%%%%%%%%%%%%%%%%
%
%Author: Gabriel LUCAS
%
%Creation: 20/04/23 10:08
%
%Last Modified: 20/04/23 10:08
%
%%%%%%%%%%%%%%%%
pkg load signal;

samplingFreq = 300; %Hz

fMin = 30; %Hz
fMax = 40; %Hz

signal = csvread('unknownsignal.csv');

signalDuration = size(signal,2)/samplingFreq; %s
t=[0:1/samplingFreq:(size(signal,2)-1)/samplingFreq];
windowDuration = signalDuration/2;

figure;
plot(t,signal)
xlabel('Time (s)');
ylabel('Sound (dB)');
title('unknown Signal');

blackmanWin = zeros(1, length(t));
for l_sample=1:windowDuration*samplingFreq
	blackmanWin(l_sample+signalDuration*samplingFreq/4) = (0.42 - 0.5 * cos(2*pi*(l_sample)/(signalDuration*samplingFreq/2)) + 0/08*cos(4*pi*(l_sample)/(windowDuration*samplingFreq/2)));
end

% plot Blackman window
%~ figure;
%~ plot(t, blackmanWin);

% apply the Blackman window
for l_sample=1:length(t)
	signal_blackman(l_sample) = signal(l_sample) * blackmanWin(l_sample);
end

% plot signal windowed by rectangular window
%~ figure;
%~ plot(t, signal_blackman);

% plot the frequency spectrum of this windowed signal
power_blackman = frequencySpectrum(signal_blackman, samplingFreq);


fft_signal = fft(signal);
size(fft_signal)

figure;
plot(t, fft_signal);
xlabel('Freq (Hz)');
ylabel('Sound (dB)');
title('FFT of signal');


N=size(signal)(2);
freq=(0:N-1)*samplingFreq/N;
%frequency from frame rate


minfreq=30; %Hz
maxfreq=40; %Hz
idx_min = find(freq >= minfreq, 1);
idx_max = find(freq <= maxfreq, 1, 'last');
filtered_freq = freq(idx_min:idx_max);
figure;
plot(t, filtered_freq);



%[a, b] = butter(1, [1/fMax, 1/fMin], 'bandpass');
%filtered_signal = filter(b,1, signal);
%figure;
%plot(t,filtered_signal)
%xlabel('Time (s)');
%ylabel('Sound (dB)');