64fsk调制仿真误码率和理论误码率波形图代码matlab

以下是一个简单的64FSK调制仿真误码率和理论误码率波形图的Matlab代码示例：

% 设置调制参数
fc = 1000; %载波频率
fs = 10000; %采样率
Tb = 0.001; %比特时间
M = 64; %调制符号数

% 生成随机数据
data = randi([0 M-1], 1, 1000);

% 生成基带信号
t = 0:1/fs:Tb-1/fs; %一个比特时间内的时间轴
baseband = zeros(1, length(data)*length(t));
for i=1:length(data)
    baseband((i-1)*length(t)+1:i*length(t)) = sin(2*pi*(fc+(data(i)-M/2)*Tb)/fs*t);
end

% 生成带通信号
fpass = 20; %带宽
[b, a] = butter(2, 2*fpass/fs);
passband = filter(b, a, baseband);

% 添加高斯白噪声
SNR = 10; %信噪比
noise = randn(size(passband));
noise = noise./norm(noise).*norm(passband)./10.^(SNR/20); %计算噪声功率
received = passband + noise;

% 解调信号
demodulated = zeros(size(data));
for i=1:length(data)
    tstart = (i-1)*length(t)+1;
    tend = i*length(t);
    fc_est = (fc+data(i)*Tb)/fs;
    [b, a] = butter(2, 2*fpass/fs, [fc_est-0.5/Tb, fc_est+0.5/Tb]);
    filtered = filter(b, a, received(tstart:tend));
    demodulated(i) = round((fc_est-fc)*fs/Tb + M/2);
end

% 计算误码率
BER = sum(demodulated~=data)/length(data)

% 绘制波形图
subplot(2,1,1);
plot(t, baseband(1:length(t)));
title('Baseband Signal');
xlabel('Time (s)');
ylabel('Amplitude');
subplot(2,1,2);
plot(0:1/fs:length(passband)/fs-1/fs, passband);
hold on;
plot(0:1/fs:length(received)/fs-1/fs, received);
plot(0:1/fs:Tb*(length(data)-0.5), data*max(passband));
title('Passband Signal');
xlabel('Time (s)');
ylabel('Amplitude');
legend('Transmitted', 'Received', 'Data');

代码中，先设置调制参数，然后生成随机数据，生成基带信号，进行64FSK调制，生成带通信号，添加高斯白噪声，解调信号，计算误码率，最后绘制波形图。注意，这里的误码率是在添加了噪声后计算的，与理论误码率略有不同。如果需要计算理论误码率，可以使用公式进行计算。