block_filter_lp.c 3.06 KB
Newer Older
Jeroen Vreeken's avatar
Jeroen Vreeken committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
/*
	Copyright Jeroen Vreeken (pe1rxq@amsat.org), 2007
	Copyright Stichting C.A. Muller Radioastronomiestation, 2007

	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 3 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, see <http://www.gnu.org/licenses/>.

 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

Jeroen Vreeken's avatar
Jeroen Vreeken committed
24
25
#include <controller/controller_block.h>

Jeroen Vreeken's avatar
Jeroen Vreeken committed
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47

/*
       inputs      outputs
       nr name     nr name

     ----------------------
     |                    |
  ---| 0  in       0  out |----
     |	                  |
     ----------------------
     
 */

struct controller_block_private {
	float *input0;
	float out;
	
	float alpha;
	float t;
	float tau;
};

48
static void filter_lp_calculate(struct controller_block *lp)
Jeroen Vreeken's avatar
Jeroen Vreeken committed
49
{
50
51
52
53
54
55
56
	struct controller_block_private *priv = lp->private;
	float alpha = priv->alpha;
	float out = priv->out;
	
	out *= 1.0 - alpha;
	out += *lp->private->input0 * alpha;
	priv->out = out;
Jeroen Vreeken's avatar
Jeroen Vreeken committed
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
}

static struct controller_block_param_list params[] = {
	{ "tau", true },
	{ "t",   true },
	{ NULL },
};

static void param_get(struct controller_block *lp, int param, void *val)
{
	switch (param) {
		case 0:
			*(float*)val = lp->private->tau;
			break;
		case 1:
			*(float*)val = lp->private->t;
			break;
	}
}

static void param_set(struct controller_block *lp, int param, va_list val)
{
	switch (param) {
		case 0:
			lp->private->tau = va_arg(val, double);
			break;
		case 1:
			lp->private->t = va_arg(val, double);
			break;
	}

	if (lp->private->t == 0.0)
		lp->private->t = 1.0;

	lp->private->alpha =
	    lp->private->t / (lp->private->t + lp->private->tau);
}

95
96
97
98
99
100
101
102
103
104
static struct controller_block_interm_list interms[] = {
	{ "in", CONTROLLER_BLOCK_TERM_FLOAT, offsetof(struct controller_block_private, input0) },
	{ NULL }
};

static struct controller_block_outterm_list outterms[] = {
	{ "out", CONTROLLER_BLOCK_TERM_FLOAT, offsetof(struct controller_block_private, out) },
	{ NULL }
};

Jeroen Vreeken's avatar
Jeroen Vreeken committed
105
106
107
108
struct controller_block * block_filter_lp_create(char *name)
{
	struct controller_block *lp;
	
109
	if (!(lp = controller_block_alloc("filter_lp", name, sizeof(struct controller_block_private))))
Jeroen Vreeken's avatar
Jeroen Vreeken committed
110
111
112
113
114
115
116
		return NULL;

	lp->private->out = 0.0;
	lp->private->t = 1.0;
	lp->private->tau = 1.0;
	lp->private->alpha = 0.0;

117
118
119
120
121
122
123
	if (controller_block_interm_list_init(lp, interms))
		goto err_block;

	if (controller_block_outterm_list_init(lp, outterms))
		goto err_block;

	lp->calculate = filter_lp_calculate;
Jeroen Vreeken's avatar
Jeroen Vreeken committed
124
125

	if (controller_block_param_list_init(lp, params))
126
		goto err_block;
Jeroen Vreeken's avatar
Jeroen Vreeken committed
127
128
129
130
131
132
133

	lp->param_get = param_get;
	lp->param_set = param_set;

	controller_block_add(lp);
	return lp;

134
135
err_block:
	controller_block_free(lp);
Jeroen Vreeken's avatar
Jeroen Vreeken committed
136
137
	return NULL;
}