Talk:Fft.R

Matlab example

Fs = 5000; % Sampling frequency [Hz]
Ts = 20; % Length of sample [s]
f = 2; % Frequency of signal [Hz]
f2 = 2.7; 
t = linspace(0,Ts,Fs*Ts); % Time series [s]
y = 1.3*sin(2*pi*f*t)+.5*sin(2*pi*f2*t+20*pi/180)+10*randn(size(t)); % the signal [V]
figure(1);
plot(t,y);
grid;
Fy = fft(y)/length(y)*2;
f = Fs/2*linspace(0,2,length(Fy));
figure(2);
subplot(2,1,1);
plot(f,abs(Fy));
grid;
xlim([1.9 2.8]);
subplot(2,1,2);
grid;
plot(f,angle(Fy)*180/pi,'.');
xlim([1.9 2.8]);
grid;

See also

• Matlab FFT example