matlab编程代做GMSK系统仿真.pdf

1、 function out=delay(data,n,sample_number)%data:延迟的数据%n:延迟码元个数%sample_number:码元采样个数 out=zeros(1,length(data);out(n*sample_number+1:length(data)=data(1:length(data)-n*sample_number);function data_diff=difference(data)%差分编码%*%data 输入信号%data_diff 差分编码后信号%*%-data_diff=zeros(1,length(data);data_diff(1)=1*

2、data(1);%1 为差分编码的初始参考值 for i=2:length(data)data_diff(i)=data_diff(i-1)*data(i);end%*function gt,qt=gauss_filter(Bb,Tb,fs,sample_number)%高斯滤波器%*%Bb 滤波器的 3dB 带宽%Tb 码元时间%fs 采样速率%sample_number 采样个数%*%Rb=16000;%Tb=1/16000;%sample_number=8;%fs=sample_number*Rb;%Bb=0.25/Tb;%-%g(t)irfn=3;%截取 irfn 个 Tb 区间 n=

3、irfn*sample_number;mid=(n./2);t=-mid/fs:1/fs:mid/fs;gt=1/2*(erf(-sqrt(2/log(2)*pi*Bb*(t-1/2*Tb)+erf(sqrt(2/log(2)*pi*Bb*(t+1/2*Tb);%*%-%q(t)qt=zeros(1,irfn*sample_number);for i=1:irfn*sample_number for j=1:i qt(i)=qt(i)+gt(j)/sample_number/2;end;end;%*%GMSK 调制，一比特差分解调 clear all close all%-%参数设置 data

4、_len=30000;%码元个数 sample_number=8;%采样个数 Rb=24000;%码元速率 fc=96000;%载波频率 alpha=0.25;%BbTb 值%*%-%随机产生传输信号 data=rand_binary(data_len);%*%-%GMSK 基带调制 signal_out,I_out,Q_out,phase,gt,qt=mod_gmsk(data,data_len,sample_number,Rb,alpha);%*%-%中频搬移 multi=fc/Rb;I_temp=interp(I_out,multi);Q_temp=interp(Q_out,multi)

5、;Fs=fc*sample_number;t=1/Fs:1/Fs:length(I_temp)*1/Fs;signal_i=I_temp.*cos(2*pi*fc*t);signal_q=Q_temp.*sin(2*pi*fc*t);signal_mod_i=I_temp.*cos(2*pi*fc*t)-Q_temp.*sin(2*pi*fc*t);signal_mod_q=I_temp.*sin(2*pi*fc*t)+Q_temp.*cos(2*pi*fc*t);%*%-%加噪声 for SNR=0:16%signal_mod1=awgn(signal_mod_i+j*signal_mod_

6、q,SNR);noise=randn(1,length(signal_mod_i);b=0.2;c=0.22;d=0.28;e=0.3;F1=0,b,c,d,e,1;A1=0,0,1,1,0,0;bpf=firls(300,F1,A1);noise1=conv(noise,bpf);noise_out=noise1(150+1:150+length(signal_mod_i);Power_noise=sum(noise_out.2);Power_signal_i=sum(signal_mod_i.2);Power_signal_q=sum(signal_mod_q.2);Coe_SNR_i=s

7、qrt(1*Power_signal_i/Power_noise/(10(SNR/10);Coe_SNR_q=sqrt(1*Power_signal_q/Power_noise/(10(SNR/10);signal_mod1=(signal_mod_i+(Coe_SNR_i)*noise_out)+j*(signal_mod_q+(Coe_SNR_q)*noise_out);%加入噪声以后的信号%-%一比特延迟差分 cospart=real(signal_mod1);sinpart=imag(signal_mod1);delay=zeros(1,multi*sample_number)sinp

8、art(1:data_len*sample_number*multi-multi*sample_number);cha=-delay.*cospart;N=300;%滤波器的阶数为(N+1)F=0,fc,fc,Fs/2*2/Fs;A=1,1,0,0;lpf=firls(N,F,A);dem1=conv(cha,lpf);dem=dem1(N/2+1:N/2+length(cha);%*%-%抽样判决 for i=1:data_len demod_data(i)=dem(i*multi*sample_number)0;end demod_data=2*demod_data-1;%*%-%计算误码

9、率 num,ber(SNR+1)=symerr(demod_data(2:data_len),data(2:data_len);%*end%*%-%误码率曲线 semilogy(0:16,ber,r*-);%*%GMSK 调制，一比特差分解调 clear all close all%-%参数设置 data_len=30000;%码元个数 sample_number=8;%采样个数 Rb=24000;%码元速率 fc=96000;%载波频率 alpha=0.25;%BbTb 值%*%-%随机产生传输信号 data=rand_binary(data_len);%*%-%GMSK 基带调制 sign

10、al_out,I_out,Q_out,phase,gt,qt=mod_gmsk(data,data_len,sample_number,Rb,alpha);%*%-%中频搬移 multi=fc/Rb;I_temp=interp(I_out,multi);Q_temp=interp(Q_out,multi);Fs=fc*sample_number;t=1/Fs:1/Fs:length(I_temp)*1/Fs;signal_i=I_temp.*cos(2*pi*fc*t);signal_q=Q_temp.*sin(2*pi*fc*t);signal_mod_i=I_temp.*cos(2*pi*

11、fc*t)-Q_temp.*sin(2*pi*fc*t);signal_mod_q=I_temp.*sin(2*pi*fc*t)+Q_temp.*cos(2*pi*fc*t);%*amp=1 0 0.69 0 0.24;dj=length(amp);for i=1:dj signal_mod_i=signal_mod_i+amp(i)*delay(signal_mod_i,i-1,sample_number);signal_mod_q=signal_mod_q+amp(i)*delay(signal_mod_q,i-1,sample_number);end%-%加噪声 for SNR=0:16

12、%signal_mod1=awgn(signal_mod_i+j*signal_mod_q,SNR);noise=randn(1,length(signal_mod_i);b=0.2;c=0.22;d=0.28;e=0.3;F1=0,b,c,d,e,1;A1=0,0,1,1,0,0;bpf=firls(300,F1,A1);noise1=conv(noise,bpf);noise_out=noise1(150+1:150+length(signal_mod_i);Power_noise=sum(noise_out.2);Power_signal_i=sum(signal_mod_i.2);Po

13、wer_signal_q=sum(signal_mod_q.2);Coe_SNR_i=sqrt(1*Power_signal_i/Power_noise/(10(SNR/10);Coe_SNR_q=sqrt(1*Power_signal_q/Power_noise/(10(SNR/10);signal_mod1=(signal_mod_i+(Coe_SNR_i)*noise_out)+j*(signal_mod_q+(Coe_SNR_q)*noise_out);%加入噪声以后的信号%-%一比特延迟差分 cospart=real(signal_mod1);sinpart=imag(signal_

14、mod1);delay=zeros(1,multi*sample_number)sinpart(1:data_len*sample_number*multi-multi*sample_number);cha=-delay.*cospart;N=300;%滤波器的阶数为(N+1)F=0,fc,fc,Fs/2*2/Fs;A=1,1,0,0;lpf=firls(N,F,A);dem1=conv(cha,lpf);dem=dem1(N/2+1:N/2+length(cha);%*%-%抽样判决 for i=1:data_len demod_data(i)=dem(i*multi*sample_numb

15、er)0;end demod_data=2*demod_data-1;%*%-%计算误码率 num,ber(SNR+1)=symerr(demod_data(2:data_len),data(2:data_len);%*end%*%-%误码率曲线 semilogy(0:16,ber,r*-);%*%GMSK 调制，一比特差分解调 clear all close all%-%参数设置 data_len=30000;%码元个数 sample_number=8;%采样个数 Rb=24000;%码元速率 fc=96000;%载波频率 alpha=0.25;%BbTb 值%*%-%随机产生传输信号 da

16、ta=rand_binary(data_len);%*%-%GMSK 基带调制 signal_out,I_out,Q_out,phase,gt,qt=mod_gmsk(data,data_len,sample_number,Rb,alpha);%*%-%中频搬移 multi=fc/Rb;I_temp=interp(I_out,multi);Q_temp=interp(Q_out,multi);Fs=fc*sample_number;t=1/Fs:1/Fs:length(I_temp)*1/Fs;signal_i=I_temp.*cos(2*pi*fc*t);signal_q=Q_temp.*sin(2*pi*fc*t);signal_mod_i=I_temp.*cos(2*pi*fc*t)-Q_temp.*sin(2*pi*fc*t);signal_mod_q=I_temp.*sin(2*pi*fc*t)+Q_temp.*cos(2*pi*fc*t);%*fc=fc+500;%-%加噪声 for SNR=0:20%signal_mod1=awgn(signal_mod_i+j*sign