00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * telephony.h - some very basic telephony definitions 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2003 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 Lesser General Public License version 2.1, 00014 * as published by the Free Software Foundation. 00015 * 00016 * This program is distributed in the hope that it will be useful, 00017 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00018 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00019 * GNU Lesser General Public License for more details. 00020 * 00021 * You should have received a copy of the GNU Lesser General Public 00022 * License along with this program; if not, write to the Free Software 00023 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00024 * 00025 * $Id: telephony.h,v 1.12 2008/04/17 14:27:01 steveu Exp $ 00026 */ 00027 00028 #if !defined(_SPANDSP_TELEPHONY_H_) 00029 #define _SPANDSP_TELEPHONY_H_ 00030 00031 #define SAMPLE_RATE 8000 00032 00033 /* This is based on A-law, but u-law is only 0.03dB different */ 00034 #define DBM0_MAX_POWER (3.14f + 3.02f) 00035 #define DBM0_MAX_SINE_POWER (3.14f) 00036 /* This is based on the ITU definition of dbOv in G.100.1 */ 00037 #define DBOV_MAX_POWER (0.0f) 00038 #define DBOV_MAX_SINE_POWER (-3.02f) 00039 00040 /*! \brief A handler for pure receive. The buffer cannot be altered. */ 00041 typedef int (span_rx_handler_t)(void *s, const int16_t amp[], int len); 00042 00043 /*! \brief A handler for receive, where the buffer can be altered. */ 00044 typedef int (span_mod_handler_t)(void *s, int16_t amp[], int len); 00045 00046 /*! \brief A handler for transmit, where the buffer will be filled. */ 00047 typedef int (span_tx_handler_t)(void *s, int16_t amp[], int max_len); 00048 00049 #define ms_to_samples(t) (((t)*SAMPLE_RATE)/1000) 00050 00051 #if !defined(FALSE) 00052 #define FALSE 0 00053 #endif 00054 #if !defined(TRUE) 00055 #define TRUE (!FALSE) 00056 #endif 00057 00058 #if defined(__cplusplus) 00059 /* C++ doesn't seem to have sane rounding functions/macros yet */ 00060 #ifndef _MSC_VER 00061 #define lrint(x) ((long int) (x)) 00062 #define lrintf(x) ((long int) (x)) 00063 #endif 00064 #endif 00065 00066 #endif 00067 /*- End of file ------------------------------------------------------------*/