moved lfo_square, generate_lullaby to NotWorking

src/NotWorking/generate_lullaby.m

@@ -0,0 +1,66 @@
+function x = generate_lullaby(amplitude, frequency, phase, fs, duration, duty)
+    % Generates sine waves that play 'twinkle twinkle little star' 
+    % by using the frequency parameter as the root note for the melody.
+    % Currently the duty and duration parameters are not used within the
+    % function as there is no need for the former and it is currently
+    % difficult to constrain the melody duration based on user input.
+    % A function such as this one could be useful as a demo for what a
+    % melody sounds like on a synthesizer, and could even find use
+    % in toys designed to help small children sleep.
+
+    % CONTRIBUTORS:
+    % generate_lullaby created by Gabriel Diaz
+
+    % DOCUMENTATION:
+    % phase shift is in number of periods
+    % fs is the sampling frequency: how many sample points per second
+    % duration is time in seconds
+    % duty is a number between 0 and 1
+
+    %NOTE: whatever's passed as the duration parameter doesn't get used at
+    %the moment, since it's currently difficult to sync every note in the
+    %melody to play in shorter duartions such that the entire song lasts about
+    %as long as 'duration'
+    duration = 0;
+    duty = 0; %duty also isn't used in this function
+
+    %current durations that the song will work with
+    note_duration = 0.4;
+    song_duration = note_duration * 48;
+
+    %frequency multiples for all notes in melody, assuming that frequency is
+    %the root note of this chord:
+    maj_second_freq = frequency * 1.125;
+    maj_third_freq = frequency * 1.25;
+    fourth_freq = frequency * 1.33;
+    fifth_freq = frequency * 1.5;
+    maj_sixth_freq = frequency * 1.7;
+
+    % initialize local variables from input arguments
+    n = fs * note_duration; % number of samples (length of matrix)
+    dt = 1 / fs; % sampling period: time between two sample points
+    t = [1:n].*dt - phase; %initialize time scale template
+
+    %sine waves for every note in 'frequency's' respective major scale: 
+    first = amplitude * sin(2 * pi * frequency * t - phase);
+    second = amplitude * sin(2 * pi * maj_second_freq * t - phase);
+    third = amplitude * sin(2 * pi * maj_third_freq * t - phase);
+    fourth = amplitude * sin(2 * pi * fourth_freq * t - phase);
+    fifth = amplitude * sin(2 * pi * fifth_freq * t - phase);
+    sixth = amplitude * sin(2 * pi * maj_sixth_freq * t - phase);
+
+    %each one of the three melodies making up the song:
+    melody1 = [first,first,fifth,fifth,sixth,sixth,fifth,fifth]; %size 8 notes
+    melody2 = [fourth,fourth,third,third,second,second,first,first]; %size 8 notes
+    melody3 = [fifth,fifth,fourth,fourth,third,third,second,second]; %size 8 notes
+
+    % populate the matrix(total size is 44 notes wide, which means the song's
+    % duration must fit within the specified duration parameter
+    x = [melody1,melody2,melody3,melody3,melody1,melody2];
+
+    %For testing
+    %t = 0:dt:song_duration;
+    %t(n) = [];
+    %plot(t, x);
+    %sound(x, fs);
+end

src/NotWorking/lfo_square

@@ -0,0 +1,37 @@
+function x = lfo_square(amplitude, frequency, phase, fs, duration, input)
+% LFO_SQUARE: modulates an input matrix to a square
+
+% CONTRIBUTORS:
+% Aleksandra Desens: Author
+
+% DOCUMENTATION:
+% phase shift is in number of periods
+% fs is the sampling frequency - below 20 Hz
+% duration - same as input
+
+    % initialize local variables from input arguments
+    n = fs * duration; % number of samples (length of matrix)
+    dt = 1 / fs; % sampling period: time between two sample points
+    
+    % initialize a one dimensional zero matrix to be populated
+    lfo = zeros(1, n);
+    
+    % populate the matrix
+    for i = 1:n
+        
+        t = i * dt;
+        duty = 0.5;  % duty of 0.5 generates a square wave
+
+        st = mod((frequency * t - phase), 1);
+
+        if (st < duty) 
+            lfo(i) = amplitude;
+        else
+            lfo(i) = -amplitude;
+
+    end
+
+    % modulate input
+    x = lfo .* input;
+
+end