Cedric Roux
56c66c09aa
Pre-ci test passed git-svn-id: http://svn.eurecom.fr/openair4G/trunk@4000 818b1a75-f10b-46b9-bf7c-635c3b92a50f
101 lines
2.1 KiB
Matlab
Executable File
101 lines
2.1 KiB
Matlab
Executable File
function [ratio,phi_est]=IQ_estimation(freq)
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gpib_card=0; % first GPIB PCI card in the computer
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sme=28; % this is configured in the signal generator Utilities->System->GPIB->Address menu (for SME)
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gpib_send(gpib_card,sme,'*RST;*CLS'); % reset and configure the signal generator
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sleep(.1);
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gpib_send(gpib_card,sme,'POW -63dBm');
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disp(freq)
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gpib_send(gpib_card,sme,strcat('FREQ ',int2str(freq),'MHz'));
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gpib_send(gpib_card,sme,'OUTP:STAT ON'); % activate output
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cmd1='/homes/nussbaum/openair1/ARCH/LEON3/hostpc/user/tools/scripts/set_receiver -M ';
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gain1=61;
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gain2=61;
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frequency=int2str(freq);
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cmd=strcat(cmd1,frequency,' -g1 ',int2str(gain1),' -g2 ',int2str(gain2));
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system(cmd);
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sleep(.1);
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s=oarf_get_frame(0);
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signal=s(:,1);
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size_data=20480;
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Fs=7680; %in kHz
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band = 2000; %in kHz
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max_pos=0;
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max=0;
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f=abs(fft(signal)).^2;
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for n=2:size_data
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if(f(n) > max)
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max=f(n);
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max_pos=n;
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end;
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end;
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disp(max_pos)
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freq_max=Fs/size_data*max_pos - Fs/2 % corresponding frequency
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if(abs(freq_max-2000)>100)
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disp('Warning')
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end;
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cumI=0;
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cumQ=0;
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I=real(signal(1:2000));
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Q=imag(signal(1:2000));
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for i=1:2000
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cumI=cumI + I(i)*I(i);
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cumQ=cumQ + Q(i)*Q(i);
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end;
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amp= sqrt(2*cumI/length(I))
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I=I/amp;
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Q=Q/amp;
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ratio=sqrt(cumI/cumQ)
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n_fft=1024;
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f=abs(fft(I(1:n_fft)));
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max = 0;
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index=0;
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for i=1:n_fft/2
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if f(i)> max
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max=f(i);
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index=i;
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end;
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end;
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disp(max)
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disp(index)
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%figure
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%plot(20*log10(abs(f)));
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freq_estim=(index-1)/n_fft;
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p=Q*ratio.*I;
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sinphi=2*sum(p)/length(Q);
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phi_est=-asin(sinphi)
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Qcor=(sin(phi_est)*I+ratio*Q)/cos(phi_est);
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%figure
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%plot(I(1:100))
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%hold on
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%plot(Qcor(1:100),'g');
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comp=I+j*Qcor;
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%hold off
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%figure
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%plot(20*log10(abs(fft(comp))));
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endfunction;
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% per=round(1/freq_estim)
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% figure;plot(I(1:per+1))
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% opt_offset=-5
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% min_diff=10^20;
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% for offset=0:per
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% diff=0;
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% for k=1:n_fft
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% diff=diff+abs(I(k+offset)-Q(k));
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% end;
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% if diff<min_diff
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% min_diff=diff;
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% opt_offset= offset;
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% end;
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% end;
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% disp(opt_offset)
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% % normally, as to be 3/4*per
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% opt_offset=opt_offset-3*per/4;
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% disp(opt_offset/per*2*pi)
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