clc

clear all

%---------扩频通信过程---------------

%---------只仿真一个频点的情况---------------

%---------初始化---------------

Ts=0.00001; fs=1/Ts;

EndTime=2-Ts; %2s

%---------产生信息序列(双极性不归零码)---------------

Tm=0.25; fm=1/Tm; %码率

[u,time] = gensig('square',2*Tm,EndTime,Ts);

y = 2*(u-0.5);

figure(1);

plot(time,y);

title('信息序列');

xlabel('time (seconds)');

axis([0 2 -2 2]);

%---------FSK调制---------------

T0=0.1; f0=1/T0;

T1=0.2; f1=1/T1;

[u0,time]=gensig('sin',T0,EndTime,Ts);

[u1,time]=gensig('sin',T1,EndTime,Ts);

y0=u0.*sign(-y+1);

y1=u1.*sign(y+1);

SignalFSK=y0+y1; % FSK信号

%---------FSK调制的频谱---------------

nfft=fs+1;

Y = fft(SignalFSK,nfft);

PSignalFSK = Y.* conj(Y)/nfft;

f = fs*(0:nfft/2)/nfft;

figure(2);

plot(f,PSignalFSK(1:nfft/2+1));

title('FSK调制后的频谱');

xlabel('frequency (Hz)');

axis([0 100 -inf inf]);

%---------FSK调制后，低通滤波---------------

cof_low=fir1(64,25/fs);

SignalFSK_l=filter(cof_low,1,SignalFSK);

figure(3);

plot(time,SignalFSK_l);

title('FSK调制后经过低通滤波的波形');

xlabel('time (seconds)');

axis([0 2 -2 2]);

YSignalFSK_l = fft(SignalFSK_l,nfft);

PSignalFSK_l = YSignalFSK_l.* conj(YSignalFSK_l)/nfft;

f = fs*(0:nfft/2)/nfft;

figure(4);

plot(f,PSignalFSK_l(1:nfft/2+1));

title('FSK调制后经过低通滤波的频谱');

xlabel('frequency (Hz)');

axis([0 100 -inf inf]);

%---------混频--------------

fc=1000;Tc=1/fc; %频点: 1000

[Carrier,time] = gensig('sin',Tc,EndTime,Ts); %产生扩频载波

MixSignal=SignalFSK_l.*Carrier;

figure(6);

plot(time,MixSignal);

title('混频后的波形');

xlabel('time (seconds)');

axis([0 2 -2 2]);

%---------带通滤波--------

cof_band=fir1(64,[fc-12.5,fc+12.5]/fs);

yMixSignal=filter(cof_band,1,MixSignal);

figure(7);

plot(time,yMixSignal);

title('经过带通滤波的混频信号');

xlabel('time (seconds)');

axis([0 2 -2 2]);

YMixSignal = fft(yMixSignal,nfft);

PMixSignal = YMixSignal.* conj(YMixSignal)/nfft;

f = fs*(0:nfft/2)/nfft;

figure(8);

plot(f,PMixSignal(1:nfft/2+1));

title('经过带通滤波的混频信号频谱');

xlabel('frequency (Hz)');

axis([800 1200 -inf inf]);

%----------传输信道--------------

Sign_send=yMixSignal;

Sign_rec=Sign_send;

%----------传输信道---------------

%----------接收端---------------

%----------解扩----------------

fc=1000;Tc=1/fc;

[Carrier,time]=gensig('sin',Tc,EndTime,Ts); %产生扩频载波

Sign_rec=Sign_send;

ySign_rec=Sign_rec.*Carrier;

figure(9);

plot(time,ySign_rec);

title('解扩后的信号');

xlabel('time (seconds)');

axis([0 2 -1 1]);

%----------低通滤波,取下边频------------

yrr=ySign_rec;

cof_low=fir1(64,25/fs);

Sign_rec_l=filter(cof_low,1,ySign_rec);

figure(10);

plot(time,Sign_rec_l);

title('解扩后的下边频的信号');

xlabel('time (seconds)');

axis([0 2 -1 1]);

YSign_rec_l = fft(Sign_rec_l,nfft);

PSign_rec_l = YSign_rec_l.* conj(YSign_rec_l)/nfft;

f = fs*(0:nfft/2)/nfft;

figure(11);

plot(f,PSign_rec_l(1:nfft/2+1));

title('解扩后的下边频频谱');

xlabel('frequency (Hz)');

axis([0 100 -inf inf]);

%----------FSK译码--------------

cof_f0=fir1(64,[f0-0.25,f0+0.25]/fs);

cof_f1=fir1(64,[f1-0.25,f1+0.25]/fs);

DeFSK0=filter(cof_f0,1,Sign_rec_l);

DeFSK1=filter(cof_f1,1,Sign_rec_l);

rDeFSK0=DeFSK0.*u0;

rDeFSK1=DeFSK1.*u1;

rDeFSK=rDeFSK0-rDeFSK1;

figure(12);

plot(time,rDeFSK);

title('采样判决前的信号');

xlabel('time (seconds)');

axis([0 2 -2 2]);

%-----------采样判决---------------

Sampletime=0.25/Ts;

Message=[];

Num=0;

while(Num<2/Ts)

if(mod(Num,Sampletime)==0)

Message=[Message ones(1,Sampletime+1)*sign(sum(rDeFSK((Num+1):(Num+Sampletime))))];

end

Num=Num+Sampletime;

end

figure(13);

plot((1:length(Message))/fs,Message);

title('恢复的信息');

xlabel('time (seconds)');

axis([0 2 -2 2]);

%---------产生8位m序列，控制频率合成器产生频率变化的高频载波---------------

clear all;

clc;

%---------初始化---------------

MAXCLOCK=1000000; %步长是0.01ms

PNSeq=[0 0 0 0 0 0 0 1];

PNSeq1=[0 0 0 1 0 0 1 1];

InitialPNSeq=PNSeq;

InitialPNSeq1=PNSeq1;

PNSeqNum=1; %第几次选择频率

SaveFrq=[];

SaveFrq1=[];

%---------主仿真时钟---------------

CLOCK=0; %单位是 ms/100

step=5000; %每100表示1ms

%---------产生M序列---------------

sim('SimCreatMSeq');

%---------仿真开始---------------

while CLOCK < MAXCLOCK

CLOCK=CLOCK+step;

If mod(CLOCK,5000)==0

%---------产生M序列---------------

% 5 ms跳一次频, 每秒200跳

%---------选择频率---------------

MixFrq=SelectFrq(PNSeq(PNSeqNum:PNSeqNum+7))/1000e3;

MixFrq1=SelectFrq(PNSeq1(PNSeqNum:PNSeqNum+7))/1000e3;

PNSeqNum=PNSeqNum+1;

SaveFrq=[SaveFrq MixFrq];

SaveFrq1=[SaveFrq1 MixFrq1];

end

%结果画图

figure(1);

for i=1:length(SaveFrq)

plot(i/200,SaveFrq(i)/10,'s');

plot(i/200,SaveFrq1(i)/10,'x');

hold on;

end

title('跳频点的变化情况');

xlabel('time (seconds)');

ylabel('frequence (MHz)');

axis([0 1 89 90]);

%---------根据m序列的8位状态，选择频率---------------

function Frq=SelectFrq(Code)

tempCode=128*Code(8)+64*Code(7)+32*Code(6)+16*Code(5)+8*Code(4)+4*Code(3)+2*Code(2)+Code(1);

if(tempCode>200);

tempCode=tempCode-128;

end

MaxFrq=94*1e6;

MinFrq=88*1e6;

Frq=(MaxFrq-MinFrq)/200*(tempCode-0)/2+MinFrq; %(MaxFrq-MinFrq)/200=30;

这个程序90%都是对的，但是运行起来就是不行，我是急着做啊，对MATLAB就是一无所知啊！求指导啊！感激不尽，真心急！