--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/make_modem_filter.c	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,475 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * make_modem_filter.c - Create coefficient sets for pulse shaping
+ *                       various modem rx and tx signals.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2008 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: make_modem_filter.c,v 1.17.4.1 2009/12/28 12:20:46 steveu Exp $
+ */
+
+#if defined(HAVE_CONFIG_H)
+#include "config.h"
+#endif
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <unistd.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#include <math.h>
+#endif
+#include "floating_fudge.h"
+#include <string.h>
+#include <stdio.h>
+#include <time.h>
+#include <fcntl.h>
+#if defined(__sunos)  ||  defined(__solaris)  ||  defined(__sun)
+#include <getopt.h>
+#endif
+
+#include "spandsp/telephony.h"
+#include "spandsp/complex.h"
+#include "filter_tools.h"
+
+#if !defined(FALSE)
+#define FALSE 0
+#endif
+#if !defined(TRUE)
+#define TRUE (!FALSE)
+#endif
+
+//#define SAMPLE_RATE         8000.0
+#define MAX_COEFFS_PER_FILTER   128
+#define MAX_COEFF_SETS          384
+
+static void make_tx_filter(int coeff_sets,
+                           int coeffs_per_filter,
+                           double carrier,
+                           double baud_rate,
+                           double excess_bandwidth,
+                           int fixed_point,
+                           const char *tag)
+{
+    int i;
+    int j;
+    int x;
+    int total_coeffs;
+    double alpha;
+    double beta;
+    double gain;
+    double scaling;
+    double peak;
+    double coeffs[MAX_COEFF_SETS*MAX_COEFFS_PER_FILTER + 1];
+
+    total_coeffs = coeff_sets*coeffs_per_filter + 1;
+    alpha = baud_rate/(2.0*(double) (coeff_sets*baud_rate));
+    beta = excess_bandwidth;
+
+    compute_raised_cosine_filter(coeffs, total_coeffs, TRUE, FALSE, alpha, beta);
+
+    /* Find the DC gain of the filter, and adjust the filter to unity gain. */
+    gain = 0.0;
+    for (i = coeff_sets/2;  i < total_coeffs;  i += coeff_sets)
+        gain += coeffs[i];
+    /* Normalise the gain to 1.0 */
+    for (i = 0;  i < total_coeffs;  i++)
+        coeffs[i] /= gain;
+    gain = 1.0;
+
+    if (fixed_point)
+    {
+        peak = -1.0;
+        for (i = 0;  i < total_coeffs;  i++)
+        {
+            if (fabs(coeffs[i]) > peak)
+                peak = fabs(coeffs[i]);
+        }
+        scaling = 32767.0;
+        if (peak >= 1.0)
+        {
+            scaling /= peak;
+            gain = 1.0/peak;
+        }
+        for (i = 0;  i < total_coeffs;  i++)
+            coeffs[i] *= scaling;
+    }
+    
+    /* Churn out the data as a C source code header file, which can be directly included by the
+       modem code. */
+    printf("#define TX_PULSESHAPER%s_GAIN        %ff\n", tag, gain);
+    printf("#define TX_PULSESHAPER%s_COEFF_SETS  %d\n", tag, coeff_sets);
+    printf("static const %s tx_pulseshaper%s[TX_PULSESHAPER%s_COEFF_SETS][%d] =\n",
+           (fixed_point)  ?  "int16_t"  :  "float",
+           tag,
+           tag,
+           coeffs_per_filter);
+    printf("{\n");
+    for (j = 0;  j < coeff_sets;  j++)
+    {
+        x = j;
+        printf("    {\n");
+        if (fixed_point)
+            printf("        %8d,     /* Filter %d */\n", (int) coeffs[x], j);
+        else
+            printf("        %15.10ff,     /* Filter %d */\n", coeffs[x], j);
+        for (i = 1;  i < coeffs_per_filter - 1;  i++)
+        {
+            x = i*coeff_sets + j;
+            if (fixed_point)
+                printf("        %8d,\n", (int) coeffs[x]);
+            else
+                printf("        %15.10ff,\n", coeffs[x]);
+        }
+        x = i*coeff_sets + j;
+        if (fixed_point)
+            printf("        %8d\n", (int) coeffs[x]);
+        else
+            printf("        %15.10ff\n", coeffs[x]);
+        if (j < coeff_sets - 1)
+            printf("    },\n");
+        else
+            printf("    }\n");
+    }
+    printf("};\n");
+}
+/*- End of function --------------------------------------------------------*/
+
+static void make_rx_filter(int coeff_sets,
+                           int coeffs_per_filter,
+                           double carrier,
+                           double baud_rate,
+                           double excess_bandwidth,
+                           int fixed_point,
+                           const char *tag)
+{
+    int i;
+    int j;
+    int k;
+    int m;
+    int x;
+    int total_coeffs;
+    double alpha;
+    double beta;
+    double gain;
+    double peak;
+    double coeffs[MAX_COEFF_SETS*MAX_COEFFS_PER_FILTER + 1];
+#if 0
+    complex_t co[MAX_COEFFS_PER_FILTER];
+#else
+    double cox[MAX_COEFFS_PER_FILTER];
+#endif
+
+    total_coeffs = coeff_sets*coeffs_per_filter + 1;
+    alpha = baud_rate/(2.0*(double) (coeff_sets*SAMPLE_RATE));
+    beta = excess_bandwidth;
+    carrier *= 2.0*3.1415926535/SAMPLE_RATE;
+
+    compute_raised_cosine_filter(coeffs, total_coeffs, TRUE, FALSE, alpha, beta);
+
+    /* Find the DC gain of the filter, and adjust the filter to unity gain. */
+    gain = 0.0;
+    for (i = coeff_sets/2;  i < total_coeffs;  i += coeff_sets)
+        gain += coeffs[i];
+    /* Normalise the gain to 1.0 */
+    for (i = 0;  i < total_coeffs;  i++)
+        coeffs[i] /= gain;
+    gain = 1.0;
+
+    if (fixed_point)
+    {
+        peak = -1.0;
+        for (i = 0;  i < total_coeffs;  i++)
+        {
+            if (fabs(coeffs[i]) > peak)
+                peak = fabs(coeffs[i]);
+        }
+        gain = 32767.0;
+        if (peak >= 1.0)
+            gain /= peak;
+        for (i = 0;  i < total_coeffs;  i++)
+            coeffs[i] *= gain;
+    }
+
+    /* Churn out the data as a C source code header file, which can be directly included by the
+       modem code. */
+    printf("#define RX_PULSESHAPER%s_GAIN        %ff\n", tag, gain);
+    printf("#define RX_PULSESHAPER%s_COEFF_SETS  %d\n", tag, coeff_sets);
+#if 0
+    printf("static const %s rx_pulseshaper%s[RX_PULSESHAPER%s_COEFF_SETS][%d] =\n",
+           (fixed_point)  ?  "complexi16_t"  :  "complexf_t",
+           tag,
+           tag,
+           coeffs_per_filter);
+    printf("{\n");
+    for (j = 0;  j < coeff_sets;  j++)
+    {
+        /* Complex modulate the filter, to make it a complex pulse shaping bandpass filter
+           centred at the nominal carrier frequency. Use the same phase for all the coefficient
+           sets. This means the modem can step the carrier in whole samples, and not worry about
+           the fractional sample shift caused by selecting amongst the various coefficient sets. */
+        for (i = 0;  i < coeffs_per_filter;  i++)
+        {
+            m = i - (coeffs_per_filter >> 1);
+            x = i*coeff_sets + j;
+            co[i].re = coeffs[x]*cos(carrier*m);
+            co[i].im = coeffs[x]*sin(carrier*m);
+        }
+        printf("    {\n");
+        if (fixed_point)
+            printf("        {%8d, %8d},     /* Filter %d */\n", (int) co[i].re, (int) co[i].im, j);
+        else
+            printf("        {%15.10ff, %15.10ff},     /* Filter %d */\n", co[0].re, co[0].im, j);
+        for (i = 1;  i < coeffs_per_filter - 1;  i++)
+        {
+            if (fixed_point)
+                printf("        {%8d, %8d},\n", (int) co[i].re, (int) co[i].im);
+            else
+                printf("        {%15.10ff, %15.10ff},\n", co[i].re, co[i].im);
+        }
+        if (fixed_point)
+            printf("        {%8d, %8d}\n", (int) co[i].re, (int) co[i].im);
+        else
+            printf("        {%15.10ff, %15.10ff}\n", co[i].re, co[i].im);
+        if (j < coeff_sets - 1)
+            printf("    },\n");
+        else
+            printf("    }\n");
+    }
+    printf("};\n");
+#else
+    for (k = 0;  k < 2;  k++)
+    {
+        printf("static const %s rx_pulseshaper%s_%s[RX_PULSESHAPER%s_COEFF_SETS][%d] =\n",
+               (fixed_point)  ?  "int16_t"  :  "float",
+               tag,
+               (k == 0)  ?  "re"  :  "im",
+               tag,
+               coeffs_per_filter);
+        printf("{\n");
+        for (j = 0;  j < coeff_sets;  j++)
+        {
+            /* Complex modulate the filter, to make it a complex pulse shaping bandpass filter
+               centred at the nominal carrier frequency. Use the same phase for all the coefficient
+               sets. This means the modem can step the carrier in whole samples, and not worry about
+               the fractional sample shift caused by selecting amongst the various coefficient sets. */
+            for (i = 0;  i < coeffs_per_filter;  i++)
+            {
+                m = i - (coeffs_per_filter >> 1);
+                x = i*coeff_sets + j;
+                if (k == 0)
+                    cox[i] = coeffs[x]*cos(carrier*m);
+                else
+                    cox[i] = coeffs[x]*sin(carrier*m);
+            }
+            printf("    {\n");
+            if (fixed_point)
+                printf("        %8d,     /* Filter %d */\n", (int) cox[0], j);
+            else
+                printf("        %15.10ff,     /* Filter %d */\n", cox[0], j);
+            for (i = 1;  i < coeffs_per_filter - 1;  i++)
+            {
+                if (fixed_point)
+                    printf("        %8d,\n", (int) cox[i]);
+                else
+                    printf("        %15.10ff,\n", cox[i]);
+            }
+            if (fixed_point)
+                printf("        %8d\n", (int) cox[i]);
+            else
+                printf("        %15.10ff\n", cox[i]);
+            if (j < coeff_sets - 1)
+                printf("    },\n");
+            else
+                printf("    }\n");
+        }
+        printf("};\n");
+    }
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+static void usage(void)
+{
+    fprintf(stderr, "Usage: make_modem_rx_filter -m <V.17 | V.22bis | V.22bis1200 | V.22bis2400 | V.27ter2400 | V.27ter4800 | V.29> [-i] [-r] [-t]\n");
+}
+/*- End of function --------------------------------------------------------*/
+
+int main(int argc, char **argv)
+{
+    int rx_coeff_sets;
+    int rx_coeffs_per_filter;
+    int tx_coeff_sets;
+    int tx_coeffs_per_filter;
+    int opt;
+    int transmit_modem;
+    int fixed_point;
+    double carrier;
+    double baud_rate;
+    double rx_excess_bandwidth;
+    double tx_excess_bandwidth;
+    const char *tag;
+    const char *modem;
+
+    fixed_point = FALSE;
+    transmit_modem = FALSE;
+    modem = "";
+    while ((opt = getopt(argc, argv, "im:rt")) != -1)
+    {
+        switch (opt)
+        {
+        case 'i':
+            fixed_point = TRUE;
+            break;
+        case 'm':
+            modem = optarg;
+            break;
+        case 'r':
+            transmit_modem = FALSE;
+            break;
+        case 't':
+            transmit_modem = TRUE;
+            break;
+        default:
+            usage();
+            exit(2);
+            break;
+        }
+    }
+    if (strcmp(modem, "V.17") == 0  ||  strcmp(modem, "V.32bis") == 0)
+    {
+        /* This applies to V.32bis as well as V.17 */
+        rx_coeff_sets = 192;
+        rx_coeffs_per_filter = 27;
+        rx_excess_bandwidth = 0.5;
+        tx_coeff_sets = 10;
+        tx_coeffs_per_filter = 9;
+        tx_excess_bandwidth = 0.25;
+        carrier = 1800.0;
+        baud_rate = 2400.0;
+        tag = "";
+    }
+    else if (strcmp(modem, "V.22bis") == 0)
+    {
+        /* This is only intended to apply to transmit. */
+        rx_coeff_sets = 12;
+        rx_coeffs_per_filter = 37;
+        rx_excess_bandwidth = 0.75;
+        tx_coeff_sets = 40;
+        tx_coeffs_per_filter = 9;
+        tx_excess_bandwidth = 0.75;
+        carrier = 1200.0;
+        baud_rate = 600.0;
+        tag = "";
+    }
+    else if (strcmp(modem, "V.22bis1200") == 0)
+    {
+        /* This is only intended to apply to receive. */
+        rx_coeff_sets = 12;
+        rx_coeffs_per_filter = 37;
+        rx_excess_bandwidth = 0.75;
+        tx_coeff_sets = 40;
+        tx_coeffs_per_filter = 9;
+        tx_excess_bandwidth = 0.75;
+        carrier = 1200.0;
+        baud_rate = 600.0;
+        tag = "_1200";
+    }
+    else if (strcmp(modem, "V.22bis2400") == 0)
+    {
+        /* This is only intended to apply to receive. */
+        rx_coeff_sets = 12;
+        rx_coeffs_per_filter = 37;
+        rx_excess_bandwidth = 0.75;
+        tx_coeff_sets = 40;
+        tx_coeffs_per_filter = 9;
+        tx_excess_bandwidth = 0.75;
+        carrier = 2400.0;
+        baud_rate = 600.0;
+        tag = "_2400";
+    }
+    else if (strcmp(modem, "V.27ter4800") == 0)
+    {
+        rx_coeff_sets = 8;
+        rx_coeffs_per_filter = 27;
+        rx_excess_bandwidth = 0.5;
+        tx_coeff_sets = 5;
+        tx_coeffs_per_filter = 9;
+        tx_excess_bandwidth = 0.5;
+        carrier = 1800.0;
+        baud_rate = 1600.0;
+        tag = "_4800";
+    }
+    else if (strcmp(modem, "V.27ter2400") == 0)
+    {
+        rx_coeff_sets = 12;
+        rx_coeffs_per_filter = 27;
+        rx_excess_bandwidth = 0.5;
+        tx_coeff_sets = 20;
+        tx_coeffs_per_filter = 9;
+        tx_excess_bandwidth = 0.5;
+        carrier = 1800.0;
+        baud_rate = 1200.0;
+        tag = "_2400";
+    }
+    else if (strcmp(modem, "V.29") == 0)
+    {
+        rx_coeff_sets = 48;
+        rx_coeffs_per_filter = 27;
+        rx_excess_bandwidth = 0.5;
+        tx_coeff_sets = 10;
+        tx_coeffs_per_filter = 9;
+        tx_excess_bandwidth = 0.25;
+        carrier = 1700.0;
+        baud_rate = 2400.0;
+        tag = "";
+    }
+    else
+    {
+        usage();
+        exit(2);
+    }
+    if (transmit_modem)
+    {
+        make_tx_filter(tx_coeff_sets,
+                       tx_coeffs_per_filter,
+                       carrier,
+                       baud_rate,
+                       tx_excess_bandwidth,
+                       fixed_point,
+                       tag);
+    }
+    else
+    {
+        make_rx_filter(rx_coeff_sets,
+                       rx_coeffs_per_filter,
+                       carrier,
+                       baud_rate,
+                       rx_excess_bandwidth,
+                       fixed_point,
+                       tag);
+    }
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/