ref: f11d78d75e25f0dc4d70e437613062b597a127d5
dir: /src/temporal/c_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 _CDESIGN_H
#define _CDESIGN_H
/** \file
Create a C-weighting filter
This file creates a C-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] = cdsign(1/Fs) </pre> for various
sampling frequencies.
*/
#ifdef __cplusplus
extern "C" {
#endif
/** create new C-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_c_weighting (uint_t samplerate, uint_t channels);
/** set feedback and feedforward coefficients of a C-weighting filter
\param f filter object to get coefficients from
*/
void aubio_filter_set_c_weighting (aubio_filter_t *f);
#ifdef __cplusplus
}
#endif
#endif /* _CDESIGN_H */