Merge pull request #15 from ltcptgeneral/generate_sawtooth

add sawtooth generator function
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Ben Z 2021-12-05 20:30:35 -08:00 committed by GitHub
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src/generate_sawtooth.m Normal file
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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
% Arthur Lu: Format 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
%part before the straght vertical line
if(st < period /2)
x(i) = slope * st;
%part after the straght vertical line
else
x(i) = slope * st - amplitude;
end
end