45 lines
1.4 KiB
Matlab
45 lines
1.4 KiB
Matlab
function x = generate_halfCircles(amplitude, frequency, phase, fs, duration, duty)
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% Generates half circles.
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% By Conner Hsu
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% DOCUMENTATION:
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% amplitude scales how tall the half circle is.
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% phase shift is in number of periods
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% fs is the sampling frequency: how many sample points per second
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% duration is time in seconds
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% duty cycle should be a number between 0 and 1.
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% duty of 0 or less would return 0 for all sample points
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% duty of 0.25 would return a half circle for first quarter of each cycle
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% then return 0 for the remaining 3/4ths
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% duty of 1 would return all +amplitude
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% initialize local variables from input arguments
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n = fs * duration; % number of samples (length of matrix)
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dt = 1 / fs; % sampling period: time between two sample points
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% initialize a one dimensional zero matrix to be populated
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x = zeros(1, n);
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% populate the matrix
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for i = 1:n
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t = i * dt; % time at the i'th sample
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% periodic ramp from 0 to 1
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% progression through a cycle
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st = mod(frequency * t - phase, 1);
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if(st < duty)
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x(i) = sqrt((duty/2)^2-(st-duty/2)^2)/2*amplitude;
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else
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x(i) = 0;
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end
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end
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%Testing code.
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%t = 0:dt:duration;
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%t(n) = [];
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%plot(t, x);
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sound(x, fs);
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end
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