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5
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1 /*
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2 * SpanDSP - a series of DSP components for telephony
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3 *
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4 * line_model.c - Model a telephone line.
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5 *
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6 * Written by Steve Underwood <steveu@coppice.org>
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7 *
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8 * Copyright (C) 2004 Steve Underwood
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9 *
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10 * All rights reserved.
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11 *
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12 * This program is free software; you can redistribute it and/or modify
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13 * it under the terms of the GNU General Public License version 2, as
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14 * published by the Free Software Foundation.
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15 *
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16 * This program is distributed in the hope that it will be useful,
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17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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19 * GNU General Public License for more details.
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20 *
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21 * You should have received a copy of the GNU General Public License
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22 * along with this program; if not, write to the Free Software
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23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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24 *
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25 * $Id: line_model.c,v 1.21 2006/11/19 14:07:27 steveu Exp $
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26 */
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27
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28 #ifdef HAVE_CONFIG_H
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29 #include "config.h"
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30 #endif
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31
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32 #include <stdlib.h>
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33 #include <unistd.h>
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34 #include <inttypes.h>
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35 #include <string.h>
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36 #include <time.h>
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37 #include <stdio.h>
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38 #include <fcntl.h>
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39 #include <audiofile.h>
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40 #include <tiffio.h>
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41 #if defined(HAVE_TGMATH_H)
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42 #include <tgmath.h>
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43 #endif
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44 #if defined(HAVE_MATH_H)
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45 #define GEN_CONST
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46 #include <math.h>
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47 #endif
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48
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49 #include "spandsp.h"
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50 #include "spandsp/g168models.h"
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51
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52 #include "test_utils.h"
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53 #include "line_model.h"
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54 #include "line_models.h"
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55
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56 #if !defined(NULL)
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57 #define NULL (void *) 0
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58 #endif
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59
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60 float null_line_model[] =
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61 {
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62 0.0,
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63 0.0,
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64 0.0,
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65 0.0,
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66 0.0,
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67 0.0,
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68 0.0,
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69 0.0,
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70 0.0,
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71 0.0,
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72 0.0,
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73 0.0,
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74 0.0,
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75 0.0,
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76 0.0,
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77 0.0,
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78 0.0,
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79 0.0,
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80 0.0,
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81 0.0,
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82 0.0,
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83 0.0,
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84 0.0,
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85 0.0,
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86 0.0,
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87 0.0,
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88 0.0,
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89 0.0,
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90 0.0,
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91 0.0,
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92 0.0,
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93 0.0,
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94 0.0,
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95 0.0,
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96 0.0,
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97 0.0,
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98 0.0,
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99 0.0,
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100 0.0,
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101 0.0,
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102 0.0,
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103 0.0,
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104 0.0,
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105 0.0,
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106 0.0,
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107 0.0,
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108 0.0,
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109 0.0,
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110 0.0,
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111 0.0,
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112 0.0,
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113 0.0,
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114 0.0,
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115 0.0,
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116 0.0,
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117 0.0,
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118 0.0,
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119 0.0,
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120 0.0,
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121 0.0,
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122 0.0,
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123 0.0,
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124 0.0,
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125 0.0,
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126 0.0,
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127 0.0,
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128 0.0,
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129 0.0,
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130 0.0,
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131 0.0,
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132 0.0,
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133 0.0,
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134 0.0,
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135 0.0,
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136 0.0,
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137 0.0,
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138 0.0,
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139 0.0,
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140 0.0,
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141 0.0,
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142 0.0,
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143 0.0,
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144 0.0,
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145 0.0,
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146 0.0,
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147 0.0,
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148 0.0,
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149 0.0,
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150 0.0,
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151 0.0,
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152 0.0,
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153 0.0,
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154 0.0,
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155 0.0,
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156 0.0,
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157 0.0,
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158 0.0,
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159 0.0,
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160 0.0,
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161 0.0,
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162 0.0,
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163 0.0,
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164 0.0,
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165 0.0,
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166 0.0,
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167 0.0,
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168 0.0,
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169 0.0,
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170 0.0,
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171 0.0,
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172 0.0,
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173 0.0,
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174 0.0,
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175 0.0,
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176 0.0,
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177 0.0,
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178 0.0,
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179 0.0,
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180 0.0,
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181 0.0,
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182 0.0,
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183 0.0,
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184 0.0,
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185 0.0,
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186 0.0,
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187 0.0,
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188 0.0,
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189 0.0,
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190 1.0
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191 };
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192
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193 static float *models[] =
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194 {
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195 null_line_model, /* 0 */
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196 proakis_line_model,
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197 ad_1_edd_1_model,
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198 ad_1_edd_2_model,
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199 ad_1_edd_3_model,
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200 ad_5_edd_1_model, /* 5 */
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201 ad_5_edd_2_model,
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202 ad_5_edd_3_model,
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203 ad_6_edd_1_model,
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204 ad_6_edd_2_model,
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205 ad_6_edd_3_model, /* 10 */
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206 ad_7_edd_1_model,
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207 ad_7_edd_2_model,
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208 ad_7_edd_3_model,
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209 ad_8_edd_1_model,
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210 ad_8_edd_2_model, /* 15 */
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211 ad_8_edd_3_model,
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212 ad_9_edd_1_model,
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213 ad_9_edd_2_model,
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214 ad_9_edd_3_model
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215 };
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216
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217 static float calc_near_line_filter(one_way_line_model_state_t *s, float v)
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218 {
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219 float sum;
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220 int j;
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221 int p;
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222
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223 /* Add the sample in the filter buffer */
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224 p = s->near_buf_ptr;
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225 s->near_buf[p] = v;
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226 if (++p == s->near_filter_len)
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227 p = 0;
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228 s->near_buf_ptr = p;
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229
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230 /* Apply the filter */
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231 sum = 0;
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232 for (j = 0; j < s->near_filter_len; j++)
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233 {
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234 sum += s->near_filter[j]*s->near_buf[p];
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235 if (++p >= s->near_filter_len)
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236 p = 0;
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237 }
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238
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239 /* Add noise */
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240 sum += awgn(&s->near_noise);
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241
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242 return sum;
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243 }
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244 /*- End of function --------------------------------------------------------*/
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245
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246 static float calc_far_line_filter(one_way_line_model_state_t *s, float v)
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247 {
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248 float sum;
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249 int j;
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250 int p;
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251
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252 /* Add the sample in the filter buffer */
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253 p = s->far_buf_ptr;
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254 s->far_buf[p] = v;
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255 if (++p == s->far_filter_len)
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256 p = 0;
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257 s->far_buf_ptr = p;
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258
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259 /* Apply the filter */
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260 sum = 0;
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261 for (j = 0; j < s->far_filter_len; j++)
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262 {
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263 sum += s->far_filter[j]*s->far_buf[p];
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264 if (++p >= s->far_filter_len)
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265 p = 0;
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266 }
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267
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268 /* Add noise */
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269 sum += awgn(&s->far_noise);
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270
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271 return sum;
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272 }
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273 /*- End of function --------------------------------------------------------*/
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274
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275 void one_way_line_model(one_way_line_model_state_t *s,
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276 int16_t *output,
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277 const int16_t *input,
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278 int samples)
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279 {
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280 int i;
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281 float in;
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282 float out;
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283 float out1;
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284 int16_t amp[1];
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285
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286 /* The path being modelled is:
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287 terminal
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288 | < hybrid
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289 |
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290 | < noise and filtering
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291 |
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292 | < hybrid
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293 CO
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294 |
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295 | < A-law distortion + bulk delay
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296 |
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297 CO
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298 | < hybrid
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299 |
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300 | < noise and filtering
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301 |
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302 | < hybrid
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303 terminal
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304 */
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305 for (i = 0; i < samples; i++)
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306 {
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307 in = input[i];
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308
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309 /* Near end analogue section */
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310
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311 /* Line model filters & noise */
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312 out = calc_near_line_filter(s, in);
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313
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314 /* Long distance digital section */
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315
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316 amp[0] = out;
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317 codec_munge(s->munge, amp, 1);
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318 out = amp[0];
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319 /* Introduce the bulk delay of the long distance link. */
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320 out1 = s->bulk_delay_buf[s->bulk_delay_ptr];
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321 s->bulk_delay_buf[s->bulk_delay_ptr] = out;
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322 out = out1;
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323 if (++s->bulk_delay_ptr >= s->bulk_delay)
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324 s->bulk_delay_ptr = 0;
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325
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326 /* Far end analogue section */
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327
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328 /* Line model filters & noise */
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329 out = calc_far_line_filter(s, out);
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330
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331 output[i] = out;
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332 }
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333 }
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334 /*- End of function --------------------------------------------------------*/
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335
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336 void both_ways_line_model(both_ways_line_model_state_t *s,
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337 int16_t *output1,
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338 const int16_t *input1,
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339 int16_t *output2,
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340 const int16_t *input2,
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341 int samples)
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342 {
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343 int i;
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344 float in1;
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345 float in2;
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346 float out1;
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347 float out2;
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348 float tmp1;
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349 float tmp2;
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350 int16_t amp[1];
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351
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352 /* The path being modelled is:
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353 terminal
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354 | < hybrid echo
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355 |
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356 | < noise and filtering
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357 |
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358 | < hybrid echo
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359 CO
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360 |
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361 | < A-law distortion + bulk delay
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362 |
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363 CO
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364 | < hybrid echo
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365 |
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366 | < noise and filtering
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367 |
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368 | < hybrid echo
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369 terminal
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370 */
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371 for (i = 0; i < samples; i++)
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372 {
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373 in1 = input1[i];
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374 in2 = input2[i];
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375
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376 /* Near end analogue sections */
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377 /* Echo from each terminal's CO hybrid */
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378 tmp1 = in1 + s->fout2*s->line1.near_co_hybrid_echo;
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379 tmp2 = in2 + s->fout1*s->line2.near_co_hybrid_echo;
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380
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381 /* Line model filters & noise */
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382 s->fout1 = calc_near_line_filter(&s->line1, tmp1);
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383 s->fout2 = calc_near_line_filter(&s->line2, tmp2);
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384
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385 /* Long distance digital section */
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386
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387 /* Introduce distortion due to A-law or u-law munging. */
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388 amp[0] = s->fout1;
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389 codec_munge(s->line1.munge, amp, 1);
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390 s->fout1 = amp[0];
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391
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392 amp[0] = s->fout2;
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393 codec_munge(s->line2.munge, amp, 1);
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394 s->fout2 = amp[0];
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395
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396 /* Introduce the bulk delay of the long distance digital link. */
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397 out1 = s->line1.bulk_delay_buf[s->line1.bulk_delay_ptr];
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398 s->line1.bulk_delay_buf[s->line1.bulk_delay_ptr] = s->fout1;
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399 s->fout1 = out1;
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400 if (++s->line1.bulk_delay_ptr >= s->line1.bulk_delay)
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401 s->line1.bulk_delay_ptr = 0;
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402
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403 out2 = s->line2.bulk_delay_buf[s->line2.bulk_delay_ptr];
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404 s->line2.bulk_delay_buf[s->line2.bulk_delay_ptr] = s->fout2;
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405 s->fout2 = out2;
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406 if (++s->line2.bulk_delay_ptr >= s->line2.bulk_delay)
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407 s->line2.bulk_delay_ptr = 0;
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408
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409 /* Far end analogue sections */
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410
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411 /* Echo from each terminal's own hybrid */
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412 out1 += in2*s->line1.far_cpe_hybrid_echo;
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413 out2 += in1*s->line2.far_cpe_hybrid_echo;
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414
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415 /* Line model filters & noise */
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416 out1 = calc_far_line_filter(&s->line1, out1);
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417 out2 = calc_far_line_filter(&s->line2, out2);
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418
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419 output1[i] = fsaturate(out1);
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420 output2[i] = fsaturate(out2);
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421 }
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422 }
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423 /*- End of function --------------------------------------------------------*/
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424
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425 one_way_line_model_state_t *one_way_line_model_init(int model, float noise, int codec)
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426 {
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427 one_way_line_model_state_t *s;
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428
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429 if ((s = (one_way_line_model_state_t *) malloc(sizeof(*s))) == NULL)
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430 return NULL;
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431 memset(s, 0, sizeof(*s));
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432
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433 s->bulk_delay = 8;
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434 s->bulk_delay_ptr = 0;
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435
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436 s->munge = codec_munge_init(codec);
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437
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438 s->near_filter = models[model];
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439 s->near_filter_len = 129;
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440
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441 s->far_filter = models[model];
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442 s->far_filter_len = 129;
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443
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444 awgn_init_dbm0(&s->near_noise, 1234567, noise);
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445 awgn_init_dbm0(&s->far_noise, 1234567, noise);
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446 return s;
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447 }
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448 /*- End of function --------------------------------------------------------*/
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449
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450 int one_way_line_model_release(one_way_line_model_state_t *s)
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451 {
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452 free(s);
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453 return 0;
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454 }
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455 /*- End of function --------------------------------------------------------*/
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456
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457 both_ways_line_model_state_t *both_ways_line_model_init(int model1,
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458 float noise1,
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459 int model2,
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460 float noise2,
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461 int codec)
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462 {
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463 float echo_level;
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464 both_ways_line_model_state_t *s;
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465
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466 if ((s = (both_ways_line_model_state_t *) malloc(sizeof(*s))) == NULL)
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467 return NULL;
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468 memset(s, 0, sizeof(*s));
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469
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470 s->line1.munge = codec_munge_init(codec);
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471 s->line2.munge = codec_munge_init(codec);
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472
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473 s->line1.bulk_delay = 8;
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474 s->line2.bulk_delay = 8;
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475
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476 s->line1.bulk_delay_ptr = 0;
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477 s->line2.bulk_delay_ptr = 0;
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478
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479 s->line1.near_filter = models[model1];
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480 s->line1.near_filter_len = 129;
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481 s->line2.near_filter = models[model2];
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482 s->line2.near_filter_len = 129;
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483
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484 s->line1.far_filter = models[model1];
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485 s->line1.far_filter_len = 129;
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486 s->line2.far_filter = models[model2];
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487 s->line2.far_filter_len = 129;
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488
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489 awgn_init_dbm0(&s->line1.near_noise, 1234567, noise1);
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490 awgn_init_dbm0(&s->line2.near_noise, 7654321, noise2);
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491
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492 awgn_init_dbm0(&s->line1.far_noise, 1234567, noise1);
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493 awgn_init_dbm0(&s->line2.far_noise, 7654321, noise2);
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494
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495 /* Echos */
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496 echo_level = -15; /* in dB */
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497 s->line1.near_co_hybrid_echo = pow(10, echo_level/20.0);
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498 s->line2.near_co_hybrid_echo = pow(10, echo_level/20.0);
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499 s->line1.near_cpe_hybrid_echo = pow(10, echo_level/20.0);
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500 s->line2.near_cpe_hybrid_echo = pow(10, echo_level/20.0);
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501
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502 return s;
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503 }
|
|
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504 /*- End of function --------------------------------------------------------*/
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505
|
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506 int both_ways_line_model_release(both_ways_line_model_state_t *s)
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|
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507 {
|
|
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508 free(s);
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|
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509 return 0;
|
|
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510 }
|
|
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511 /*- End of function --------------------------------------------------------*/
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512 /*- End of file ------------------------------------------------------------*/
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