clc;
clear;
close all;
warning off;
f=1000; %载波频率
fs=100000; %采样频率
N=5000; %采样点
Ts=1/fs; %采样周期
t=(0:Ts:(N*Ts)- Ts);
f1=200; %调制频率
msg=sin(2*pi*f1*t)+0.5*cos(7*pi*f1*t); %模拟发送信号sin,这里可以变更你的发送信号！
%msg = 0.5*square(2*pi*f1*t);
%msg=sin(4*pi*f1*t)
kf=0.0628; %调制常数
Signal=exp(j*(2*pi*f*t+2*pi*kf*cumsum(msg))); %调制载波
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%产生PLL
phi(1)=30; %锁相环的初始化
error(1)=0; %锁相环的初始化
phd(1)=0; %锁相环的初始化
vco(1)=0; %锁相环的初始化
kp=0.15;
ki=0.1;
%PLL 频率跟踪过程
for n=2:length(Signal)
vco(n)=conj(exp(j*(2*pi*n*f/fs+phi(n-1))));
phd(n)=imag(Signal(n)*vco(n));
error(n)=error(n-1)+(kp+ki)*phd(n)-ki*phd(n-1);
phi(n)=phi(n-1)+error(n);
end;
start_point = 1;
end_point = 3000;
figure(1);
subplot(2,1,1);
plot(msg(start_point:end_point));
axis([start_point,end_point,-1.5,1.5]);
title('100 Hz信号');
grid;
subplot(2,1,2);
plot(real(Signal(start_point:end_point)));
axis([start_point,end_point,-1.5,1.5]);
title('FM (利用1KHZ的载波对信号进行调制)');
grid;
figure(2);
subplot(3,1,1);
plot(error(start_point:end_point));
axis([start_point,end_point,-1.5,1.5]);
title('PLL输出');
grid;
subplot(3,1,2);
plot(real(vco(start_point:end_point)));
axis([start_point,end_point,-1.5,1.5]);
title('频率锁定以后的信号输出');
grid;
subplot(3,1,3);
plot(phd(start_point:end_point));
axis([start_point,end_point,-1.5,1.5]);
title('PLL相位输出');
grid;
