00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * super_tone_tx.h - Flexible telephony supervisory tone generation. 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2001 Steve Underwood 00009 * 00010 * All rights reserved. 00011 * 00012 * This program is free software; you can redistribute it and/or modify 00013 * it under the terms of the GNU General Public License as published by 00014 * the Free Software Foundation; either version 2 of the License, or 00015 * (at your option) any later version. 00016 * 00017 * This program is distributed in the hope that it will be useful, 00018 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00019 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00020 * GNU General Public License for more details. 00021 * 00022 * You should have received a copy of the GNU General Public License 00023 * along with this program; if not, write to the Free Software 00024 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00025 * 00026 * $Id: super_tone_tx.h,v 1.5 2005/11/25 14:52:00 steveu Exp $ 00027 */ 00028 00029 #if !defined(_SUPER_TONE_TX_H_) 00030 #define _SUPER_TONE_TX_H_ 00031 00032 /*! \page super_tone_tx_page Supervisory tone generation 00033 00034 \section super_tone_tx_page_sec_1 What does it do? 00035 00036 The supervisory tone generator may be configured to generate most of the world's 00037 telephone supervisory tones - things like ringback, busy, number unobtainable, 00038 and so on. It uses tree structure tone descriptions, which can deal with quite 00039 complex cadence patterns. 00040 00041 \section super_tone_tx_page_sec_2 How does it work? 00042 00043 */ 00044 00045 typedef struct super_tone_tx_step_s super_tone_tx_step_t; 00046 00047 typedef struct 00048 { 00049 int32_t phase_rate[2]; 00050 int gain[2]; 00051 uint32_t phase[2]; 00052 int current_position; 00053 int level; 00054 super_tone_tx_step_t *levels[4]; 00055 int cycles[4]; 00056 } super_tone_tx_state_t; 00057 00058 struct super_tone_tx_step_s 00059 { 00060 int32_t phase_rate[2]; 00061 int gain[2]; 00062 int tone; 00063 int length; 00064 int cycles; 00065 super_tone_tx_step_t *next; 00066 super_tone_tx_step_t *nest; 00067 }; 00068 00069 super_tone_tx_step_t *super_tone_tx_make_step(super_tone_tx_step_t *s, 00070 float f1, 00071 float l1, 00072 float f2, 00073 float l2, 00074 int length, 00075 int cycles); 00076 00077 void super_tone_tx_free(super_tone_tx_step_t *s); 00078 00079 /*! Initialise a supervisory tone generator. 00080 \brief Initialise a supervisory tone generator. 00081 \param s The supervisory tone generator context. 00082 \param tree The supervisory tone tree to be generated. 00083 \return The supervisory tone generator context. */ 00084 super_tone_tx_state_t *super_tone_tx_init(super_tone_tx_state_t *s, super_tone_tx_step_t *tree); 00085 00086 /*! Generate a block of audio samples for a supervisory tone pattern. 00087 \brief Generate a block of audio samples for a supervisory tone pattern. 00088 \param tone The supervisory tone context. 00089 \param amp The audio sample buffer. 00090 \param max_samples The maximum number of samples to be generated. 00091 \return The number of samples generated. */ 00092 int super_tone_tx(super_tone_tx_state_t *s, int16_t amp[], int max_samples); 00093 00094 #endif 00095 /*- End of file ------------------------------------------------------------*/