additional comments for :

generate_sine,
generate_square,
generate_triangle,
from Benjamin Liou

src/generate_sine.m

@@ -1,15 +1,28 @@
 function x = generate_sine(amplitude, frequency, phase, fs, duration, duty)
-%GENERATE_SINE:Arthur Lu returns a matrix of sampled sine wave, where the
-%phase shift is in number of periods
-    x = zeros(1, fs * duration);
-    A = amplitude;
-    f = frequency;
-    p = phase;
-    n = fs * duration;
-    dt = 1 / fs;
+% 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;
-        x(i) = A * sin(2 * pi * f * t - p);
+        t = i * dt; % time at the i'th sample
+        x(i) = amplitude * sin(2 * pi * frequency * t - phase);
     end
 end