Problem using fft();

2 views (last 30 days)
atharva aalok
atharva aalok on 21 Oct 2021
Commented: atharva aalok on 21 Oct 2021
I have a periodic signal with TimePeriod~2.3 that is f~.4347
But I am getting another peak at f = 0.
load('myData.mat');
figure(1);
plot(tSol, omegaSol);
% This is periodic with TimePeriod~2.3 or f~.4347
Fs = length(tSol) / (max(tSol)-min(tSol)); % Sampling frequency
T = 1/Fs; % Sampling period
L = Fs * (max(tSol) - min(tSol)); % Length of signal
t = (0:L-1)*T; % Time vector
Y = fft(omegaSol);
P2 = abs(Y/L);
P1 = P2(1:L/2+1);
P1(2:end-1) = 2*P1(2:end-1);
f = Fs*(0:(L/2))/L;
limit_f = f < 1;
f = f(limit_f);
P1 = P1(limit_f);
figure(2);
plot(f,P1)
title('Single-Sided Amplitude Spectrum of X(t)')
xlabel('f (Hz)')
ylabel('|P1(f)|')
Why Is there another peak at f ~ 0?

Accepted Answer

KSSV
KSSV on 21 Oct 2021
Edited: KSSV on 21 Oct 2021
Remove the mean from the data and then use fft.
Say A is your data, (array). For fft use:
A = A-mean(A) ;
  1 Comment
atharva aalok
atharva aalok on 21 Oct 2021
Yeah lol I just realised a second after posting thanks!

Sign in to comment.

More Answers (0)

Categories

Find more on Fourier Analysis and Filtering in Help Center and File Exchange

Products


Release

R2021a

Community Treasure Hunt

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

Start Hunting!