matlab 扫频扩频载波调制代码

以下是一个简单的MATLAB代码，用于实现扫频扩频载波调制：

% 设置参数
fc = 1000; % 载波频率
f0 = 100; % 扫频起始频率
f1 = 10000; % 扫频终止频率
T = 1; % 信号持续时间
fs = 44100; % 采样率
SNR = 10; % 信噪比

% 生成扫频信号
t = 0:1/fs:T-1/fs;
f = linspace(f0, f1, length(t));
sweep = cos(2*pi*cumsum(f)/fs);

% 生成随机扩频序列
chipSeq = randi([0 1], length(t), 10);
spread = repmat(chipSeq, 1, length(t)/10);

% 扩频
spreadSignal = sweep .* spread;

% 调制
modulatedSignal = spreadSignal .* cos(2*pi*fc*t);

% 添加噪声
noise = randn(size(modulatedSignal));
noisySignal = modulatedSignal + 10^(-SNR/20)*std(modulatedSignal)*noise;

% 绘制信号图像
figure;
subplot(311);
plot(t, sweep);
title('扫频信号');
xlabel('Time (s)');
ylabel('Amplitude');
subplot(312);
plot(t, spreadSignal);
title('扩频信号');
xlabel('Time (s)');
ylabel('Amplitude');
subplot(313);
plot(t, noisySignal);
title('扫频扩频调制信号');
xlabel('Time (s)');
ylabel('Amplitude');