gusucode.com > 《MATLAB图像与视频处理实用案例详解》代码 > 《MATLAB图像与视频处理实用案例详解》代码/第 19 章 基于语音识别的信号灯图像模拟控制技术/voicebox/usasi.m
function x=usasi(n,fs) %USASI generates N samples of USASI noise at sample frequency FS X=(N,FS) % This routine is based on the USASI noise defined in [1] which was later % reissued as [2]. USASI noise is intended to simulate the long-term average % of typical audio program material. The routine does not currently implement % the pulsation at 2.5Hz 12.5% duty cycle that is recommended by the standard. % Also it should probably be scaled to a well-defined power. % % [1] NRSC AM Reemphasis, Deemphasize, and Broadcast Audio Transmission Bandwidth Specifications, % EIA-549 Standard, Electronics Industries Association , July 1988. % [2] NRSC AM Reemphasis, Deemphasize, and Broadcast Audio Transmission Bandwidth Specifications, % NRSC-1-A Standard, Sept 2007, Online: http://www.nrscstandards.org/SG/NRSC-1-A.pdf % Copyright (C) Mike Brookes 1997 % Version: $Id: usasi.m,v 1.6 2008/05/27 08:38:05 dmb Exp $ % % VOICEBOX is a MATLAB toolbox for speech processing. % Home page: 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 % http://www.gnu.org/copyleft/gpl.html 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);