www.gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\usasi.m
function x=usasi(n,fs) %USASI generates N samples of USASI noise at sample frequency FS X=(N,FS) % This is based on hearsay: I haven't read the actual standard: EIA-549-1988 % It may also be defined in ANSI standard S1.4-1961: General Purpose Sound Meter % USASI = USA Standards Institute (now ANSI) % This generates gaussian noise and filters is with zeros at 0Hz & fs/2 and poles at 100 and 320 Hz % I need to get the scaling correct % Copyright (C) Mike Brookes 1997 % % Last modified Wed Nov 22 11:42:57 2000 % % VOICEBOX is a MATLAB toolbox for speech processing. Home page is at % http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % This program is free software; you can redistribute it and/or modify % it under the terms of the GNU General Public License as published by % the Free Software Foundation; either version 2 of the License, or % (at your option) any later version. % % This program is distributed in the hope that it will be useful, % but WITHOUT ANY WARRANTY; without even the implied warranty of % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the % GNU General Public License for more details. % % You can obtain a copy of the GNU General Public License from % ftp://prep.ai.mit.edu/pub/gnu/COPYING-2.0 or by writing to % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if nargin<2 fs=8000; end b=[1 0 -1]; a=poly(exp(-[100 320]*2*pi/fs)); x=randfilt(b,a,n);