DPSK調(diào)制解調(diào)的Matlab程序

1、Matlab程序Document serial number【UU89WT-UU98YT-UU8CB-UUUT-UUT108】%DPSK調(diào)制解調(diào)程序清單 %仿真DPSK信號(hào)的產(chǎn)生及相干解調(diào)過(guò)程%將成形濾波器系數(shù)量化為10比特后，寫(xiě)入tra_lpf.coe文件中%將接收濾波器系數(shù)量化為10比特后，寫(xiě)入rec_lpf.coe文件中 %將DPSK已調(diào)數(shù)據(jù)量化為8比特后，寫(xiě)入Dpsk. txt文件中 ps=l*10飛；碼速率為1MHza=0.8;%成形濾波器系數(shù)為0.8B=(1+a)*ps; %中頻信號(hào)處理帶寬Fs=8*10飛；采樣速率為8MHzfc=2*10飛；載波頻率為2MHzN=20000; %

2、仿真數(shù)據(jù)的長(zhǎng)度t=0:1/Fs:(N*Fs/ps-1)/Fs;%產(chǎn)生長(zhǎng)度為N,頻率為fs的時(shí)間序列 s=randint(N,1,2);%產(chǎn)生隨機(jī)數(shù)據(jù)作為原始數(shù)據(jù),%并將絕對(duì)碼變換為相對(duì)碼ds=ones(1,N);for i=2:Nif s(i)=1ds(i)=-ds(i-1);elseds(i)=ds(i-1);end end%對(duì)相對(duì)碼數(shù)據(jù)以Fs頻率采樣Ads=upsample(ds,Fs/ps);%設(shè)計(jì)平方升余弦濾波器n_T=-2 2;rate=Fs/ps;T=1;Shape_b = rcosfir(a,n_T,rate,T);%figure(4);freqz(Shape_b)%對(duì)采樣后的數(shù)

3、據(jù)進(jìn)行升余弦濾波;rcos_Ads=filter(Shape_b,1,Ads);%產(chǎn)生載頻信號(hào)f0=sin(2*pi*fc*t);%產(chǎn)生DPSK已調(diào)信號(hào)dpsk=rcos_Ads.*f0;%與相干載波相乘，實(shí)現(xiàn)相干解調(diào)demod_mult=dpsk.*f0;%設(shè)計(jì)接收端低通濾波器fc=ps 3.1*10八6;%過(guò)渡帶mag=1 0;%窗函數(shù)的理想濾波器幅度dev=0.01 0.01; %紋波 n,wn,beta,ftype=kaiserord(fc,mag,dev,Fs) %獲取凱塞窗參數(shù)%firpm函數(shù)的頻段向fpm=0 fc(1)*2/Fs fc(2)*2/Fs %firpm函數(shù)的頻段向量

4、magpm二1 1 0 0;%firpm 函數(shù)的幅值向量rec_lpf二firpm(n,fpm,magpm);%firpm 函數(shù)返回的最優(yōu)濾波器系數(shù)%對(duì)乘法運(yùn)算后的數(shù)據(jù)進(jìn)行低通濾波，輸出解調(diào)后的基帶信號(hào) demod_lpf=filter(rec_lpf,1,demod_mult);figure(1)%繪制成形濾波后信號(hào)頻譜、DPSK信號(hào)頻譜、DPSK信號(hào)時(shí)域波形m_rcos_Ads=20*log10(abs(fft(rcos_Ads,1024);m_rcos_Ads=m_rcos_ Ads-max(m_rcos_Ads);m_dpsk=20*log10(abs(fft(dpsk,1024);m

5、_dpsk=m_dpsk-max(m_dpsk); %設(shè)置幅頻響應(yīng)的橫坐標(biāo)單位為MHzx_f=0:(Fs/length(m_dpsk):Fs/2;x_f二x_f/106; %只顯示正頻率部分的幅頻響應(yīng)mrcos_Ads=m_rcos_Ads(1:length(x_f);mdpsk=m_dpsk(1:length(x_f);%設(shè)置時(shí)域波表的橫坐標(biāo)單位為usLen=100;%設(shè)置時(shí)域波形顯示的點(diǎn)數(shù)x_t=1:Len;%產(chǎn)生長(zhǎng)度為L(zhǎng)en的時(shí)間序列x_t二x_t/Fs*106%顯示所需的頻譜及時(shí)域波形 subplot(311); plot(x_f,mrcos_Ads);legend(成形濾波后信號(hào)頻譜

6、)；xlabel(頻率(MHz);ylabel(幅度(dB);grid on;subplot(312); plot(x_f,mdpsk);legend(DPSK已調(diào)信號(hào)頻譜)；xlabel(頻率(MHz);ylabel(幅度(dB);grid on;subplot(313); plot(x_t,dpsk(101:Len+100);grid on;legend(DPSK時(shí)域信號(hào)波形)；xlabel(時(shí)間(us);ylabel(幅度(V);grid on;figure(2)%對(duì)相對(duì)碼重復(fù)Fs/ps倍采樣，便于繪圖比較s_Ads=rectpulse(ds,Fs/ps);Len=500;%設(shè)置時(shí)域波形顯示的點(diǎn)數(shù)x_t=l:Len;%產(chǎn)生長(zhǎng)度為L(zhǎng)en的時(shí)間序列x_t二x_t/Fs*106%繪制DPSK解調(diào)前后時(shí)域波形delay=18;%為便于觀察，對(duì)解調(diào)后的基帶波形超前顯示delay個(gè)點(diǎn)。plot(x_t,s_Ads(1:Len)/2,-,x_t,demod_lpf(