MATLAB Answers

How to plot the fft if we are having the data ?

2 views (last 30 days)
vimal kumar chawda
vimal kumar chawda on 9 Jul 2021
load('Lp_400_Bw5.mat')
xlsread('Messdaten');
time=ans(:,1); % Time vector
data = ans(:,2);
Messdaten1=ans(:,2);
fs=1/1.000000000000000e-03;
N=size(Messdaten1);
% X=fft({Messdaten}*2/N;
%f=fs/(N)*(1:N)
hfp = fplot(Messdaten1);
xv = hfp.XData;
yv = hfp.YData;
X=fft(yv);
Error is Error using fft
Invalid data type. First argument must be double, single, int8, uint8, int16, uint16, int32, uint32, or
logical.

Answers (1)

Sulaymon Eshkabilov
Sulaymon Eshkabilov on 10 Jul 2021
Hi,
Here is a correct and complete code for fft calc and plot with your data given in .xls data file:
clearvars; clf;
D=readtable('Messdaten.xls');
time=D.Var1; % Time
X = D.Var2; % Data
Fs=1e3; % Sampling frequency, [Hz]
L = length(X);
N = 2^nextpow2(L);
Y = fft(X, N);
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;
plot(f,P1)
title('Single-Sided Amplitude Spectrum of S(t)')
xlabel('f (Hz)')
ylabel('|P1(f)|')

Community Treasure Hunt

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

Start Hunting!