ref: 04ceeab0124ab3e08530e0ebbf93179c3ba7d31d
dir: /src/temporal/biquad.h/
/* Copyright (C) 2003 Paul Brossier 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 should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #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_1 x[n] + b_2 x[n-1] + b_3 x[n-2] - a_2 y[n-1] - a_3 y[n-2] \f$ The filtfilt version runs the filter twice, forward and backward, to compensate the phase shifting of the forward operation. */ #ifdef __cplusplus extern "C" { #endif /** biquad filter object */ typedef struct _aubio_biquad_t aubio_biquad_t; /** filter input vector \param b biquad object as returned by new_aubio_biquad \param in input vector to filter */ void aubio_biquad_do(aubio_biquad_t * b, fvec_t * in); /** filter input vector forward and backward \param b biquad object as returned by new_aubio_biquad \param in input vector to filter \param tmp memory space to use for computation */ void aubio_biquad_do_filtfilt(aubio_biquad_t * b, fvec_t * in, fvec_t * tmp); /** create new biquad filter \param b1 forward filter coefficient \param b2 forward filter coefficient \param b3 forward filter coefficient \param a2 feedback filter coefficient \param a3 feedback filter coefficient */ aubio_biquad_t * new_aubio_biquad(lsmp_t b1, lsmp_t b2, lsmp_t b3, lsmp_t a2, lsmp_t a3); /** delete biquad filter \param b biquad object to delete */ void del_aubio_biquad(aubio_biquad_t * b); #ifdef __cplusplus } #endif #endif /*BIQUAD_H*/