4ask调制与解调的matlab
时间: 2023-10-24 09:04:56 浏览: 95
在MATLAB中进行4ASK调制和解调可以使用以下代码:
1. 4ASK调制
```matlab
% 设置调制参数
fc = 100; % 载波频率
fbit = 10; % 比特率
tb = 1/fbit; % 每个比特的时间
A = 1; % 振幅
% 生成二进制比特流
bits = [1 0 1 1 0 1 0 0];
% 调制
t = 0:tb/100:tb-tb/100;
carrier = A*sin(2*pi*fc*t);
signal = [];
for i=1:length(bits)
if bits(i) == 1
signal = [signal A*sin(2*pi*fc*t)];
else
signal = [signal -A*sin(2*pi*fc*t)];
end
end
% 绘制调制后的信号波形
t = 0:tb/100:length(bits)*tb-tb/100;
figure;
subplot(3,1,1);
plot(t, signal);
title('4ASK调制信号');
xlabel('时间(s)');
ylabel('幅度(V)');
grid on;
subplot(3,1,2);
plot(t, carrier);
title('载波信号');
xlabel('时间(s)');
ylabel('幅度(V)');
grid on;
subplot(3,1,3);
plot(t, signal+carrier);
title('调制后的信号');
xlabel('时间(s)');
ylabel('幅度(V)');
grid on;
```
2. 4ASK解调
```matlab
% 设置调制参数
fc = 100; % 载波频率
fbit = 10; % 比特率
tb = 1/fbit; % 每个比特的时间
A = 1; % 振幅
% 生成二进制比特流
bits = [1 0 1 1 0 1 0 0];
% 调制
t = 0:tb/100:tb-tb/100;
carrier = A*sin(2*pi*fc*t);
signal = [];
for i=1:length(bits)
if bits(i) == 1
signal = [signal A*sin(2*pi*fc*t)];
else
signal = [signal -A*sin(2*pi*fc*t)];
end
end
% 添加高斯白噪声
noise = 0.1*randn(1,length(signal));
signal = signal + noise;
% 解调
demod_signal = [];
for i=1:length(bits)
t = (i-1)*tb:tb/100:i*tb-tb/100;
x = signal(t >= (i-1)*tb & t < i*tb);
if sum(x >= 0) > sum(x < 0)
demod_signal = [demod_signal 1];
else
demod_signal = [demod_signal 0];
end
end
% 绘制解调后的信号波形
t = 0:tb/100:length(bits)*tb-tb/100;
figure;
subplot(3,1,1);
plot(t, signal);
title('接收到的信号');
xlabel('时间(s)');
ylabel('幅度(V)');
grid on;
subplot(3,1,2);
plot(t, carrier);
title('载波信号');
xlabel('时间(s)');
ylabel('幅度(V)');
grid on;
subplot(3,1,3);
stairs(t, demod_signal);
title('解调后的信号');
xlabel('时间(s)');
ylabel('二进制比特');
grid on;
```
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