基于matlab的qpsk傳輸系統(tǒng)(編輯修改稿)
2025-07-21 15:35 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 a(i)=input(i)=1。elseinput(i)=0。endend%Series to Parallelfor i=1:dataif rem(i,2)==1 if input(i)==1 I(i)=1。 I(i+1)=1。else I(i)=1。 I(i+1)=1。endelseif input(i)==1Q(i1)=1。Q(i)=1。elseQ(i1)=1。Q(i)=1。endendend% Zero insertionzero=5。 % Sampling rate is 25MHzfor i=1:zero*dataif rem(i,zero)==1Izero(i)=I(fix((i1)/zero)+1)。Qzero(i)=Q(fix((i1)/zero)+1)。elseIzero(i)=0。Qzero(i)=0。endend%Pulse shaping filterNT =50。N=2*zero*NT。Fs=25e6。rf=。psf=rcosfir(rf,NT,zero,Fs,39。sqrt39。)。Ipulse= conv(Izero,psf)。Qpulse= conv(Qzero,psf)。%Modulationfor i=1:zero*data+Nt(i)=(i1)/(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。%% QPSK Receiver%% Demodulationfor i=1:zero*data+NIdem(i)=sum(i).*sqrt(2)*cos(2*pi*Fc*t(i))。Qdem(i)=sum(i).*(sqrt(2)*sin(2*pi*Fc*t(i)))。end% Matched filtermtf= rcosfir(rf,NT, zero,Fs,39。sqrt39。)。Imat = conv(Idem,mtf)。Qmat = conv(Qdem,mtf)。% Data selectionfor i=1:zero*dataIsel(i)=Imat(i+N)。Qsel(i)=Qmat(i+N)。end% Samplerfor i = 1:dataIsam(i)= Isel((i1)*zero+1)。Qsam(i)= Qsel((i1)*zero+1)。end% Decision thresholdthreshold = 。for i = 1:dataif Isam(i)= thresholdIfinal(i)= 1。elseIfinal(i)= 1。endif Qsam(i) = thresholdQfinal(i) = 1。elseQfinal(i)= 1。endend% Parallel to Seriesfor i = 1:dataif rem(i, 2)== 1if Ifinal(i)== 1final(i)=1。elsefinal(i)= 0。endelseif Qfinal(i) == 1final(i)= 1。elsefinal(i)= 0。endendendfigure(1)plot(20*log(abs(fft(input))))axis([0 data 40 100])gridtitle(39。Spectrum of Input binary data39。)figure(2)subplot(221)plot(20*log(abs(fft(I))))axis([0 data 40 140])gridtitle(39。Spectrum of Ichannel data39。)subplot(222)plot(20*log(a
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