570 lines
17 KiB
C
570 lines
17 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* make_modem_filter.c - Create coefficient sets for pulse shaping
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* various modem rx and tx signals.
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2008 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <inttypes.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdio.h>
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#include <time.h>
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#include <fcntl.h>
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#include <math.h>
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#if defined(HAVE_STDBOOL_H)
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#include <stdbool.h>
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#else
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#include "spandsp/stdbool.h"
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#endif
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#if defined(__sunos) || defined(__solaris) || defined(__sun)
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#include <getopt.h>
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#endif
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#if defined (_MSC_VER)
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#define __inline__ __inline
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#endif
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#include "spandsp/telephony.h"
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#include "spandsp/complex.h"
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#include "filter_tools.h"
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//#define SAMPLE_RATE 8000.0
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#define MAX_COEFFS_PER_FILTER 128
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#define MAX_COEFF_SETS 384
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static void make_tx_filter(int coeff_sets,
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int coeffs_per_filter,
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double carrier,
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double baud_rate,
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double excess_bandwidth,
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const char *tag)
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{
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int i;
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int j;
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int x;
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int total_coeffs;
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double alpha;
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double beta;
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double floating_gain;
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double fixed_gain;
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double fixed_scaling;
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double peak;
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double coeffs[MAX_COEFF_SETS*MAX_COEFFS_PER_FILTER + 1];
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total_coeffs = coeff_sets*coeffs_per_filter + 1;
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alpha = baud_rate/(2.0*(double) (coeff_sets*baud_rate));
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beta = excess_bandwidth;
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compute_raised_cosine_filter(coeffs, total_coeffs, true, false, alpha, beta);
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/* Find the DC gain of the filter, and adjust the filter to unity gain. */
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floating_gain = 0.0;
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for (i = coeff_sets/2; i < total_coeffs; i += coeff_sets)
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floating_gain += coeffs[i];
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/* Normalise the gain to 1.0 */
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for (i = 0; i < total_coeffs; i++)
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coeffs[i] /= floating_gain;
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floating_gain = 1.0;
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fixed_gain = 1.0;
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peak = -1.0;
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for (i = 0; i < total_coeffs; i++)
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{
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if (fabs(coeffs[i]) > peak)
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peak = fabs(coeffs[i]);
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}
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fixed_scaling = 32767.0f;
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if (peak >= 1.0)
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{
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fixed_scaling /= peak;
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fixed_gain = 1.0/peak;
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}
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/* Churn out the data as a C source code header file, which can be directly included by the
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modem code. */
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printf("/* THIS FILE WAS AUTOMATICALLY GENERATED - ANY MODIFICATIONS MADE TO THIS");
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printf(" FILE MAY BE OVERWRITTEN DURING FUTURE BUILDS OF THE SOFTWARE */\n");
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printf("\n");
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printf("#if defined(SPANDSP_USE_FIXED_POINT)\n");
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printf("#define TX_PULSESHAPER%s_SCALE(x) ((int16_t) (%f*x + ((x >= 0.0) ? 0.5 : -0.5)))\n", tag, fixed_scaling);
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printf("#define TX_PULSESHAPER%s_GAIN %ff\n", tag, fixed_gain);
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printf("#else\n");
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printf("#define TX_PULSESHAPER%s_SCALE(x) (x)\n", tag);
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printf("#define TX_PULSESHAPER%s_GAIN %ff\n", tag, floating_gain);
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printf("#endif\n");
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printf("#define TX_PULSESHAPER%s_COEFF_SETS %d\n", tag, coeff_sets);
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printf("\n");
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printf("#if defined(SPANDSP_USE_FIXED_POINT)\n");
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printf("static const int16_t tx_pulseshaper%s[TX_PULSESHAPER%s_COEFF_SETS][%d] =\n",
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tag,
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tag,
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coeffs_per_filter);
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printf("#else\n");
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printf("static const float tx_pulseshaper%s[TX_PULSESHAPER%s_COEFF_SETS][%d] =\n",
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tag,
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tag,
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coeffs_per_filter);
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printf("#endif\n");
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printf("{\n");
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for (j = 0; j < coeff_sets; j++)
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{
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x = j;
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printf(" {\n");
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printf(" TX_PULSESHAPER%s_SCALE(%15.10ff), /* Filter %d */\n", tag, coeffs[x], j);
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for (i = 1; i < coeffs_per_filter - 1; i++)
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{
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x = i*coeff_sets + j;
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printf(" TX_PULSESHAPER%s_SCALE(%15.10ff),\n", tag, coeffs[x]);
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}
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x = i*coeff_sets + j;
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printf(" TX_PULSESHAPER%s_SCALE(%15.10ff)\n", tag, coeffs[x]);
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if (j < coeff_sets - 1)
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printf(" },\n");
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else
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printf(" }\n");
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}
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printf("};\n");
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}
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/*- End of function --------------------------------------------------------*/
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static void make_rx_filter(int coeff_sets,
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int coeffs_per_filter,
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double carrier,
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double baud_rate,
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double excess_bandwidth,
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const char *tag)
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{
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int i;
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int j;
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int k;
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int m;
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int x;
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int total_coeffs;
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double alpha;
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double beta;
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double floating_gain;
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double fixed_gain;
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double fixed_scaling;
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double peak;
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double coeffs[MAX_COEFF_SETS*MAX_COEFFS_PER_FILTER + 1];
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double cox[MAX_COEFFS_PER_FILTER];
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total_coeffs = coeff_sets*coeffs_per_filter + 1;
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alpha = baud_rate/(2.0*(double) (coeff_sets*SAMPLE_RATE));
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beta = excess_bandwidth;
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carrier *= 2.0*3.1415926535/SAMPLE_RATE;
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compute_raised_cosine_filter(coeffs, total_coeffs, true, false, alpha, beta);
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/* Find the DC gain of the filter, and adjust the filter to unity gain. */
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floating_gain = 0.0;
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for (i = coeff_sets/2; i < total_coeffs; i += coeff_sets)
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floating_gain += coeffs[i];
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/* Normalise the gain to 1.0 */
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for (i = 0; i < total_coeffs; i++)
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coeffs[i] /= floating_gain;
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floating_gain = 1.0;
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fixed_gain = 1.0;
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peak = -1.0;
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for (i = 0; i < total_coeffs; i++)
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{
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if (fabs(coeffs[i]) > peak)
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peak = fabs(coeffs[i]);
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}
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fixed_scaling = 32767.0f;
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if (peak >= 1.0)
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{
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fixed_scaling /= peak;
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fixed_gain = 1.0/peak;
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}
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/* Churn out the data as a C source code header file, which can be directly included by the
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modem code. */
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printf("#if defined(SPANDSP_USE_FIXED_POINT)\n");
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printf("#define RX_PULSESHAPER%s_SCALE(x) ((int16_t) (%f*x + ((x >= 0.0) ? 0.5 : -0.5)))\n", tag, fixed_scaling);
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printf("#define RX_PULSESHAPER%s_GAIN %ff\n", tag, fixed_gain);
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printf("#else\n");
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printf("#define RX_PULSESHAPER%s_SCALE(x) (x)\n", tag);
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printf("#define RX_PULSESHAPER%s_GAIN %ff\n", tag, floating_gain);
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printf("#endif\n");
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printf("#define RX_PULSESHAPER%s_COEFF_SETS %d\n", tag, coeff_sets);
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for (k = 0; k < 2; k++)
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{
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printf("\n");
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printf("#if defined(SPANDSP_USE_FIXED_POINT)\n");
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printf("static const int16_t rx_pulseshaper%s_%s[RX_PULSESHAPER%s_COEFF_SETS][%d] =\n",
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tag,
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(k == 0) ? "re" : "im",
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tag,
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coeffs_per_filter);
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printf("#else\n");
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printf("static const float rx_pulseshaper%s_%s[RX_PULSESHAPER%s_COEFF_SETS][%d] =\n",
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tag,
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(k == 0) ? "re" : "im",
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tag,
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coeffs_per_filter);
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printf("#endif\n");
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printf("{\n");
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for (j = 0; j < coeff_sets; j++)
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{
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/* Complex modulate the filter, to make it a complex pulse shaping bandpass filter
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centred at the nominal carrier frequency. Use the same phase for all the coefficient
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sets. This means the modem can step the carrier in whole samples, and not worry about
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the fractional sample shift caused by selecting amongst the various coefficient sets. */
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for (i = 0; i < coeffs_per_filter; i++)
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{
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m = i - (coeffs_per_filter >> 1);
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x = i*coeff_sets + j;
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if (k == 0)
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cox[i] = coeffs[x]*cos(carrier*m);
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else
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cox[i] = coeffs[x]*sin(carrier*m);
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}
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printf(" {\n");
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printf(" RX_PULSESHAPER%s_SCALE(%15.10ff), /* Filter %d */\n", tag, cox[0], j);
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for (i = 1; i < coeffs_per_filter - 1; i++)
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printf(" RX_PULSESHAPER%s_SCALE(%15.10ff),\n", tag, cox[i]);
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printf(" RX_PULSESHAPER%s_SCALE(%15.10ff)\n", tag, cox[i]);
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if (j < coeff_sets - 1)
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printf(" },\n");
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else
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printf(" }\n");
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}
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printf("};\n");
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}
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}
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/*- End of function --------------------------------------------------------*/
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static void usage(void)
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{
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fprintf(stderr, "Usage: make_modem_rx_filter -m <V.17 | V.22bis | V.22bis1200 | V.22bis2400 | V.27ter2400 | V.27ter4800 | V.29> [-r] [-t]\n");
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}
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/*- End of function --------------------------------------------------------*/
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int main(int argc, char **argv)
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{
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int rx_coeff_sets;
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int rx_coeffs_per_filter;
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int tx_coeff_sets;
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int tx_coeffs_per_filter;
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int opt;
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int transmit_modem;
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double carrier;
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double baud_rate;
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double rx_excess_bandwidth;
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double tx_excess_bandwidth;
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const char *rx_tag;
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const char *tx_tag;
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const char *modem;
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transmit_modem = false;
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modem = "";
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while ((opt = getopt(argc, argv, "m:rt")) != -1)
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{
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switch (opt)
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{
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case 'm':
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modem = optarg;
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break;
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case 'r':
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transmit_modem = false;
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break;
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case 't':
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transmit_modem = true;
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break;
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default:
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usage();
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exit(2);
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break;
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}
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}
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if (strcmp(modem, "V.17") == 0 || strcmp(modem, "V.32bis") == 0)
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{
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/* This applies to V.32bis as well as V.17 */
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rx_coeff_sets = 192;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.5;
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tx_coeff_sets = 10;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.25;
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carrier = 1800.0;
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baud_rate = 2400.0;
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rx_tag = "";
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tx_tag = "";
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}
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else if (strcmp(modem, "V.22bis") == 0)
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{
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/* This is only intended to apply to transmit. */
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rx_coeff_sets = 12;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.75;
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tx_coeff_sets = 40;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.75;
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carrier = 1200.0;
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baud_rate = 600.0;
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rx_tag = "";
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tx_tag = "";
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}
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else if (strcmp(modem, "V.22bis1200") == 0)
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{
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/* This is only intended to apply to receive. */
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rx_coeff_sets = 12;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.75;
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tx_coeff_sets = 40;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.75;
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carrier = 1200.0;
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baud_rate = 600.0;
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rx_tag = "_1200";
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tx_tag = "_1200";
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}
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else if (strcmp(modem, "V.22bis2400") == 0)
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{
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/* This is only intended to apply to receive. */
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rx_coeff_sets = 12;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.75;
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tx_coeff_sets = 40;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.75;
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carrier = 2400.0;
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baud_rate = 600.0;
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rx_tag = "_2400";
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tx_tag = "_2400";
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}
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else if (strcmp(modem, "V.27ter2400") == 0)
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{
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rx_coeff_sets = 12;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.5;
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tx_coeff_sets = 20;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.5;
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carrier = 1800.0;
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baud_rate = 1200.0;
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rx_tag = "_2400";
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tx_tag = "_2400";
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}
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else if (strcmp(modem, "V.27ter4800") == 0)
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{
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rx_coeff_sets = 8;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.5;
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tx_coeff_sets = 5;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.5;
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carrier = 1800.0;
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baud_rate = 1600.0;
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rx_tag = "_4800";
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tx_tag = "_4800";
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}
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else if (strcmp(modem, "V.29") == 0)
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{
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rx_coeff_sets = 48;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.5;
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tx_coeff_sets = 10;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.25;
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carrier = 1700.0;
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baud_rate = 2400.0;
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rx_tag = "";
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tx_tag = "";
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}
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else if (strcmp(modem, "V.34_2400") == 0)
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{
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rx_coeff_sets = 192;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.25;
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tx_coeff_sets = 10;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.12;
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carrier = 1600.0;
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baud_rate = 2400.0;
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rx_tag = "_2400_low_carrier";
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tx_tag = "_2400";
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}
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else if (strcmp(modem, "V.34_2400_high") == 0)
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{
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rx_coeff_sets = 192;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.25;
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tx_coeff_sets = 10;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.12;
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carrier = 1800.0;
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baud_rate = 2400.0;
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rx_tag = "_2400_high_carrier";
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tx_tag = "_2400";
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}
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else if (strcmp(modem, "V.34_2743") == 0)
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{
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rx_coeff_sets = 192;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.25;
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tx_coeff_sets = 35;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.12;
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carrier = 1646.0;
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baud_rate = 2400.0*8.0/7.0;
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rx_tag = "_2743_low_carrier";
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tx_tag = "_2743";
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}
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else if (strcmp(modem, "V.34_2743_high") == 0)
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{
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rx_coeff_sets = 192;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.25;
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tx_coeff_sets = 35;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.12;
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carrier = 1829.0;
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baud_rate = 2400.0*8.0/7.0;
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rx_tag = "_2743_high_carrier";
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tx_tag = "_2743";
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}
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else if (strcmp(modem, "V.34_2800") == 0)
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{
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rx_coeff_sets = 192;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.25;
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tx_coeff_sets = 20;
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tx_coeffs_per_filter = 9;
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tx_excess_bandwidth = 0.12;
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carrier = 1680.0;
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baud_rate = 2400.0*7.0/6.0;
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rx_tag = "_2800_low_carrier";
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tx_tag = "_2800";
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}
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else if (strcmp(modem, "V.34_2800_high") == 0)
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{
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rx_coeff_sets = 192;
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rx_coeffs_per_filter = 27;
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rx_excess_bandwidth = 0.25;
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|
tx_coeff_sets = 20;
|
|
tx_coeffs_per_filter = 9;
|
|
tx_excess_bandwidth = 0.12;
|
|
carrier = 1867.0;
|
|
baud_rate = 2400.0*7.0/6.0;
|
|
rx_tag = "_2800_high_carrier";
|
|
tx_tag = "_2800";
|
|
}
|
|
else if (strcmp(modem, "V.34_3000") == 0)
|
|
{
|
|
rx_coeff_sets = 192;
|
|
rx_coeffs_per_filter = 27;
|
|
rx_excess_bandwidth = 0.25;
|
|
tx_coeff_sets = 8;
|
|
tx_coeffs_per_filter = 9;
|
|
tx_excess_bandwidth = 0.12;
|
|
carrier = 1800.0;
|
|
baud_rate = 2400.0*5.0/4.0;
|
|
rx_tag = "_3000_low_carrier";
|
|
tx_tag = "_3000";
|
|
}
|
|
else if (strcmp(modem, "V.34_3000_high") == 0)
|
|
{
|
|
rx_coeff_sets = 192;
|
|
rx_coeffs_per_filter = 27;
|
|
rx_excess_bandwidth = 0.25;
|
|
tx_coeff_sets = 8;
|
|
tx_coeffs_per_filter = 9;
|
|
tx_excess_bandwidth = 0.12;
|
|
carrier = 2000.0;
|
|
baud_rate = 2400.0*5.0/4.0;
|
|
rx_tag = "_3000_high_carrier";
|
|
tx_tag = "_3000";
|
|
}
|
|
else if (strcmp(modem, "V.34_3200") == 0)
|
|
{
|
|
rx_coeff_sets = 192;
|
|
rx_coeffs_per_filter = 27;
|
|
rx_excess_bandwidth = 0.25;
|
|
tx_coeff_sets = 5;
|
|
tx_coeffs_per_filter = 9;
|
|
tx_excess_bandwidth = 0.12;
|
|
carrier = 1829.0;
|
|
baud_rate = 2400.0*4.0/3.0;
|
|
rx_tag = "_3200_low_carrier";
|
|
tx_tag = "_3200";
|
|
}
|
|
else if (strcmp(modem, "V.34_3200_high") == 0)
|
|
{
|
|
rx_coeff_sets = 192;
|
|
rx_coeffs_per_filter = 27;
|
|
rx_excess_bandwidth = 0.25;
|
|
tx_coeff_sets = 5;
|
|
tx_coeffs_per_filter = 9;
|
|
tx_excess_bandwidth = 0.12;
|
|
carrier = 1920.0;
|
|
baud_rate = 2400.0*4.0/3.0;
|
|
rx_tag = "_3200_high_carrier";
|
|
tx_tag = "_3200";
|
|
}
|
|
else if (strcmp(modem, "V.34_3429") == 0)
|
|
{
|
|
/* There is only one carrier frequency defined for this baud rate */
|
|
rx_coeff_sets = 192;
|
|
rx_coeffs_per_filter = 27;
|
|
rx_excess_bandwidth = 0.25;
|
|
tx_coeff_sets = 7;
|
|
tx_coeffs_per_filter = 9;
|
|
tx_excess_bandwidth = 0.12;
|
|
//carrier = 1959.0;
|
|
carrier = 1959.0;
|
|
baud_rate = 2400.0*10.0/7.0;
|
|
rx_tag = "_3429";
|
|
tx_tag = "_3429";
|
|
}
|
|
else
|
|
{
|
|
usage();
|
|
exit(2);
|
|
}
|
|
if (transmit_modem)
|
|
{
|
|
make_tx_filter(tx_coeff_sets,
|
|
tx_coeffs_per_filter,
|
|
carrier,
|
|
baud_rate,
|
|
tx_excess_bandwidth,
|
|
tx_tag);
|
|
}
|
|
else
|
|
{
|
|
make_rx_filter(rx_coeff_sets,
|
|
rx_coeffs_per_filter,
|
|
carrier,
|
|
baud_rate,
|
|
rx_excess_bandwidth,
|
|
rx_tag);
|
|
}
|
|
return 0;
|
|
}
|
|
/*- End of function --------------------------------------------------------*/
|
|
/*- End of file ------------------------------------------------------------*/
|