From cb6547ad0bb664a631e8379e0f5ceb8a3b35fd37 Mon Sep 17 00:00:00 2001 From: Daniel Doan Date: Fri, 10 Dec 2021 01:50:47 -0800 Subject: [PATCH] created generate_trapezoid.m --- src/generate_trapezoid.m | 55 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 src/generate_trapezoid.m diff --git a/src/generate_trapezoid.m b/src/generate_trapezoid.m new file mode 100644 index 0000000..69ce591 --- /dev/null +++ b/src/generate_trapezoid.m @@ -0,0 +1,55 @@ +function x = generate_trapezoid(amplitude, frequency, phase, fs, duration, duty) +% GENERATE_TRAPEZOID: returns a matrix of sampled square wave + +% CONTRIBUTORS: +% Daniel Doan: 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 cycle should be a number between 0 and 1. + % duty of 0.5 would have 2 trapezoids in first half of each cycle + % example of wave with duty of 0.5, where the peaks are amplitude/2: + % + % ____ + % / \ + % / \ ________________ + % \ / + % \____/ + % + + + +% 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); + slope = (amplitude/2) / (duty/8); + if(st < duty) + if(st < duty/8 || st > 7*duty/8) + x(i) = slope * st; + else + if(st < 5*duty/8) + x(i) = amplitude/2 - slope * (st-(3*duty/8)); + end + if(st < 3*duty/8) + x(i) = amplitude/2; + end + if(st > 5*duty/8) + x(i) = -amplitude/2; + end + end + end + end +end \ No newline at end of file