implemented generate_keyboard, lfo_square

src/NotWorking/generate_keyboard.m

@@ -1,49 +0,0 @@
-function x = generate_keyboard(amplitude, frequency, phase, fs, duration, duty)
-% GENERATE_KEYBOARD: returns a matrix of a sum of sine waves
-
-% CONTRIBUTORS:
-% Ryan Goh: author
-
-% DOCUMENTATION:
-% fs is the sampling frequency: how many sample points per second
-% duration is time in seconds
-% amplitude, phase, and duty are not used in this function
-
-% This function's purpose is to generate a wave that can simulate the sound of a digital keyboard.
-% Sound is best suited for frequencies near the middle octave of the
-% piano(261.6 - 523.2). Frequencies too high or too low do not sound
-% similar to the intended sound.
-
-% Referenced Arthur Lu and Benjamin Liou's generate sine function. Also
-% adapted wave model from https://dsp.stackexchange.com/questions/46598/mathematical-equation-for-the-sound-wave-that-a-piano-makes
-
-
-    % 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
-    x = zeros(1, n);
-    
-    % populate the matrix
-    for i = 1:n
-        t = i * dt; % time at the i'th sample
-        
-        %wave model of keyboard sound. 
-        %Original version from https://dsp.stackexchange.com/questions/46598/mathematical-equation-for-the-sound-wave-that-a-piano-makes
-        y = sin(2 * pi * frequency * t) * exp(-0.002 * 2 * pi * frequency * t) ...
-        + (sin(3*2*pi*frequency*t)*exp(-0.002 * 2 * pi * frequency * t)) / 2 ...
-        + (sin(4*2*pi*frequency*t)*exp(-0.002 * 2 * pi * frequency * t)) / 8 ...
-        + (sin(5 * 2 * pi * frequency * t) * exp(-0.002 * 2 * pi * frequency * t)) / 16 ...
-        + (sin(6 * 2 * pi * frequency * t) * exp(-0.002 * 2 * pi * frequency * t)) / 25 ...
-        + (sin(7 * 2 * pi * frequency * t) * exp(-0.002 * 2 * pi * frequency * t)) / 50 ...
-        + (sin(8 * 2 * pi * frequency * t) * exp(-0.002 * 2 * pi * frequency * t)) / 100 ...
-        + (sin(9 * 2 * pi * frequency * t) * exp(-0.002 * 2 * pi * frequency * t)) / 200;
-        
-        %Further adjustments to improve sound
-        y = y + y * y * y;
-        y = y * (1 + 16*t*exp(-1000*t));
-        
-        x(i) = 0.15 * y;%multiplied by fixed amplitude value of 0.15
-    end
-end

src/NotWorking/lfo_square.m

@@ -1,37 +0,0 @@
-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