% Test de la fonction FFT

clear all; close all; clc;
global Window_Size

% Definition of the parameters for the Frequency analysis
Method = 'Hamming'; % Selection of windowing: 'Hamming'  /  'Hann'  /  'Rectangle'
fs = 2000; % Hz Sampling frequency
Overlap = 0.5; % 50% of overlap
Window_Size = 2^13; % Attention, on ne peut pas mettre n'importe quelle valeur ! Cela dépend de la fréquence d'échantillonage, de la longueur du signal, ...

% Definition of a sinus for a test
f = 200.1; % Frequency Careful : choose a frequency corresponding to one multiple of the frequency resolution ! 
A = 2; % Amplitude
Time = [0:1/fs:20];
Signal = A*sin(2*pi*f*Time);

% Application of the Sxx function
[Frequency, Sxx] = Sxx_Function_Local(Time, Signal, Method, Overlap, Window_Size);

% Display
figure(1)
subplot(2,1,1)
plot(Time, Signal)
xlim([0 max(Time)])

subplot(2,1,2)
plot(Frequency, (Sxx))
xlim([0 500])

% Computation of the maximum amplitude
[Max_Value, Idx] = max(sqrt(Sxx));
fprintf('The maximum amplitude of the signal is equal to : %.2f\n', Max_Value)