ref: ab0b69badbf2cf070a8c32070389fb878bac7571
parent: ebfbd151bf2aaf1293748fc3b085610e03aa65b2
author: Paul Brossier <piem@altern.org>
date: Wed May 17 15:43:27 EDT 2006
add doc to biquad and filter add doc to biquad and filter
--- a/src/biquad.h
+++ b/src/biquad.h
@@ -21,20 +21,49 @@
#define BIQUAD_H
/** \file
- * biquad filter
- *
- * \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$
- */
+ 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);
#ifdef __cplusplus
--- a/src/filter.h
+++ b/src/filter.h
@@ -21,22 +21,68 @@
#define FILTER_H
/** \file
- * filter
- *
- * \f$ y[n] = b_1 x[n] + ... + b_{order} x[n-order] -- * a_2 y[n-1] - ... - a_{order} y[n-order]\f$- */
+ Infinite Impulse Response filter
+
+ This file implements IIR filters of any order:
+
+ \f$ y[n] = b_1 x[n] + ... + b_{order} x[n-order] -+ a_2 y[n-1] - ... - a_{order} y[n-order]\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
+/** IIR filter object */
typedef struct _aubio_filter_t aubio_filter_t;
+
+/** filter input vector (in-place)
+
+ \param b biquad object as returned by new_aubio_biquad
+ \param in input vector to filter
+
+*/
void aubio_filter_do(aubio_filter_t * b, fvec_t * in);
+/** filter input vector (out-of-place)
+
+ \param b biquad object as returned by new_aubio_biquad
+ \param in input vector to filter
+ \param out output vector to store filtered input
+
+*/
void aubio_filter_do_outplace(aubio_filter_t * b, fvec_t * in, fvec_t * out);
+/** 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_filter_do_filtfilt(aubio_filter_t * b, fvec_t * in, fvec_t * tmp);
+/** create new IIR filter
+
+ \param b vector of forward coefficients
+ \param a vector of feedback coefficients
+ \param order order of the filter (number of coefficients)
+
+*/
aubio_filter_t * new_aubio_filter(uint_t samplerate, uint_t order);
+/** create a new A-design filter
+
+ \param samplerate sampling-rate of the signal to filter
+
+*/
aubio_filter_t * new_aubio_adsgn_filter(uint_t samplerate);
+/** create a new C-design filter
+
+ \param samplerate sampling-rate of the signal to filter
+
+*/
aubio_filter_t * new_aubio_cdsgn_filter(uint_t samplerate);
#ifdef __cplusplus