ref: ae6e15c80aa3700300828afe172fd5fad3b9cdc5
dir: /src/temporal/a_weighting.h/
/* Copyright (C) 2003-2009 Paul Brossier <piem@aubio.org> This file is part of aubio. aubio 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 3 of the License, or (at your option) any later version. aubio 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 should have received a copy of the GNU General Public License along with aubio. If not, see <http://www.gnu.org/licenses/>. */ #ifndef _ADESIGN_H #define _ADESIGN_H /** \file Create an A-weighting filter This file creates an A-weighting digital filter, which reduces low and high frequencies and enhance the middle ones to reflect the ability of the human hearing. The implementation is based on the following standard: - IEC/CD 1672: Electroacoustics-Sound Level Meters, IEC, Geneva, Nov. 1996, for A- and C-weighting filters. See also: - <a href="http://en.wikipedia.org/wiki/A-weighting">A-Weighting on Wikipedia</a> - <a href="http://en.wikipedia.org/wiki/Weighting_filter">Weighting filter on Wikipedia</a> - <a href="http://www.mathworks.com/matlabcentral/fileexchange/69">Christophe Couvreur's 'octave' toolbox</a> The coefficients in this file have been computed using Christophe Couvreur's scripts in octave 3.0 (debian package 1:3.0.5-6+b2 with octave-signal 1.0.9-1+b1 on i386), with <pre> [b, a] = adsign(1/Fs) </pre> for various sampling frequencies. */ #ifdef __cplusplus extern "C" { #endif /** create new A-design filter \param samplerate sampling frequency of the signal to filter. Should be one of 8000, 16000, 22050, 44100, 96000, 192000. \param channels number of channels to allocate \return a new filter object */ aubio_filter_t * new_aubio_filter_a_weighting (uint_t samplerate, uint_t channels); /** set feedback and feedforward coefficients of a A-weighting filter \param f filter object to get coefficients from */ void aubio_filter_set_a_weighting (aubio_filter_t *f); #ifdef __cplusplus } #endif #endif /* _ADESIGN_H */