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dll.h
/* Simple DLL */
/* SPDX-FileCopyrightText: Copyright © 2019 Wim Taymans */
/* SPDX-License-Identifier: MIT */
#ifndef SPA_DLL_H
#define SPA_DLL_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stddef.h>
#include <math.h>
#define SPA_DLL_BW_MAX 0.128
#define SPA_DLL_BW_MIN 0.016
struct spa_dll {
double bw;
double z1, z2, z3;
double w0, w1, w2;
};
static inline void spa_dll_init(struct spa_dll *dll)
{
dll->bw = 0.0;
dll->z1 = dll->z2 = dll->z3 = 0.0;
}
static inline void spa_dll_set_bw(struct spa_dll *dll, double bw, unsigned period, unsigned rate)
{
double w = 2 * M_PI * bw * period / rate;
dll->w0 = 1.0 - exp (-20.0 * w);
dll->w1 = w * 1.5 / period;
dll->w2 = w / 1.5;
dll->bw = bw;
}
static inline double spa_dll_update(struct spa_dll *dll, double err)
{
dll->z1 += dll->w0 * (dll->w1 * err - dll->z1);
dll->z2 += dll->w0 * (dll->z1 - dll->z2);
dll->z3 += dll->w2 * dll->z2;
return 1.0 - (dll->z2 + dll->z3);
}
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* SPA_DLL_H */
spa_dll
Definition dll.h:24
spa_dll::z2
double z2
Definition dll.h:26
spa_dll::z1
double z1
Definition dll.h:26
spa_dll::w2
double w2
Definition dll.h:27
spa_dll::z3
double z3
Definition dll.h:26
spa_dll::w0
double w0
Definition dll.h:27
spa_dll::bw
double bw
Definition dll.h:25
spa_dll::w1
double w1
Definition dll.h:27