How can I plot 'period' by using fft functoin??

3 vues (au cours des 30 derniers jours)
Chris
Chris le 7 Nov 2021
Commenté : Mathieu NOE le 8 Nov 2021
How can I plot 'period' by using fft functoin??
  1 commentaire
Mathieu NOE
Mathieu NOE le 8 Nov 2021
hello
maybe you should show what you have tried so far... and then we will help you
tx

Connectez-vous pour commenter.

Réponse acceptée

Chunru
Chunru le 8 Nov 2021
Fs = 1000; % Sampling frequency
T = 1/Fs; % Sampling period
L = 1500; % Length of signal
t = (0:L-1)*T; % Time vector
S = 0.7*sin(2*pi*50*t) + sin(2*pi*120*t);
X = S + 2*randn(size(t));
Y = fft(X);
% Compute the two-sided spectrum P2. Then compute the single-sided spectrum P1
% based on P2 and the even-valued signal length L.
P2 = abs(Y/L);
P1 = P2(1:L/2+1);
P1(2:end-1) = 2*P1(2:end-1);
% Define the frequency domain f and plot the single-sided amplitude spectrum P1.
% The amplitudes are not exactly at 0.7 and 1, as expected, because of the added
% noise. On average, longer signals produce better frequency approximations.
figure
f = Fs*(0:(L/2))/L;
plot(f,P1)
title('Single-Sided Amplitude Spectrum of X(t)')
xlabel('f (Hz)')
ylabel('|P1(f)|')
%% Plot the spectrum vs period (this can be done but rarely used)
figure
f = Fs*(0:(L/2))/L;
plot(1./f,P1)
title('Single-Sided Amplitude Spectrum of X(t)')
xlabel('T - period (sec)')
ylabel('|P1(T)|')
xlim([0 0.2])

Plus de réponses (0)

Catégories

En savoir plus sur Fourier Analysis and Filtering dans Help Center et File Exchange

Tags

Produits

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by