ref: c19f9e573b86231d4f8bdaa7cd6b6d2b0cf7c8aa
dir: /src/temporal/biquad.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 BIQUAD_H #define BIQUAD_H /** \file Second order Infinite Impulse Response filter This file implements a normalised biquad filter (second order IIR): \f$ y[n] = b_0 x[n] + b_1 x[n-1] + b_2 x[n-2] - a_1 y[n-1] - a_2 y[n-2] \f$ The filtfilt version runs the filter twice, forward and backward, to compensate the phase shifting of the forward operation. See also <a href="http://en.wikipedia.org/wiki/Digital_biquad_filter">Digital biquad filter</a> on wikipedia. \example temporal/test-biquad.c */ #ifdef __cplusplus extern "C" { #endif /** set coefficients of a biquad filter \param f filter object as returned by new_aubio_filter() \param b0 forward filter coefficient \param b1 forward filter coefficient \param b2 forward filter coefficient \param a1 feedback filter coefficient \param a2 feedback filter coefficient */ uint_t aubio_filter_set_biquad (aubio_filter_t * f, lsmp_t b0, lsmp_t b1, lsmp_t b2, lsmp_t a1, lsmp_t a2); /** create biquad filter with `b0`, `b1`, `b2`, `a1`, `a2` coeffs \param b0 forward filter coefficient \param b1 forward filter coefficient \param b2 forward filter coefficient \param a1 feedback filter coefficient \param a2 feedback filter coefficient */ aubio_filter_t *new_aubio_filter_biquad (lsmp_t b0, lsmp_t b1, lsmp_t b2, lsmp_t a1, lsmp_t a2); #ifdef __cplusplus } #endif #endif /*BIQUAD_H*/