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5
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1 /*
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2 * SpanDSP - a series of DSP components for telephony
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3 *
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4 * telephony.h - some very basic telephony definitions
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5 *
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6 * Written by Steve Underwood <steveu@coppice.org>
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7 *
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8 * Copyright (C) 2003 Steve Underwood
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9 *
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10 * All rights reserved.
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11 *
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12 * This program is free software; you can redistribute it and/or modify
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13 * it under the terms of the GNU General Public License version 2, as
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14 * published by the Free Software Foundation.
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15 *
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16 * This program is distributed in the hope that it will be useful,
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17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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19 * GNU General Public License for more details.
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20 *
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21 * You should have received a copy of the GNU General Public License
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22 * along with this program; if not, write to the Free Software
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23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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24 *
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25 * $Id: telephony.h,v 1.9 2006/11/28 16:59:57 steveu Exp $
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26 */
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27
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28 #if !defined(_TELEPHONY_H_)
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29 #define _TELEPHONY_H_
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30
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31 #define SAMPLE_RATE 8000
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32
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33 /* This is based on A-law, but u-law is only 0.03dB different */
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34 #define DBM0_MAX_POWER (3.14f + 3.02f)
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35 #define DBM0_MAX_SINE_POWER (3.14f)
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36 /* This is based on the ITU definition of dbOv in G.100.1 */
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37 #define DBOV_MAX_POWER (0.0f)
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38 #define DBOV_MAX_SINE_POWER (-3.02f)
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39
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40 /*! \brief A handler for pure receive. The buffer cannot be altered. */
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41 typedef int (span_rx_handler_t)(void *s, const int16_t amp[], int len);
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42
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43 /*! \brief A handler for receive, where the buffer can be altered. */
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44 typedef int (span_mod_handler_t)(void *s, int16_t amp[], int len);
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45
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46 /*! \brief A handler for transmit, where the buffer will be filled. */
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47 typedef int (span_tx_handler_t)(void *s, int16_t amp[], int max_len);
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48
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49 #define ms_to_samples(t) (((t)*SAMPLE_RATE)/1000)
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50
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51 #if !defined(FALSE)
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52 #define FALSE 0
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53 #endif
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54 #if !defined(TRUE)
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55 #define TRUE (!FALSE)
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56 #endif
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57
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58 #if defined(__cplusplus)
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59 /* C++ doesn't seem to have sane rounding functions/macros yet */
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60 #ifndef _MSC_VER
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61 #define lrint(x) ((long int) (x))
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62 #define lrintf(x) ((long int) (x))
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63 #endif
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64 #endif
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65
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66 #endif
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67 /*- End of file ------------------------------------------------------------*/
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