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Diffstat (limited to 'apps/plugins/pdbox/PDa/extra/notch.c')
-rw-r--r--apps/plugins/pdbox/PDa/extra/notch.c178
1 files changed, 178 insertions, 0 deletions
diff --git a/apps/plugins/pdbox/PDa/extra/notch.c b/apps/plugins/pdbox/PDa/extra/notch.c
new file mode 100644
index 0000000000..49be753ff2
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1/* (C) Guenter Geiger <geiger@epy.co.at> */
2
3
4/*
5
6 These filter coefficients computations are taken from
7 http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt
8
9 written by Robert Bristow-Johnson
10
11*/
12
13#include "m_pd.h"
14#ifdef NT
15#pragma warning( disable : 4244 )
16#pragma warning( disable : 4305 )
17#endif
18#include <math.h>
19#include "filters.h"
20
21
22
23/* ------------------- notch ----------------------------*/
24
25static t_class *notch_class;
26
27void notch_bang(t_rbjfilter *x)
28{
29 t_atom at[5];
30 t_float omega = e_omega(x->x_freq,x->x_rate);
31 t_float alpha = e_alpha(x->x_bw* 0.01,omega);
32 t_float b1 = -2.*cos(omega);
33 t_float b0 = 1;
34 t_float b2 = b0;
35 t_float a0 = 1 + alpha;
36 t_float a1 = -2.*cos(omega);
37 t_float a2 = 1 - alpha;
38
39/* post("bang %f %f %f",x->x_freq, x->x_gain, x->x_bw); */
40
41 if (!check_stability(-a1/a0,-a2/a0,b0/a0,b1/a0,b2/a0)) {
42 post("notch: filter unstable -> resetting");
43 a0=1.;a1=0.;a2=0.;
44 b0=1.;b1=0.;b2=0.;
45 }
46
47 SETFLOAT(at,-a1/a0);
48 SETFLOAT(at+1,-a2/a0);
49 SETFLOAT(at+2,b0/a0);
50 SETFLOAT(at+3,b1/a0);
51 SETFLOAT(at+4,b2/a0);
52
53 outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
54}
55
56
57void notch_float(t_rbjfilter *x,t_floatarg f)
58{
59 x->x_freq = f;
60 notch_bang(x);
61}
62
63
64static void *notch_new(t_floatarg f,t_floatarg bw)
65{
66 t_rbjfilter *x = (t_rbjfilter *)pd_new(notch_class);
67
68 x->x_rate = 44100.0;
69 outlet_new(&x->x_obj,&s_float);
70/* floatinlet_new(&x->x_obj, &x->x_gain); */
71 floatinlet_new(&x->x_obj, &x->x_bw);
72 if (f > 0.) x->x_freq = f;
73 if (bw > 0.) x->x_bw = bw;
74 return (x);
75}
76
77
78void notch_setup(void)
79{
80 notch_class = class_new(gensym("notch"), (t_newmethod)notch_new, 0,
81 sizeof(t_rbjfilter), 0,A_DEFFLOAT,A_DEFFLOAT,0);
82 class_addbang(notch_class,notch_bang);
83 class_addfloat(notch_class,notch_float);
84}
85
86
87
88
89
90/* (C) Guenter Geiger <geiger@epy.co.at> */
91
92
93/*
94
95 These filter coefficients computations are taken from
96 http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt
97
98 written by Robert Bristow-Johnson
99
100*/
101
102#include "m_pd.h"
103#ifdef NT
104#pragma warning( disable : 4244 )
105#pragma warning( disable : 4305 )
106#endif
107#include <math.h>
108#include "filters.h"
109
110
111
112/* ------------------- notch ----------------------------*/
113
114static t_class *notch_class;
115
116void notch_bang(t_rbjfilter *x)
117{
118 t_atom at[5];
119 t_float omega = e_omega(x->x_freq,x->x_rate);
120 t_float alpha = e_alpha(x->x_bw* 0.01,omega);
121 t_float b1 = -2.*cos(omega);
122 t_float b0 = 1;
123 t_float b2 = b0;
124 t_float a0 = 1 + alpha;
125 t_float a1 = -2.*cos(omega);
126 t_float a2 = 1 - alpha;
127
128/* post("bang %f %f %f",x->x_freq, x->x_gain, x->x_bw); */
129
130 if (!check_stability(-a1/a0,-a2/a0,b0/a0,b1/a0,b2/a0)) {
131 post("notch: filter unstable -> resetting");
132 a0=1.;a1=0.;a2=0.;
133 b0=1.;b1=0.;b2=0.;
134 }
135
136 SETFLOAT(at,-a1/a0);
137 SETFLOAT(at+1,-a2/a0);
138 SETFLOAT(at+2,b0/a0);
139 SETFLOAT(at+3,b1/a0);
140 SETFLOAT(at+4,b2/a0);
141
142 outlet_list(x->x_obj.ob_outlet,&s_list,5,at);
143}
144
145
146void notch_float(t_rbjfilter *x,t_floatarg f)
147{
148 x->x_freq = f;
149 notch_bang(x);
150}
151
152
153static void *notch_new(t_floatarg f,t_floatarg bw)
154{
155 t_rbjfilter *x = (t_rbjfilter *)pd_new(notch_class);
156
157 x->x_rate = 44100.0;
158 outlet_new(&x->x_obj,&s_float);
159/* floatinlet_new(&x->x_obj, &x->x_gain); */
160 floatinlet_new(&x->x_obj, &x->x_bw);
161 if (f > 0.) x->x_freq = f;
162 if (bw > 0.) x->x_bw = bw;
163 return (x);
164}
165
166
167void notch_setup(void)
168{
169 notch_class = class_new(gensym("notch"), (t_newmethod)notch_new, 0,
170 sizeof(t_rbjfilter), 0,A_DEFFLOAT,A_DEFFLOAT,0);
171 class_addbang(notch_class,notch_bang);
172 class_addfloat(notch_class,notch_float);
173}
174
175
176
177
178