clc;
clear;
Adc=2; %
A1=3; %F1
A2=1.5; %F2
A3=2.2;%F3
F1=50; %1(Hz)
F2=75; %2(Hz)
F3=75.5; %2(Hz)
Fs=256; %(Hz)
P1=-30; %1()
P2=90; %()
P3=60; %()
N=1024; %
%4s ; 0.25Hz ; 201，301，303
t=0:1/Fs:N/Fs; %
%
S=Adc+A1*cos(2*pi*F1*t+pi*P1/180)+A2*cos(2*pi*F2*t+pi*P2/180)+A3*cos(2*pi*F3*t+pi*P3/180);
figure;
plot(t,S);%
title('');
Y = fft(S,N); %FFT
figure;
Ayy = abs(Y); %
n = 1:N;
%plot(n,Ayy);
stem(Ayy(1:N)); %FFT
title('FFT ');
Ayy=Ayy/(N/2); %
Ayy(1)=Ayy(1)/2;
F=([1:N]-1)*Fs/N; %，Fn=(n-1)*Fs/N
figure;
plot(F,Ayy);
%stem(Ayy(1:N/2)); %FFT
title('-');
Pyy=[1:N/2];
for i=1:N/2
Pyy(i)=angle(Y(i)); %
Pyy(i)=Pyy(i)*180/pi; %
end;
figure;
plot(F(1:N/2),Pyy(1:N/2));
%stem(F(1:N/2),Pyy(1:N/2)); %
title('-');