retronetworking
/
freeswitch
13
0
Fork 0
Code Pull Requests Releases Activity
freeswitch/libs/spandsp/src/dds_int.c

345 lines
8.4 KiB
C
Raw Blame History

/*
* SpanDSP - a series of DSP components for telephony
*
* dds.c
*
* Written by Steve Underwood <steveu@coppice.org>
*
* Copyright (C) 2003 Steve Underwood
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1,
* as published by the Free Software Foundation.
*
* 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*! \file */
#if defined(HAVE_CONFIG_H)
#include "config.h"
#endif
#include <inttypes.h>
#if defined(HAVE_TGMATH_H)
#include <tgmath.h>
#endif
#if defined(HAVE_MATH_H)
#include <math.h>
#endif
#include "floating_fudge.h"
#include "spandsp/telephony.h"
#include "spandsp/complex.h"
#include "spandsp/dds.h"
#if !defined(M_PI)
# define M_PI 3.14159265358979323846 /* pi */
#endif
/* In a A-law or u-law channel, a 128 step sine table is adequate to keep the spectral
mess due to the DDS at a similar level to the spectral mess due to the A-law or u-law
compression. */
#define SLENK 7
#define DDS_STEPS (1 << SLENK)
#define DDS_SHIFT (32 - 2 - SLENK)
/* This is a simple set of direct digital synthesis (DDS) functions to generate sine
waves. This version uses a 128 entry sin/cos table to cover one quadrant. */
static const int16_t sine_table[DDS_STEPS + 1] =
{
201,
603,
1005,
1407,
1809,
2210,
2611,
3012,
3412,
3812,
4211,
4609,
5007,
5404,
5800,
6195,
6590,
6983,
7376,
7767,
8157,
8546,
8933,
9319,
9704,
10088,
10469,
10850,
11228,
11605,
11980,
12354,
12725,
13095,
13463,
13828,
14192,
14553,
14912,
15269,
15624,
15976,
16326,
16673,
17018,
17361,
17700,
18037,
18372,
18703,
19032,
19358,
19681,
20001,
20318,
20632,
20943,
21251,
21555,
21856,
22154,
22449,
22740,
23028,
23312,
23593,
23870,
24144,
24414,
24680,
24943,
25202,
25457,
25708,
25956,
26199,
26439,
26674,
26906,
27133,
27357,
27576,
27791,
28002,
28209,
28411,
28610,
28803,
28993,
29178,
29359,
29535,
29707,
29875,
30038,
30196,
30350,
30499,
30644,
30784,
30920,
31050,
31177,
31298,
31415,
31527,
31634,
31737,
31834,
31927,
32015,
32099,
32177,
32251,
32319,
32383,
32442,
32496,
32546,
32590,
32629,
32664,
32693,
32718,
32738,
32753,
32762,
32767,
32767
};
SPAN_DECLARE(int32_t) dds_phase_rate(float frequency)
{
return (int32_t) (frequency*65536.0f*65536.0f/SAMPLE_RATE);
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(float) dds_frequency(int32_t phase_rate)
{
return (float) phase_rate*(float) SAMPLE_RATE/(65536.0f*65536.0f);
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(int16_t) dds_scaling_dbm0(float level)
{
return (int16_t) (powf(10.0f, (level - DBM0_MAX_SINE_POWER)/20.0f)*32767.0f);
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(int16_t) dds_scaling_dbov(float level)
{
return (int16_t) (powf(10.0f, (level - DBOV_MAX_SINE_POWER)/20.0f)*32767.0f);
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(int16_t) dds_lookup(uint32_t phase)
{
uint32_t step;
int16_t amp;
phase >>= DDS_SHIFT;
step = phase & (DDS_STEPS - 1);
if ((phase & DDS_STEPS))
step = DDS_STEPS - step;
amp = sine_table[step];
if ((phase & (2*DDS_STEPS)))
amp = -amp;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(int16_t) dds_offset(uint32_t phase_acc, int32_t phase_offset)
{
return dds_lookup(phase_acc + phase_offset);
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(void) dds_advance(uint32_t *phase_acc, int32_t phase_rate)
{
*phase_acc += phase_rate;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(int16_t) dds(uint32_t *phase_acc, int32_t phase_rate)
{
int16_t amp;
amp = dds_lookup(*phase_acc);
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(int16_t) dds_mod(uint32_t *phase_acc, int32_t phase_rate, int16_t scale, int32_t phase)
{
int16_t amp;
amp = (int16_t) (((int32_t) dds_lookup(*phase_acc + phase)*scale) >> 15);
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi_t) dds_lookup_complexi(uint32_t phase)
{
return complex_seti(dds_lookup(phase + (1 << 30)), dds_lookup(phase));
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi_t) dds_complexi(uint32_t *phase_acc, int32_t phase_rate)
{
complexi_t amp;
amp = complex_seti(dds_lookup(*phase_acc + (1 << 30)), dds_lookup(*phase_acc));
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi_t) dds_complexi_mod(uint32_t *phase_acc, int32_t phase_rate, int16_t scale, int32_t phase)
{
complexi_t amp;
amp = complex_seti(((int32_t) dds_lookup(*phase_acc + phase + (1 << 30))*scale) >> 15,
((int32_t) dds_lookup(*phase_acc + phase)*scale) >> 15);
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi16_t) dds_lookup_complexi16(uint32_t phase)
{
return complex_seti16(dds_lookup(phase + (1 << 30)), dds_lookup(phase));
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi16_t) dds_complexi16(uint32_t *phase_acc, int32_t phase_rate)
{
complexi16_t amp;
amp = complex_seti16(dds_lookup(*phase_acc + (1 << 30)), dds_lookup(*phase_acc));
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi16_t) dds_complexi16_mod(uint32_t *phase_acc, int32_t phase_rate, int16_t scale, int32_t phase)
{
complexi16_t amp;
amp = complex_seti16((int16_t) (((int32_t) dds_lookup(*phase_acc + phase + (1 << 30))*scale) >> 15),
(int16_t) (((int32_t) dds_lookup(*phase_acc + phase)*scale) >> 15));
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi32_t) dds_lookup_complexi32(uint32_t phase)
{
return complex_seti32(dds_lookup(phase + (1 << 30)), dds_lookup(phase));
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi32_t) dds_complexi32(uint32_t *phase_acc, int32_t phase_rate)
{
complexi32_t amp;
amp = complex_seti32(dds_lookup(*phase_acc + (1 << 30)), dds_lookup(*phase_acc));
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
SPAN_DECLARE(complexi32_t) dds_complexi32_mod(uint32_t *phase_acc, int32_t phase_rate, int16_t scale, int32_t phase)
{
complexi32_t amp;
amp = complex_seti32(((int32_t) dds_lookup(*phase_acc + phase + (1 << 30))*scale) >> 15,
((int32_t) dds_lookup(*phase_acc + phase)*scale) >> 15);
*phase_acc += phase_rate;
return amp;
}
/*- End of function --------------------------------------------------------*/
/*- End of file ------------------------------------------------------------*/
View Git Blame Copy Permalink