Mercurial > hg > audiostuff

comparison spandsp-0.0.3/spandsp-0.0.3/tests/line_model.h @ 5:f762bf195c4b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
import spandsp-0.0.3
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 16:00:21 +0200
parents
children
comparison
equal deleted inserted replaced
4:26cd8f1ef0b1 5:f762bf195c4b
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * line_model.h - Model a telephone line.
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2004 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2, as
14 * published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: line_model.h,v 1.12 2006/10/24 13:45:29 steveu Exp $
26 */
27
28 /*! \file */
29
30 /*! \page line_model_page Telephone line model
31 \section line_model_page_sec_1 What does it do?
32 The telephone line modelling module provides simple modelling of one way and two
33 way telephone lines.
34
35 The path being modelled is:
36
37 - terminal
38 - | < hybrid echo (2-way models)
39 - |
40 - | < noise and filtering
41 - |
42 - | < hybrid echo (2-way models)
43 - CO
44 - |
45 - | < A-law distortion + bulk delay
46 - |
47 - CO
48 - | < hybrid echo (2-way models)
49 - |
50 - | < noise and filtering
51 - |
52 - | < hybrid echo (2-way models)
53 - terminal
54 */
55
56 #if !defined(_LINE_MODEL_H_)
57 #define _LINE_MODEL_H_
58
59 #define LINE_FILTER_SIZE 129
60
61 /*!
62 One way line model descriptor. This holds the complete state of
63 a line model with transmission in only one direction.
64 */
65 typedef struct
66 {
67 codec_munge_state_t *munge;
68
69 /*! The coefficients for the near end analogue section simulation filter */
70 float *near_filter;
71 /*! The number of coefficients for the near end analogue section simulation filter */
72 int near_filter_len;
73 /*! Last transmitted samples (ring buffer, used by the line filter) */
74 float near_buf[LINE_FILTER_SIZE];
75 /*! Pointer of the last transmitted sample in buf */
76 int near_buf_ptr;
77 /*! The noise source for local analogue section of the line */
78 awgn_state_t near_noise;
79
80 /*! The bulk delay of the path, in samples */
81 int bulk_delay;
82 /*! A pointer to the current write position in the bulk delay store. */
83 int bulk_delay_ptr;
84 /*! The data store for simulating the bulk delay */
85 int16_t bulk_delay_buf[8000];
86
87 /*! The coefficients for the far end analogue section simulation filter */
88 float *far_filter;
89 /*! The number of coefficients for the far end analogue section simulation filter */
90 int far_filter_len;
91 /*! Last transmitted samples (ring buffer, used by the line filter) */
92 float far_buf[LINE_FILTER_SIZE];
93 /*! Pointer of the last transmitted sample in buf */
94 int far_buf_ptr;
95 /*! The noise source for distant analogue section of the line */
96 awgn_state_t far_noise;
97
98 /*! The scaling factor for the local CPE hybrid echo */
99 float near_cpe_hybrid_echo;
100 /*! The scaling factor for the local CO hybrid echo */
101 float near_co_hybrid_echo;
102
103 /*! The scaling factor for the far CPE hybrid echo */
104 float far_cpe_hybrid_echo;
105 /*! The scaling factor for the far CO hybrid echo */
106 float far_co_hybrid_echo;
107 } one_way_line_model_state_t;
108
109 /*!
110 Two way line model descriptor. This holds the complete state of
111 a line model with transmission in both directions.
112 */
113 typedef struct
114 {
115 one_way_line_model_state_t line1;
116 one_way_line_model_state_t line2;
117 float fout1;
118 float fout2;
119 } both_ways_line_model_state_t;
120
121 #ifdef __cplusplus
122 extern "C" {
123 #endif
124
125 void both_ways_line_model(both_ways_line_model_state_t *s,
126 int16_t *output1,
127 const int16_t *input1,
128 int16_t *output2,
129 const int16_t *input2,
130 int samples);
131
132 both_ways_line_model_state_t *both_ways_line_model_init(int model1,
133 float noise1,
134 int model2,
135 float noise2,
136 int codec);
137
138 int both_ways_line_model_release(both_ways_line_model_state_t *s);
139
140 void one_way_line_model(one_way_line_model_state_t *s,
141 int16_t *output,
142 const int16_t *input,
143 int samples);
144
145 one_way_line_model_state_t *one_way_line_model_init(int model, float noise, int codec);
146
147 int one_way_line_model_release(one_way_line_model_state_t *s);
148
149 #ifdef __cplusplus
150 }
151 #endif
152
153 #endif
154 /*- End of file ------------------------------------------------------------*/

Repositories maintained by Peter Meerwald, pmeerw@pmeerw.net.