--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/spandsp-sim/line_model.c	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,568 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * line_model.c - Model a telephone line.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2004 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: line_model.c,v 1.14 2009/09/23 16:02:59 steveu Exp $
+ */
+
+#if defined(HAVE_CONFIG_H)
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <string.h>
+#include <time.h>
+#include <stdio.h>
+#include <fcntl.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#define GEN_CONST
+#include <math.h>
+#endif
+#include "floating_fudge.h"
+
+#define SPANDSP_EXPOSE_INTERNAL_STRUCTURES
+#include "spandsp.h"
+#include "spandsp-sim.h"
+#include "spandsp/g168models.h"
+
+#if !defined(NULL)
+#define NULL (void *) 0
+#endif
+
+static const float null_line_model[] =
+{
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        0.0,
+        1.0
+};
+
+SPAN_DECLARE_DATA const float *line_models[] =
+{
+    null_line_model,        /* 0 */
+    proakis_line_model,
+    ad_1_edd_1_model,
+    ad_1_edd_2_model,
+    ad_1_edd_3_model,
+    ad_5_edd_1_model,       /* 5 */
+    ad_5_edd_2_model,
+    ad_5_edd_3_model,
+    ad_6_edd_1_model,
+    ad_6_edd_2_model,
+    ad_6_edd_3_model,       /* 10 */
+    ad_7_edd_1_model,
+    ad_7_edd_2_model,
+    ad_7_edd_3_model,
+    ad_8_edd_1_model,
+    ad_8_edd_2_model,       /* 15 */
+    ad_8_edd_3_model,
+    ad_9_edd_1_model,
+    ad_9_edd_2_model,
+    ad_9_edd_3_model
+};
+
+static float calc_near_line_filter(one_way_line_model_state_t *s, float v)
+{
+    float sum;
+    int j;
+    int p;
+
+    /* Add the sample in the filter buffer */
+    p = s->near_buf_ptr;
+    s->near_buf[p] = v;
+    if (++p == s->near_filter_len)
+        p = 0;
+    s->near_buf_ptr = p;
+    
+    /* Apply the filter */
+    sum = 0.0f;
+    for (j = 0;  j < s->near_filter_len;  j++)
+    {
+        sum += s->near_filter[j]*s->near_buf[p];
+        if (++p >= s->near_filter_len)
+            p = 0;
+    }
+    
+    /* Add noise */
+    sum += awgn(&s->near_noise);
+    
+    return sum;
+}
+/*- End of function --------------------------------------------------------*/
+
+static float calc_far_line_filter(one_way_line_model_state_t *s, float v)
+{
+    float sum;
+    int j;
+    int p;
+
+    /* Add the sample in the filter buffer */
+    p = s->far_buf_ptr;
+    s->far_buf[p] = v;
+    if (++p == s->far_filter_len)
+        p = 0;
+    s->far_buf_ptr = p;
+    
+    /* Apply the filter */
+    sum = 0.0f;
+    for (j = 0;  j < s->far_filter_len;  j++)
+    {
+        sum += s->far_filter[j]*s->far_buf[p];
+        if (++p >= s->far_filter_len)
+            p = 0;
+    }
+    
+    /* Add noise */
+    sum += awgn(&s->far_noise);
+
+    return sum;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(void) one_way_line_model(one_way_line_model_state_t *s, 
+                                      int16_t output[],
+                                      const int16_t input[],
+                                      int samples)
+{
+    int i;
+    float in;
+    float out;
+    float out1;
+    int16_t amp[1];
+
+    /* The path being modelled is:
+        terminal
+          | < hybrid
+          |
+          | < noise and filtering
+          |
+          | < hybrid
+         CO
+          |
+          | < A-law distortion + bulk delay
+          |
+         CO
+          | < hybrid
+          |
+          | < noise and filtering
+          |
+          | < hybrid
+        terminal
+     */
+    for (i = 0;  i < samples;  i++)
+    {
+        in = input[i];
+
+        /* Near end analogue section */
+        
+        /* Line model filters & noise */
+        out = calc_near_line_filter(s, in);
+    
+        /* Long distance digital section */
+
+        amp[0] = out;
+        codec_munge(s->munge, amp, 1);
+        out = amp[0];
+        /* Introduce the bulk delay of the long distance link. */
+        out1 = s->bulk_delay_buf[s->bulk_delay_ptr];
+        s->bulk_delay_buf[s->bulk_delay_ptr] = out;
+        out = out1;
+        if (++s->bulk_delay_ptr >= s->bulk_delay)
+            s->bulk_delay_ptr = 0;
+
+        /* Far end analogue section */
+        
+        /* Line model filters & noise */
+        out = calc_far_line_filter(s, out);
+    
+        if (s->mains_interference)
+        {
+            tone_gen(&s->mains_tone, amp, 1);
+            out += amp[0];
+        }
+        output[i] = out + s->dc_offset;
+    }
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(void) one_way_line_model_set_dc(one_way_line_model_state_t *s, float dc)
+{
+    s->dc_offset = dc;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(void) one_way_line_model_set_mains_pickup(one_way_line_model_state_t *s, int f, float level)
+{
+    tone_gen_descriptor_t mains_tone_desc;
+
+    if (f)
+    {
+        make_tone_gen_descriptor(&mains_tone_desc, f, (int) (level - 10.0f), f*3, (int) level, 1, 0, 0, 0, TRUE);
+        tone_gen_init(&s->mains_tone, &mains_tone_desc);
+    }
+    s->mains_interference = f;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(void) both_ways_line_model(both_ways_line_model_state_t *s, 
+                                        int16_t output1[],
+                                        const int16_t input1[],
+                                        int16_t output2[],
+                                        const int16_t input2[],
+                                        int samples)
+{
+    int i;
+    float in1;
+    float in2;
+    float out1;
+    float out2;
+    float tmp1;
+    float tmp2;
+    int16_t amp[1];
+
+    /* The path being modelled is:
+        terminal
+          | < hybrid echo
+          |
+          | < noise and filtering
+          |
+          | < hybrid echo
+         CO
+          |
+          | < A-law distortion + bulk delay
+          |
+         CO
+          | < hybrid echo
+          |
+          | < noise and filtering
+          |
+          | < hybrid echo
+        terminal
+     */
+    for (i = 0;  i < samples;  i++)
+    {
+        in1 = input1[i];
+        in2 = input2[i];
+
+        /* Near end analogue sections */
+        /* Echo from each terminal's CO hybrid */
+        tmp1 = in1 + s->fout2*s->line1.near_co_hybrid_echo;
+        tmp2 = in2 + s->fout1*s->line2.near_co_hybrid_echo;
+
+        /* Line model filters & noise */
+        s->fout1 = calc_near_line_filter(&s->line1, tmp1);
+        s->fout2 = calc_near_line_filter(&s->line2, tmp2);
+
+        /* Long distance digital section */
+
+        /* Introduce distortion due to A-law or u-law munging. */
+        amp[0] = s->fout1;
+        codec_munge(s->line1.munge, amp, 1);
+        s->fout1 = amp[0];
+
+        amp[0] = s->fout2;
+        codec_munge(s->line2.munge, amp, 1);
+        s->fout2 = amp[0];
+
+        /* Introduce the bulk delay of the long distance digital link. */
+        out1 = s->line1.bulk_delay_buf[s->line1.bulk_delay_ptr];
+        s->line1.bulk_delay_buf[s->line1.bulk_delay_ptr] = s->fout1;
+        s->fout1 = out1;
+        if (++s->line1.bulk_delay_ptr >= s->line1.bulk_delay)
+            s->line1.bulk_delay_ptr = 0;
+
+        out2 = s->line2.bulk_delay_buf[s->line2.bulk_delay_ptr];
+        s->line2.bulk_delay_buf[s->line2.bulk_delay_ptr] = s->fout2;
+        s->fout2 = out2;
+        if (++s->line2.bulk_delay_ptr >= s->line2.bulk_delay)
+            s->line2.bulk_delay_ptr = 0;
+
+        /* Far end analogue sections */
+
+        /* Echo from each terminal's own hybrid */
+        out1 += in2*s->line1.far_cpe_hybrid_echo;
+        out2 += in1*s->line2.far_cpe_hybrid_echo;
+
+        /* Line model filters & noise */
+        out1 = calc_far_line_filter(&s->line1, out1);
+        out2 = calc_far_line_filter(&s->line2, out2);
+
+        output1[i] = fsaturate(out1 + s->line1.dc_offset);
+        output2[i] = fsaturate(out2 + s->line2.dc_offset);
+    }
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(void) both_ways_line_model_set_dc(both_ways_line_model_state_t *s, float dc1, float dc2)
+{
+    s->line1.dc_offset = dc1;
+    s->line2.dc_offset = dc2;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(void) both_ways_line_model_set_mains_pickup(both_ways_line_model_state_t *s, int f, float level1, float level2)
+{
+    tone_gen_descriptor_t mains_tone_desc;
+
+    if (f)
+    {
+        make_tone_gen_descriptor(&mains_tone_desc, f, (int) (level1 - 10.0f), f*3, (int) level1, 1, 0, 0, 0, TRUE);
+        tone_gen_init(&s->line1.mains_tone, &mains_tone_desc);
+        make_tone_gen_descriptor(&mains_tone_desc, f, (int) (level2 - 10.0f), f*3, (int) level2, 1, 0, 0, 0, TRUE);
+        tone_gen_init(&s->line2.mains_tone, &mains_tone_desc);
+    }
+    s->line1.mains_interference = f;
+    s->line2.mains_interference = f;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(one_way_line_model_state_t *) one_way_line_model_init(int model, float noise, int codec, int rbs_pattern)
+{
+    one_way_line_model_state_t *s;
+
+    if ((s = (one_way_line_model_state_t *) malloc(sizeof(*s))) == NULL)
+        return NULL;
+    memset(s, 0, sizeof(*s));
+
+    s->bulk_delay = 8;
+    s->bulk_delay_ptr = 0;
+
+    s->munge = codec_munge_init(codec, rbs_pattern);
+
+    s->near_filter = line_models[model];
+    s->near_filter_len = 129;
+
+    s->far_filter = line_models[model];
+    s->far_filter_len = 129;
+
+    /* Put half the noise in each analogue section */
+    awgn_init_dbm0(&s->near_noise, 1234567, noise - 3.02f);
+    awgn_init_dbm0(&s->far_noise, 1234567, noise - 3.02f);
+    
+    s->dc_offset = 0.0f;
+    s->mains_interference = 0;
+
+    return s;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) one_way_line_model_release(one_way_line_model_state_t *s)
+{
+    free(s);
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(both_ways_line_model_state_t *) both_ways_line_model_init(int model1,
+                                                                       float noise1,
+                                                                       int model2,
+                                                                       float noise2,
+                                                                       int codec,
+                                                                       int rbs_pattern)
+{
+    float echo_level;
+    both_ways_line_model_state_t *s;
+
+    if ((s = (both_ways_line_model_state_t *) malloc(sizeof(*s))) == NULL)
+        return NULL;
+    memset(s, 0, sizeof(*s));
+
+    s->line1.munge = codec_munge_init(codec, rbs_pattern);
+    s->line2.munge = codec_munge_init(codec, rbs_pattern);
+
+    s->line1.bulk_delay = 8;
+    s->line2.bulk_delay = 8;
+
+    s->line1.bulk_delay_ptr = 0;
+    s->line2.bulk_delay_ptr = 0;
+
+    s->line1.near_filter = line_models[model1];
+    s->line1.near_filter_len = 129;
+    s->line2.near_filter = line_models[model2];
+    s->line2.near_filter_len = 129;
+
+    s->line1.far_filter = line_models[model1];
+    s->line1.far_filter_len = 129;
+    s->line2.far_filter = line_models[model2];
+    s->line2.far_filter_len = 129;
+
+    /* Put half the noise in each analogue section */
+    awgn_init_dbm0(&s->line1.near_noise, 1234567, noise1 - 3.02f);
+    awgn_init_dbm0(&s->line2.near_noise, 7654321, noise2 - 3.02f);
+
+    awgn_init_dbm0(&s->line1.far_noise, 1234567, noise1 - 3.02f);
+    awgn_init_dbm0(&s->line2.far_noise, 7654321, noise2 - 3.02f);
+
+    s->line1.dc_offset = 0.0f;
+    s->line2.dc_offset = 0.0f;
+    s->line1.mains_interference = 0;
+    s->line2.mains_interference = 0;
+
+    /* Echos */
+    echo_level = -15; /* in dB */
+    s->line1.near_co_hybrid_echo = pow(10, echo_level/20.0f);
+    s->line2.near_co_hybrid_echo = pow(10, echo_level/20.0f);
+    s->line1.near_cpe_hybrid_echo = pow(10, echo_level/20.0f);
+    s->line2.near_cpe_hybrid_echo = pow(10, echo_level/20.0f);
+    
+    return s;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) both_ways_line_model_release(both_ways_line_model_state_t *s)
+{
+    free(s);
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/