Reorganized Into Folders

src/Generators/generate_halfCircles.m

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+function x = generate_halfCircles(amplitude, frequency, phase, fs, duration, duty)
+    % Generates half circles.
+
+    % By Conner Hsu
+
+    % DOCUMENTATION:
+    % amplitude scales how tall the half circle is.
+    % phase shift is in number of periods
+    % fs is the sampling frequency: how many sample points per second
+    % duration is time in seconds
+    % duty cycle should be a number between 0 and 1.
+        % duty of 0 or less would return 0 for all sample points
+        % duty of 0.25 would return a half circle for first quarter of each cycle
+        % then return 0 for the remaining 3/4ths
+    % duty of 1 would return all +amplitude
+
+    % 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
+        
+        % periodic ramp from 0 to 1
+        % progression through a cycle
+        st = mod(frequency * t - phase, 1);
+        
+        if(st < duty)
+            x(i) = sqrt((duty/2)^2-(st-duty/2)^2)/2*amplitude;
+        else
+            x(i) = 0;
+        end
+    end
+    %Testing code.
+    %t = 0:dt:duration;
+    %t(n) = [];
+    %plot(t, x);
+    sound(x, fs);
+end

src/Generators/generate_sawtooth.m

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+function x = generate_sawtooth(amplitude, frequency, phase, fs, duration, duty)
+% generate_sawtooth: returns a matrix of sampled sawtooth wave
+
+% CONTRIBUTORS:
+% Ben Zhang: Function author
+
+% 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 
+    %duty does not apply for sawtooth wave
+
+    % 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
+    period = 1 / frequency; % period of the wave
+    
+    % initialize a one dimensional zero matrix to be populated
+    x = zeros(1, n);
+    
+    
+    % populate the matrix
+    for i = 1:n
+        t = i * dt; % time of the i'th sample
+        st = mod(frequency * t - phase, 1); % Progression through cycle
+        
+        slope = 2 * amplitude / period; % the incline slope from start to amplitude
+        mid = period / 2;
+        
+        %part before the straght vertical line
+        if(st < mid)
+            x(i) = slope * st; % amplitude from start to +amplitude
+        
+        %part after the straght vertical line
+        else
+            x(i) = slope * (st - 0.5) - amplitude; %amplitude from -amplitude to start
+        
+    end
+end

src/Generators/generate_sine.m

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+function x = generate_sine(amplitude, frequency, phase, fs, duration, duty)
+% GENERATE_SINE: returns a matrix of sampled sine wave
+
+% CONTRIBUTORS:
+% Arthur Lu: Original author
+% Benjamin Liou: refactoring and annotations
+
+% 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 does not apply for sinusoids
+   
+
+    % 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
+        x(i) = amplitude * sin(2 * pi * frequency * t - phase);
+    end
+end
+

src/Generators/generate_square.m

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+function x = generate_square(amplitude, frequency, phase, fs, duration, duty)
+% GENERATE_SQUARE: returns a matrix of sampled square wave
+
+% CONTRIBUTORS:
+% Arthur Lu: Original author
+% Benjamin Liou: refactoring and annotations
+
+% 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 cycle should be a number between 0 and 1.
+    % duty of 0 or less would return -amplitude for all sample points
+    % duty of 0.25 would return +amplitude for first quarter of each cycle
+        % then return -amplitude for the remaining three-fourths
+    % duty of 1 would return all +amplitude
+
+
+% 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
+        
+        % periodic ramp from 0 to 1
+        % progression through a cycle
+        st = mod(frequency * t - phase, 1);
+        
+        if(st < duty)
+            x(i) = amplitude;
+        else
+            x(i) = -amplitude;
+        end
+    end
+end
+

src/Generators/generate_triangle.m

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+function x = generate_triangle(amplitude, frequency, phase, fs, duration, duty)
+% GENERATE_TRIANGLE: returns a matrix of sampled square wave
+
+% CONTRIBUTORS:
+% Arthur Lu: Original author
+% Benjamin Liou: refactoring and annotations
+
+% 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 cycle should be a number between 0 and 1.
+    % duty of 0.25 would have positive slope for first quarter of each cycle
+        % then have negative slope for the remaining three-fourths
+
+
+
+% 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;
+        
+        % periodic ramp from 0 to 1
+        % progression through a cycle
+        st = mod(frequency * t - phase, 1);
+        
+        if(st < duty)
+            slope = amplitude / duty;
+            intercept = -0.5 * amplitude;
+            x(i) = slope * st + intercept;
+        else
+            slope = -amplitude / (1 - duty);
+            intercept = amplitude*( duty/(1-duty) + 0.5);
+            x(i) = slope * st + intercept;
+        end
+    end
+end

src/Generators/generate_white.m

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+function x = generate_white(amplitude, fs, duration)
+%GENERATE_WHITE: returns a matrix of sampled white noise
+
+%CONTRIBUTORS:
+%Benjamin Liou: Original author
+
+%DOCUMENTATION:
+% white noise can then be filtered to produce different hues of noises
+
+
+%time domain matrix of random sample points between +-amplitude
+x = amplitude * 2 * (rand(1, fs * duration) - 0.5);
+end