调制与解调MATLAB

virtual1985

PM
Fs=100;
Fc=10;
t=[0:200]/Fs;
x=sin(2*pi*t);
kp = pi/max(max(abs(x)));
y = cos(2*pi*Fc*t + kp*x);
yq = hilbert(y).*exp(-j*2*pi*Fc*t);
x1=unwrap(angle(yq));
subplot(3,1,1);
plot(x);
subplot(3,1,2);
plot(y);
subplot(3,1,3);
plot(x1);
FM
Fs=100;
Fc=10;
t=[0:200]/Fs;
x=sin(2*pi*t);
kf = (Fc/Fs)*2*pi/max(max(abs(x)));
y = cos(2*pi*Fc*t + kf*cumsum(x));
yq = hilbert(y).*exp(-j*2*pi*Fc*t);
x1=diff(unwrap(angle(yq)));
[b,a]=butter(3,Fc*2/Fs);
x2= filtfilt(b,a,x1);
subplot(3,1,1);
plot(x);
subplot(3,1,2);
plot(y);
subplot(3,1,3);
plot(x2);
am dsb
Fs=100;
Fc=10;
t=[0:200]/Fs;
x=sin(2*pi*t);
y = x.*cos(2*pi*Fc*t);
x1= y.*cos(2*pi*Fc*t);
[b,a]=butter(5,Fc*2/Fs);
x2 = filtfilt(b,a,x1);
subplot(3,1,1);
plot(x);
subplot(3,1,2);
plot(y);
subplot(3,1,3);
plot(x2);

ssb
Fs=100;
Fc=10;
t=[0:200]/Fs;
x=sin(2*pi*t);
y = x.*cos(2*pi*Fc*t) + imag(hilbert(x)).*sin(2*pi*Fc*t);
x1= y.*cos(2*pi*Fc*t);
[b,a]=butter(5,Fc*2/Fs);
x2 = filtfilt(b,a,x1);
subplot(3,1,1);
plot(x);
subplot(3,1,2);
plot(y);
subplot(3,1,3);
plot(x2);