白色雑音 / Whitenoise

function out = synth_whitenoise(ms, fs)
%SYNTH_WHITENOISE   Whitenoise Generator
%   synth_whitenoise(ms, fs) generates a Gaussian whitenoise of
%   specified duration with unity amplitude at the maximum peak.
%
%   ms - duration of noise in milli-seconds
%   fs - sampling frequency in Hz
%
%   2003-01-03 by MARUI Atsushi
%   2003-02-04 Fixed a bug so that it generates noise in proper range.
%   2004-09-15 Fixed to use randn instead of rand
%              (now a valid Gaussian white noise)

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