スウィープ / Sweeped Sinewave

function y = synth_sinesweep(ms, fs)
%SYNTH_SINESWEEP   generate sinusoidal sweep (chirp) signal
%   synth_sinesweep(ms, fs) generates a sweeping sinusoidal wave from
%   DC to Nyquist of specified duration with unity amplitude.
%
%   Input:
%      ms - duration in milli-second
%      fs - sampling frequency in Hertz
%
%   Example:
%      y = synth_sinesweep(1000, 44100);
%      sound(y, 44100);
%      specgram(y, 256, 44100);
%
%   2004-11-11 by MARUI Atsushi

method = 'logarithmic';

t = 0 : 1/fs : ms/1000;
t = t(1:length(t)-1);
y = chirp(t, min(t), max(t), fs/2, method);