problem in plotting fft for set of samples

Hello,

i am trying to plot FFT samples vs freq.. bt not getting the exact peak at expected frequency.

i have attached the samples in excel sheet,..plz can some one help me and guide me to get peaks at expected frequency.

clear
 N=3584;
 n=0:3584
ts=.0002;
fs=1/ts
ts1=0.02
 f=1/(N*ts);
 t=[0:N-1]*ts;
 g=input('enter the frequency required')
ref=3*sin(2*pi()*g*t)
figure
plot(t,ref),axis tight
fref=abs(fft(ref))
figure
plot(abs(fref))
axis tight
 x=xlsread('41hz.xlsx')
figure
 plot(x),grid on
 axis tight
 Xf=abs(fft(x));
  f1=[0:N-1]*f
plot(f1,abs(Xf)),grid on
axis tight
n_2=ceil(N/2)
figure
plot(f1(1:n_2),abs(Xf(1:n_2))),grid on

[madhan ravi]

What value are you inputting for g?

[Sunil Kumar]

50 hz

Answer 1

[Sulaymon Eshkabilov]

Here is the corrected code that computes fft and plots accordingly.

N=3584; g=50;
ts=.0002;
fs=1/ts;
t=[0:N-1]*ts;
 L = numel(t);         % Length of your signal
 f = fs*(0:(L/2))/L;   % Frequency values
ref=3*sin(2*pi()*g*t);
figure
plot(t,ref),axis tight, title('Time domain signal')
fref=abs(fft(ref));    
figure
plot(f, abs(fref(1:N/2+1))); % plot f vs. spectrum magnitude
xlim([0, 100]) 
%% Working with your measured/sampled data
DATA = xlsread('DATA_ES.xlsx', 'Sheet2');
L = numel(DATA(:, 1));   % Length of the signal
figure
ts=.0002; fs=1/ts;
Xf=abs(fft(DATA(:,1)));  % Assuming Column 1 contains frequency response data
f=fs*(0:(L/2))/L;
n_2=ceil(N/2);
plot(f,abs(Xf(1:n_2+1))),grid on

[Sunil Kumar]

Thank you so much

[Sulaymon Eshkabilov]

You are most welcome!