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/*
SuperCollider real time audio synthesis system
Copyright (c) 2002 James McCartney. All rights reserved.
http://www.audiosynth.com
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
#include "SC_CoreAudio.h"
#include <stdarg.h>
#include "SC_Prototypes.h"
#include "SC_HiddenWorld.h"
#include "SC_WorldOptions.h"
#include <stdlib.h>
#ifdef _WIN32
#include "SC_Win32Utils.h"
#else
#include <sys/time.h>
#endif
*/
// =====================================================================
// SC_TimeDLL
//
// Delay-Locked-Loop after
// Fons Adriaensen, "Using a DLL to filter time"
#ifndef M_PI
# define M_PI 3.14159265358979323846
#endif
#define SC_TIME_DLL_BW 0.012
class SC_TimeDLL {
public:
SC_TimeDLL(): m_b(0.), m_c(0.), m_t0(0.), m_t1(0.), m_e2(0.), m_np(0), m_ei(0.), m_ec(0) {}
void Reset(double sampleRate, uint32_t periodFrames, double bandWidth, double t) {
// compute coefficients
m_np = periodFrames;
m_b = 2 * M_PI * bandWidth * m_np / sampleRate;
m_c = m_b * m_b / 2.;
// initialize filter
double tp = m_np / sampleRate;
m_e2 = tp;
m_t0 = t;
m_t1 = t + tp;
// initialize statistics
m_ei = 0.;
m_ec = 0;
}
void Update(double t) {
// compute error
double e = m_e = t - m_t1;
// update filter
m_t0 = m_t1;
m_t1 += m_b * e + m_e2;
m_e2 += m_c * e;
// collect statistics
m_ei += e;
m_ec++;
}
double PeriodTime() const { return m_t0; }
double NextPeriodTime() const { return m_t1; }
double Period() const { return m_t1 - m_t0; }
double SampleRate() const { return m_np / Period(); }
double Error() const { return m_e; }
double AvgError() const { return m_ec > 0 ? m_ei / m_ec : 0; }
private:
double m_b, m_c;
double m_t0, m_t1, m_e, m_e2;
int m_np;
double m_ei;
int m_ec;
};
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