audiostuff: spandsp-0.0.6pre17/src/v29tx.c comparison

comparison spandsp-0.0.6pre17/src/v29tx.c @ 4:26cd8f1ef0b1

import spandsp-0.0.6pre17

author	Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date	Fri, 25 Jun 2010 15:50:58 +0200
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-:c6c5a16ce2f2
+:26cd8f1ef0b1
+/*
+* SpanDSP - a series of DSP components for telephony
+*
+* v29tx.c - ITU V.29 modem transmit part
+*
+* Written by Steve Underwood <steveu@coppice.org>
+*
+* Copyright (C) 2003 Steve Underwood
+*
+* All rights reserved.
+*
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU Lesser General Public License version 2.1,
+* 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 Lesser General Public License for more details.
+*
+* You should have received a copy of the GNU Lesser General Public
+* License along with this program; if not, write to the Free Software
+* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*
+* $Id: v29tx.c,v 1.89 2009/06/02 16:03:56 steveu Exp $
+*/
+/*! \file */
+#if defined(HAVE_CONFIG_H)
+#include "config.h"
+#endif
+#include <stdio.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#include <math.h>
+#endif
+#include "floating_fudge.h"
+#include "spandsp/telephony.h"
+#include "spandsp/fast_convert.h"
+#include "spandsp/logging.h"
+#include "spandsp/complex.h"
+#include "spandsp/vector_float.h"
+#include "spandsp/complex_vector_float.h"
+#include "spandsp/async.h"
+#include "spandsp/dds.h"
+#include "spandsp/power_meter.h"
+#include "spandsp/v29tx.h"
+#include "spandsp/private/logging.h"
+#include "spandsp/private/v29tx.h"
+#include "v29tx_constellation_maps.h"
+#if defined(SPANDSP_USE_FIXED_POINT)
+#include "v29tx_fixed_rrc.h"
+#else
+#include "v29tx_floating_rrc.h"
+#endif
+/*! The nominal frequency of the carrier, in Hertz */
+#define CARRIER_NOMINAL_FREQ        1700.0f
+/* Segments of the training sequence */
+/*! The start of the optional TEP, that may preceed the actual training, in symbols */
+#define V29_TRAINING_SEG_TEP        0
+/*! The start of training segment 1, in symbols */
+#define V29_TRAINING_SEG_1          (V29_TRAINING_SEG_TEP + 480)
+/*! The start of training segment 2, in symbols */
+#define V29_TRAINING_SEG_2          (V29_TRAINING_SEG_1 + 48)
+/*! The start of training segment 3, in symbols */
+#define V29_TRAINING_SEG_3          (V29_TRAINING_SEG_2 + 128)
+/*! The start of training segment 4, in symbols */
+#define V29_TRAINING_SEG_4          (V29_TRAINING_SEG_3 + 384)
+/*! The end of the training, in symbols */
+#define V29_TRAINING_END            (V29_TRAINING_SEG_4 + 48)
+/*! The end of the shutdown sequence, in symbols */
+#define V29_TRAINING_SHUTDOWN_END   (V29_TRAINING_END + 32)
+static int fake_get_bit(void *user_data)
+{
+return 1;
+}
+/*- End of function --------------------------------------------------------*/
+static __inline__ int get_scrambled_bit(v29_tx_state_t *s)
+{
+int bit;
+int out_bit;
+if ((bit = s->current_get_bit(s->get_bit_user_data)) == SIG_STATUS_END_OF_DATA)
+{
+/* End of real data. Switch to the fake get_bit routine, until we
+have shut down completely. */
+if (s->status_handler)
+s->status_handler(s->status_user_data, SIG_STATUS_END_OF_DATA);
+s->current_get_bit = fake_get_bit;
+s->in_training = TRUE;
+bit = 1;
+}
+out_bit = (bit ^ (s->scramble_reg >> 17) ^ (s->scramble_reg >> 22)) & 1;
+s->scramble_reg = (s->scramble_reg << 1) | out_bit;
+return out_bit;
+}
+/*- End of function --------------------------------------------------------*/
+#if defined(SPANDSP_USE_FIXED_POINT)
+static __inline__ complexi16_t getbaud(v29_tx_state_t *s)
+#else
+static __inline__ complexf_t getbaud(v29_tx_state_t *s)
+#endif
+{
+static const int phase_steps_9600[8] =
+{
+1, 0, 2, 3, 6, 7, 5, 4
+};
+static const int phase_steps_4800[4] =
+{
+0, 2, 6, 4
+};
+#if defined(SPANDSP_USE_FIXED_POINT)
+static const complexi16_t zero = {0, 0};
+#else
+static const complexf_t zero = {0.0f, 0.0f};
+#endif
+int bits;
+int amp;
+int bit;
+if (s->in_training)
+{
+/* Send the training sequence */
+if (++s->training_step <= V29_TRAINING_SEG_4)
+{
+if (s->training_step <= V29_TRAINING_SEG_3)
+{
+if (s->training_step <= V29_TRAINING_SEG_1)
+{
+/* Optional segment: Unmodulated carrier (talker echo protection) */
+return v29_9600_constellation[0];
+}
+if (s->training_step <= V29_TRAINING_SEG_2)
+{
+/* Segment 1: silence */
+return zero;
+}
+/* Segment 2: ABAB... */
+return v29_abab_constellation[(s->training_step & 1) + s->training_offset];
+}
+/* Segment 3: CDCD... */
+/* Apply the 1 + x^-6 + x^-7 training scrambler */
+bit = s->training_scramble_reg & 1;
+s->training_scramble_reg >>= 1;
+s->training_scramble_reg |= (((bit ^ s->training_scramble_reg) & 1) << 6);
+return v29_cdcd_constellation[bit + s->training_offset];
+}
+/* We should be in the block of test ones, or shutdown ones, if we get here. */
+/* There is no graceful shutdown procedure defined for V.29. Just
+send some ones, to ensure we get the real data bits through, even
+with bad ISI. */
+if (s->training_step == V29_TRAINING_END + 1)
+{
+/* Switch from the fake get_bit routine, to the user supplied real
+one, and we are up and running. */
+s->current_get_bit = s->get_bit;
+s->in_training = FALSE;
+}
+if (s->training_step == V29_TRAINING_SHUTDOWN_END)
+{
+if (s->status_handler)
+s->status_handler(s->status_user_data, SIG_STATUS_SHUTDOWN_COMPLETE);
+}
+}
+/* 9600bps uses the full constellation.
+7200bps uses only the first half of the full constellation.
+4800bps uses the smaller constellation. */
+amp = 0;
+/* We only use an amplitude bit at 9600bps */
+if (s->bit_rate == 9600  &&  get_scrambled_bit(s))
+amp = 8;
+/*endif*/
+bits = get_scrambled_bit(s);
+bits = (bits << 1) | get_scrambled_bit(s);
+if (s->bit_rate == 4800)
+{
+bits = phase_steps_4800[bits];
+}
+else
+{
+bits = (bits << 1) | get_scrambled_bit(s);
+bits = phase_steps_9600[bits];
+}
+s->constellation_state = (s->constellation_state + bits) & 7;
+return v29_9600_constellation[amp | s->constellation_state];
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE_NONSTD(int) v29_tx(v29_tx_state_t *s, int16_t amp[], int len)
+{
+#if defined(SPANDSP_USE_FIXED_POINT)
+complexi_t x;
+complexi_t z;
+#else
+complexf_t x;
+complexf_t z;
+#endif
+int i;
+int sample;
+if (s->training_step >= V29_TRAINING_SHUTDOWN_END)
+{
+/* Once we have sent the shutdown symbols, we stop sending completely. */
+return 0;
+}
+for (sample = 0;  sample < len;  sample++)
+{
+if ((s->baud_phase += 3) >= 10)
+{
+s->baud_phase -= 10;
+s->rrc_filter[s->rrc_filter_step] =
+s->rrc_filter[s->rrc_filter_step + V29_TX_FILTER_STEPS] = getbaud(s);
+if (++s->rrc_filter_step >= V29_TX_FILTER_STEPS)
+s->rrc_filter_step = 0;
+}
+/* Root raised cosine pulse shaping at baseband */
+#if defined(SPANDSP_USE_FIXED_POINT)
+x = complex_seti(0, 0);
+for (i = 0;  i < V29_TX_FILTER_STEPS;  i++)
+{
+x.re += (int32_t) tx_pulseshaper[TX_PULSESHAPER_COEFF_SETS - 1 - s->baud_phase][i]*(int32_t) s->rrc_filter[i + s->rrc_filter_step].re;
+x.im += (int32_t) tx_pulseshaper[TX_PULSESHAPER_COEFF_SETS - 1 - s->baud_phase][i]*(int32_t) s->rrc_filter[i + s->rrc_filter_step].im;
+}
+/* Now create and modulate the carrier */
+x.re >>= 4;
+x.im >>= 4;
+z = dds_complexi(&(s->carrier_phase), s->carrier_phase_rate);
+/* Don't bother saturating. We should never clip. */
+i = (x.re*z.re - x.im*z.im) >> 15;
+amp[sample] = (int16_t) ((i*s->gain) >> 15);
+#else
+x = complex_setf(0.0f, 0.0f);
+for (i = 0;  i < V29_TX_FILTER_STEPS;  i++)
+{
+x.re += tx_pulseshaper[TX_PULSESHAPER_COEFF_SETS - 1 - s->baud_phase][i]*s->rrc_filter[i + s->rrc_filter_step].re;
+x.im += tx_pulseshaper[TX_PULSESHAPER_COEFF_SETS - 1 - s->baud_phase][i]*s->rrc_filter[i + s->rrc_filter_step].im;
+}
+/* Now create and modulate the carrier */
+z = dds_complexf(&(s->carrier_phase), s->carrier_phase_rate);
+/* Don't bother saturating. We should never clip. */
+amp[sample] = (int16_t) lfastrintf((x.re*z.re - x.im*z.im)*s->gain);
+#endif
+}
+return sample;
+}
+/*- End of function --------------------------------------------------------*/
+static void set_working_gain(v29_tx_state_t *s)
+{
+#if defined(SPANDSP_USE_FIXED_POINT)
+switch (s->bit_rate)
+{
+case 9600:
+s->gain = 0.387f*s->base_gain*16.0f*32767.0f/30672.52f;
+break;
+case 7200:
+s->gain = 0.605f*s->base_gain*16.0f*32767.0f/30672.52f;
+break;
+case 4800:
+s->gain = 0.470f*s->base_gain*16.0f*32767.0f/30672.52f;
+break;
+default:
+break;
+}
+#else
+switch (s->bit_rate)
+{
+case 9600:
+s->gain = 0.387f*s->base_gain;
+break;
+case 7200:
+s->gain = 0.605f*s->base_gain;
+break;
+case 4800:
+s->gain = 0.470f*s->base_gain;
+break;
+default:
+break;
+}
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(void) v29_tx_power(v29_tx_state_t *s, float power)
+{
+/* The constellation does not maintain constant average power as we change bit rates.
+We need to scale the gain we get here by a bit rate specific scaling factor each
+time we restart the modem. */
+s->base_gain = powf(10.0f, (power - DBM0_MAX_POWER)/20.0f)*32768.0f/TX_PULSESHAPER_GAIN;
+set_working_gain(s);
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(void) v29_tx_set_get_bit(v29_tx_state_t *s, get_bit_func_t get_bit, void *user_data)
+{
+if (s->get_bit == s->current_get_bit)
+s->current_get_bit = get_bit;
+s->get_bit = get_bit;
+s->get_bit_user_data = user_data;
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(void) v29_tx_set_modem_status_handler(v29_tx_state_t *s, modem_tx_status_func_t handler, void *user_data)
+{
+s->status_handler = handler;
+s->status_user_data = user_data;
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(logging_state_t *) v29_tx_get_logging_state(v29_tx_state_t *s)
+{
+return &s->logging;
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(int) v29_tx_restart(v29_tx_state_t *s, int bit_rate, int tep)
+{
+span_log(&s->logging, SPAN_LOG_FLOW, "Restarting V.29\n");
+s->bit_rate = bit_rate;
+set_working_gain(s);
+switch (s->bit_rate)
+{
+case 9600:
+s->training_offset = 0;
+break;
+case 7200:
+s->training_offset = 2;
+break;
+case 4800:
+s->training_offset = 4;
+break;
+default:
+return -1;
+}
+#if defined(SPANDSP_USE_FIXED_POINT)
+memset(s->rrc_filter, 0, sizeof(s->rrc_filter));
+#else
+cvec_zerof(s->rrc_filter, sizeof(s->rrc_filter)/sizeof(s->rrc_filter[0]));
+#endif
+s->rrc_filter_step = 0;
+s->scramble_reg = 0;
+s->training_scramble_reg = 0x2A;
+s->in_training = TRUE;
+s->training_step = (tep)  ?  V29_TRAINING_SEG_TEP  :  V29_TRAINING_SEG_1;
+s->carrier_phase = 0;
+s->baud_phase = 0;
+s->constellation_state = 0;
+s->current_get_bit = fake_get_bit;
+return 0;
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(v29_tx_state_t *) v29_tx_init(v29_tx_state_t *s, int bit_rate, int tep, get_bit_func_t get_bit, void *user_data)
+{
+switch (bit_rate)
+{
+case 9600:
+case 7200:
+case 4800:
+break;
+default:
+return NULL;
+}
+if (s == NULL)
+{
+if ((s = (v29_tx_state_t *) malloc(sizeof(*s))) == NULL)
+return NULL;
+}
+memset(s, 0, sizeof(*s));
+span_log_init(&s->logging, SPAN_LOG_NONE, NULL);
+span_log_set_protocol(&s->logging, "V.29 TX");
+s->get_bit = get_bit;
+s->get_bit_user_data = user_data;
+s->carrier_phase_rate = dds_phase_ratef(CARRIER_NOMINAL_FREQ);
+v29_tx_power(s, -14.0f);
+v29_tx_restart(s, bit_rate, tep);
+return s;
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(int) v29_tx_release(v29_tx_state_t *s)
+{
+return 0;
+}
+/*- End of function --------------------------------------------------------*/
+SPAN_DECLARE(int) v29_tx_free(v29_tx_state_t *s)
+{
+free(s);
+return 0;
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/

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comparison spandsp-0.0.6pre17/src/v29tx.c @ 4:26cd8f1ef0b1