adding files for windowing

applyTemporalwindow.m

@@ -0,0 +1,20 @@
+function signal_windowed = applyTemporalwindow(signal,t,win)
+%{
+function signal_windowed = applyTemporalWindow(signal,t,win)
+Ex: i_rect = applyTemporalWindow(x,t,rect)
+
+Task: to apply (to do the multiplication) the windowing on the signal
+
+Inputs:
+    -signal: the signal we want to aplly windowing to
+    -t: time vector (in s)
+    -win: type of window 
+Output:
+    amplitude of signal_windowed 
+Author: tikea TE
+Date: 13/04/2025
+%}
+
+for I_sample = 1:length(t)
+    signal_windowed(I_sample) = signal(I_sample) * win(I_sample);
+end

createtemporalWindow.m

@@ -0,0 +1,47 @@
+function win = createTemporalWindow(t, duration_signal, duration_win, sampling_freq, win_type)
+
+%{
+fuction win = createTemporalWindow(t, duration_signal, duration_win, sampling_freq, win_type)
+Ex: win = createTemporalWindow(t, 6, 2, 40, 1)
+
+Task: create the 4 types of windowing functions
+
+Inputs:
+    -t: time vector of the signal
+    -duration_signal: duration of the signal (in s)
+    -duration_win: duration of the window
+    -sampling_freq: how many samples per second
+    -win_type: 1 for rectangle, 2 for hamming, 3 for hanning, 4 for blackman
+    
+Output:
+     win : window amplitude with the same duraion as the temporal vector
+Author: Tikea TE
+Date: 13/04/2025
+%}
+
+% create a vector of 0 the same length as the signal
+win = zeros(1,length(t));
+
+for I_sample = 1:duration_win * sampling_freq % nuber of samples in the window 
+    % for rectangle
+    if (win_type == 1)
+        win(I_sample + (duration_signal - duration_win)/2 * sampling_freq ) = 1;
+    end
+    % for hanning 
+    if (win_type == 2)
+        win(I_sample + (duration_signal - duration_win)/2 * sampling_freq ) = 0.5 - 0.5*cos(2*pi*I_sample/(duration_win*sampling_freq));
+    end
+    % for hamming
+    if (win_type == 3)
+        win(I_sample + (duration_signal - duration_win)/2 * sampling_freq ) = 0.54 - 0.46*cos(2*pi*I_sample/(duration_win*sampling_freq));
+    end
+    % for blackman
+    if (win_type == 4)
+        win(I_sample + (duration_signal - duration_win)/2 * sampling_freq ) = 0.42 - 0.5*cos(2*pi*I_sample/(duration_win*sampling_freq)) + 0.08*cos(4*pi*I_sample/(duration_win*sampling_freq));
+    end
+end
+
+
+
+
+

main.m

@@ -28,8 +28,33 @@ plotRawSignal(X, Fs);
 % ======== Apply FirFilter ===============
 filteredSignal = firFilter(30, [5 20], X, 200);  % for a 30th-order bandpass FIR filter
 
+% ============ plot the filtered signal ============
 plotFilteredSignal(filteredSignal, Fs);
 plotRawVsFiltered(X, filteredSignal, Fs);
 
+% ==== Power spectrum of the filtered signal ====
+[f_filtered, power_filtered] = frequencySpectrum(filteredSignal, Fs, 1);
+
+% === Create time vector for windowing ===
+t = (0:length(filteredSignal)-1) / Fs;
+
+% === Choose window duration ===
+duration_signal = length(filteredSignal) / Fs;
+win_duration = 2;  % seconds
+
+% === Create and apply Hanning window ===
+win_hanning = createTemporalWindow(t, duration_signal, win_duration, Fs, 2);
+x_hanning = applyTemporalwindow(filteredSignal, t, win_hanning);
+
+% === Plot raw vs windowed ===
+figure;
+plot(t, filteredSignal, 'r'); hold on;
+plot(t, x_hanning, 'b');
+legend('Filtered signal', 'Hanning-windowed');
+xlabel('Time (s)');
+ylabel('Amplitude');
+title('Windowing Effect on Filtered Signal');
+grid on;
+
 
 end

sampling.m

@@ -0,0 +1,48 @@
+function [t,x] = sampling(freq_signal, sampling_freq, phase_signal, duration, plt)
+
+%{
+function [t,x] = sampling(freq_signal, sampling_freq, phase_signal, duration, plt)
+ex: [t,x] = sampling(10,30,1,1)
+
+Task: generate a cosine function knowing frequency, sampling freq, phase and duration
+
+Inputs:
+    -freq_signal: frequency of the signal (in hz)
+    -sampling_freq: sampling frequency (how many sample per second) (in hz)
+    -phase_signal: signal phase (in rad)
+    -duration: how long u want the signal to be
+    plt: if greater than 0, signal will be plotted 
+
+Outputs:
+    -t: time vector
+    -x: amplitude of the cosine signal
+    -a figure of a cosine signal
+
+Author: Tikea TE 
+Date: 11/04/2025
+%}
+
+% generate the time vector
+t = -duration/2: 1/sampling_freq: duration/2;
+
+% generate the cosine signal
+x = cos(2*pi*freq_signal*t + phase_signal);
+
+% plotting the figure 
+if(plt)
+    figure;
+    plot(t,x,'b');
+    xlabel('Time(s)');
+    ylabel('signal amplitude(a.u.)');
+    title(['cosine signal at ', num2str(freq_signal), 'Hz']); % use [] for joining string 
+    grid on;
+end
+
+
+
+
+
+
+
+
+

windowing.m

@@ -0,0 +1,111 @@
+function windowing(freq_signal, sampling_freq, phase_signal,win_duration, duration_signal, plt)
+%{
+fuction windowing(freq_signal, sampling_freq, phase_signal,win_duration, duration_signal, plt)
+Ex: windowing(10, 40, 0, 2, 6, 1)
+
+Task: to apply the time window of the signal x (any signal)  
+
+Inputs:
+    -win_sig: duration of the window
+    -freq_signal: frequency of the signal (in hz)
+    -sampling_freq: sampling frequency (how many sample per second) (in hz)
+    -phase_signal: signal phase (in rad)
+    -duration: how long u want the signal to be
+    -plt: if greater than 0, signal will be plotted 
+    
+Output:
+     none
+
+%}
+
+[t,x] = sampling(freq_signal, sampling_freq, phase_signal, duration_signal, 0);
+
+% create the rectangle window:
+rect = createtemporalWindow(t, duration_signal, win_duration, sampling_freq, 1);
+
+% apply the rectangle window
+I_rect = applyTemporalwindow(x,t,rect);
+
+% plot the rectangular window
+if (plt)
+	figure;
+	plot(t, x, 'r'); hold on;
+	plot(t, I_rect, 'b');
+	xlabel('Time (s)');
+	ylabel('Signal amplitude (n.u.)');
+	legend('original', 'windowed');
+end
+
+% create the Hanning window:
+Hanning = createtemporalWindow(t, duration_signal, win_duration, sampling_freq, 2);
+
+% apply the hanning window
+I_hanning = applyTemporalwindow(x,t,Hanning);
+
+% plot the hanning window
+if (plt)
+    plot(t,I_hanning,'g');
+	legend('original', 'rect','hanning');
+end
+
+% create the Hamming window:
+Hamming = createtemporalWindow(t, duration_signal, win_duration, sampling_freq, 3);
+
+% apply the hamming window
+I_hamming = applyTemporalwindow(x,t,Hamming);
+
+% plot the hamming window
+if (plt)
+    plot(t,I_hamming,'k');
+	legend('original', 'rect','hanning','hamming');
+end
+
+% create the blackman window:
+blackman = createtemporalWindow(t, duration_signal, win_duration, sampling_freq, 4);
+
+% apply the blackman window
+I_blackman = applyTemporalwindow(x,t,blackman);
+
+% plot the rectangular window
+if (plt)
+    plot(t,I_blackman,'c');
+	legend('original', 'rect','hanning','hamming','blackman');
+end
+
+% compute power for each window 
+[f_rect, P_rect] = frequencySpectrum(I_rect,sampling_freq,0);
+[f_hanning, P_hanning] = frequencySpectrum(I_hanning,sampling_freq,0);
+[f_hamming, P_hamming] = frequencySpectrum(I_hamming,sampling_freq,0);
+[f_blackman, P_blackman] = frequencySpectrum(I_blackman,sampling_freq,0);
+
+% plotting
+if(plt)
+    figure;
+    % find max value and its index of DFT
+    [val, ind] = max(P_rect);
+    plot(f_rect,10*log10(P_rect/P_rect(ind)),'b');
+    hold on;
+
+    % find max value and its index of DFT
+    [val, ind] = max(P_hanning);
+    plot(f_hanning,10*log10(P_hanning/P_hanning(ind)),'r');
+    hold on;
+
+    % find max value and its index of DFT
+    [val, ind] = max(P_hamming);
+    plot(f_hamming,10*log10(P_hamming/P_hamming(ind)),'k');
+    hold on;
+
+    % find max value and its index of DFT
+    [val, ind] = max(P_blackman);
+    plot(f_blackman,10*log10(P_blackman/P_blackman(ind)),'g');
+    hold on;
+
+    xlabel('frequency (hz)');
+    ylabel('Power (dB)');
+    legend('rect','hanning','hamming','blackman');
+    xlim([0 sampling_freq]);
+
+
+end
+