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/*
dsp/Sine.h
Copyright 2003-4 Tim Goetze <tim@quitte.de>
http://quitte.de/dsp/
direct form I recursive sin() generator.
*/
/*
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., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA or point your web browser to http://www.gnu.org.
*/
#ifndef _DSP_SINE_H_
#define _DSP_SINE_H_
namespace DSP {
class Sine
{
protected:
int z;
d_float y[2];
d_float b;
public:
Sine()
{
b = 0;
y[0] = y[1] = 0;
z = 0;
}
Sine (double f, double fs, double phase)
{
set_f (f, fs, phase);
}
Sine (double omega, double phase = 0.)
{
set_f (omega, phase);
}
inline void set_f (double f, double fs, double phase)
{
set_f (f * M_PI / fs, phase);
}
inline void set_f (double w, double phase)
{
b = 2 * cos (w);
y[0] = sin (phase - w);
y[1] = sin (phase - w * 2);
z = 0;
}
/* advance and return 1 sample */
inline double get()
{
register double s = b * y[z];
z ^= 1;
s -= y[z];
return y[z] = s;
}
double get_phase()
{
double x0 = y[z], x1 = b * y[z] - y[z^1];
double phi = asin (x0);
/* slope is falling, we're into the 2nd half. */
if (x1 < x0)
return M_PI - phi;
return phi;
}
};
} /* namespace DSP */
#endif /* _DSP_SINE_H_ */
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