtf);Qmat = conv(Qdem,mtf);%-%抽取for i=1:zero*data_len Isel(i)=Imat(i+N); Qsel(i)=Qmat(i+N);end%-%采样for i = 1:data_len

9、Isam(i)= Isel(i-1)*zero+1); Qsam(i)= Qsel(i-1)*zero+1);end %-%判决threshold = 0.2;for i = 1:data_len if Isam(i)>= threshold I_final(i)= 0; else I_final(i)= 1; end if Qsam(i) >= threshold Q_final(i) = 0; else Q_final(i)= 1; endend%-% 码反变换I_abs=zeros(1,data_len);Q_abs=zeros(1,data_len);I_abs(1)=I_

10、final(1);Q_abs(1)=Q_final(1);for i=2:data_len if I_final(i-1)=0&&Q_final(i-1)=0 %前一输入双比特为00 if I_final(i)=0&&Q_final(i)=0 %本时刻输入00 I_abs(i)=0; Q_abs(i)=0; %输出数据00 elseif I_final(i)=0&&Q_final(i)=1 %本时刻输入01 I_abs(i)=0; Q_abs(i)=1; %输出数据01 elseif I_final(i)=1&&Q_final(i

11、)=1 %本时刻输入11 I_abs(i)=1; Q_abs(i)=1; %输出数据11 else %本时刻输入10 I_abs(i)=1; Q_abs(i)=0; %输出数据10 end elseif I_final(i-1)=0&&Q_final(i-1)=1 %前一输入双比特为01 if I_final(i)=0&&Q_final(i)=0 %本时刻输入00 I_abs(i)=1; Q_abs(i)=0; %输出数据10 elseif I_final(i)=0&&Q_final(i)=1 %本时刻输入01 I_abs(i)=0; Q_abs

12、(i)=0; %输出数据00 elseif I_final(i)=1&&Q_final(i)=1 %本时刻输入11 I_abs(i)=0; Q_abs(i)=1; %输出数据01 else %本时刻输入10 I_abs(i)=1; Q_abs(i)=1; %输出数据11 end elseif I_final(i-1)=1&&Q_final(i-1)=1 %前一输入双比特为11 if I_final(i)=0&&Q_final(i)=0 %本时刻输入00 I_abs(i)=1; Q_abs(i)=1; %输出数据11 elseif I_final(

13、i)=0&&Q_final(i)=1 %本时刻输入01 I_abs(i)=1; Q_abs(i)=0; %输出数据10 elseif I_final(i)=1&&Q_final(i)=1 %本时刻输入11 I_abs(i)=0; Q_abs(i)=0; %输出数据00 else %本时刻输入10 I_abs(i)=0; Q_abs(i)=1; %输出数据01 end else %前一输入双比特为10 if I_final(i)=0&&Q_final(i)=0 %本时刻输入00 I_abs(i)=0; Q_abs(i)=1; %输出数据01 els

14、eif I_final(i)=0&&Q_final(i)=1 %本时刻输入01 I_abs(i)=1; Q_abs(i)=1; %输出数据11 elseif I_final(i)=1&&Q_final(i)=1 %本时刻输入11 I_abs(i)=1; Q_abs(i)=0; %输出数据10 else %本时刻输入10 I_abs(i)=0; Q_abs(i)=0; %输出数据00 end endend%-%并串转换for i = 1:data_len if rem(i, 2)= 1 if I_abs(i)= 1 final(i)=1; else final(i)=0; end else if Q_abs(i) = 1 final(i)=1; else final(i)=0; end endend%-%计算误码率