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1、function ber = sim_ASK2(snrIndB,N,flag)% 二进制ASK调制解调仿真程序% 输入% snr: 信噪比% N: 仿真比特数% flag:绘制调制解调波形标志位% 输出% y: 误码率x = round(rand(1,N);% 产生信号比特fc = 200; % 载波频率fs = 2000;% 采样频率fb = 50; % 比特频率nSamples = fs/fb;% 每比特采样数signal_in_one_bit = cos(2*pi*fc*(0:nSamples-1)/fs);% 传号space_in_one_bit = zeros(1,nSamples)
2、; % 空号limitation = sum(signal_in_one_bit.2)/2; % 判决门限sig_ori = reshape(repmat(x,nSamples,1),1,N*nSamples); % 原始信号% ASK调制y=zeros(1,nSamples*N);for i=1:length(x) if(x(i)=1) y(i-1)*nSamples+1:i*nSamples) = signal_in_one_bit; else y(i-1)*nSamples+1:i*nSamples) = space_in_one_bit; endendmod_sig = y;% 调制信
3、号% 高斯信号传输% rec_sig = awgn(mod_sig,snr,0); % 通过高斯信道后的接收信号snr = 10(0.1*snrIndB)/(fb/4);sigma = 1/sqrt(snr);rec_sig = awgn_gauss(mod_sig,sigma);% ASK解调bits_judged = zeros(1,N); for i = 1:N % 逐比特处理 rec_seg = rec_sig(i-1)*nSamples+1:(i*nSamples); sum_rec = rec_seg*signal_in_one_bit; % 相关累积 if(sum_rec=lim
4、itation) % 判决 bits_judged(i) = 1; else bits_judged(i) = 0; end end x_pie = bits_judged;% 接收信号判决值 ber = length(find(x=x_pie)/N;% 误码率 % 绘制调制解调结果图if(1=flag) bits_display = 30;% 绘图显示的比特数 figure; subplot(411);stem(x(1:bits_display);title(原始数据比特),xlabel(t) subplot(412);plot(mod_sig(1:bits_display*nSamples
5、);title(调制信号),xlabel(t) subplot(413);plot(rec_sig(1:bits_display*nSamples);title(经过信道后的接收信号),xlabel(t) subplot(414);stem(x_pie(1:bits_display);title(解调以后的数据比特),xlabel(t) % 计算和绘制信号频谱 f1,powerIndB1 = getFre(sig_ori,fs); f2,powerIndB2 = getFre(mod_sig,fs); f3,powerIndB3 = getFre(rec_sig,fs); figure sub
6、plot(311);plot(f1,powerIndB1); xlim(0 fs/2);ylim(-80 10);title(原始数据的功率谱密度);xlabel(频率(Hz);ylabel(功率谱密度（w/Hz）); subplot(312);plot(f2,powerIndB2); xlim(0 fs/2);ylim(-80 10);title(调制信号的功率谱密度);xlabel(频率(Hz);ylabel(功率谱密度(w/Hz); subplot(313);plot(f3,powerIndB3); xlim(0 fs/2);ylim(-80 10);title(经过信道接收信号的功率谱密度);xlabel(频率(Hz);ylabel(功率谱密度(w/Hz);end