main.asv

Rake接收的相关程序

g=19;%二进制转化为十进制
state=1;
N=128  ;       % Number of data bits(bit rate)
noise_offset=0;
chip_rate = 20000  %chip rate
fcarr=20000     %carrier frequency in Hz (0 to 40kHz)
td=[0:Ts:(N*T)-Ts];
[data,data2,Isymbols,Qsymbols]=serial_to_parallel(N);
Isymbols=Isymbols';
Qsymbols=Qsymbols';

[seq1,seq2]=a_prnseq(chip_rate);
%seq1
%seq2
%[pt]=mgen(g,state,chip_rate); %pt是m序列 有两个码片的延时
%pt=2*pt-1;%双极性码
%pt1=chouyang(pt,chip_rate,2);
%seq1=pt1;
%seq2=pt1;
[sig1,sig2]=spreader(Isymbols,Qsymbols,seq1,seq2,N);
%sig1
%sig2

[msumiq,sumiq,cs_t,sn_t,tiq]=qpsk_mod(sig1,sig2,Isymbols,Qsymbols,N,fcarr);
%transmitted signal at this point

[rnd_noise,nb_noise]=noise(sumiq,tiq,N,noise_offset);
nb_noise=0;

no_noise_sumiq=sumiq;sumiq=sumiq+nb_noise;
no_noise_msumiq=msumiq;msumiq=msumiq+nb_noise;
sumiq=conv(sumiq,[1,0,1]);
ssumiq(1)=sumiq(1)+sumiq(40001);
ssumiq(2)=sumiq(2)+sumiq(40002);

for i=3:40000
ssumiq(i)=sumiq(i);
end
sumiq=ssumiq;

%Received signal
%[bit_errs_qpsk,bitout1,bitout2,ycfo1,ycfo2]=demod(msumiq,cs_t,sn_t,tiq,data,N,fcarr);
%[bit_errs_qpsk,bitout1,bitout2,ycfo1,ycfo2]=demod1(msumiq,cs_t,sn_t,tiq,data,N,fcarr);


[bit_errs_ss,i_out,q_out]=despread(tiq,sumiq,cs_t,sn_t,seq1,seq2,data,N,fcarr);
[bit_errs_ss,i_out1,q_out1]=despread1(tiq,sumiq,cs_t,sn_t,seq1,seq2,data,N,fcarr);

i_out=(i_out+i_out1)/2;
q_out=(q_out+q_out1)/2;




bit5=sign(i_out);%+/-1
bit6=sign(q_out);%+/-1

shaped_ibit=bit5 >0;%0 and 1
shaped_qbit=bit6 >0;%0 and 1

i_out=[shaped_ibit]';%transpose
q_out=[shaped_qbit]';%transpose



figure(15)

subplot(2,1,1)
plot(tiq,i_out)
axis([0 20/N -2 2]);
grid on
xlabel('                                                          Time')
ylabel('Amplitude')
title(' I Channel Data')

subplot(2,1,2)
plot(tiq,q_out)
axis([0 20/N -2 2]);
grid on
xlabel('                                                          Time')
ylabel('Amplitude')
title(' Q Channel Data')