gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\rfft.m
function y=rfft(x,n) %RFFT FFT of real data Y=(X,N) % Data is truncated/padded to length N if specified. % N even: (N+2)/2 points are returned with % the first and last being real % N odd: (N+1)/2 points are returned with the % first being real % Copyright (C) Mike Brookes 1998 % % Last modified Fri Apr 3 14:57:19 1998 % % VOICEBOX 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 % 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 y=fft(x); else y=fft(x,n); end if size(y,1)==1 m=length(y); y(floor((m+4)/2):m)=[]; else m=size(y,1); y(floor((m+4)/2):m,:)=[]; end