正弦波 / Sinewave

function out = synth_sinewave(freq, ms, fs)
%SYNTH_SINEWAVE   Sine wave generator.
%   synth_sinewave(freq, ms, fs) generates a sinusoidal wave of
%   specified pitch and duration with unity amplitude.
%
%   freq - frequency of the tone in Hertz
%     ms - duration in milli-second
%     fs - sampling frequency in Hertz
%
%   2002-10-30 by MARUI Atsushi

out = zeros(ceil(fs*ms/1000), 1);

c = 2 * pi * (freq / fs);
i=[1:size(out, 1)];
out(i) = sin(c * (i-1));
out = normalize(out);