Mercurial > hg > audiostuff
comparison spandsp-0.0.6pre17/src/spandsp/awgn.h @ 4:26cd8f1ef0b1
import spandsp-0.0.6pre17
author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
---|---|
date | Fri, 25 Jun 2010 15:50:58 +0200 |
parents | |
children |
comparison
equal
deleted
inserted
replaced
3:c6c5a16ce2f2 | 4:26cd8f1ef0b1 |
---|---|
1 /* | |
2 * SpanDSP - a series of DSP components for telephony | |
3 * | |
4 * awgn.h - An additive Gaussian white noise generator | |
5 * | |
6 * Written by Steve Underwood <steveu@coppice.org> | |
7 * | |
8 * Copyright (C) 2001 Steve Underwood | |
9 * | |
10 * All rights reserved. | |
11 * | |
12 * This program is free software; you can redistribute it and/or modify | |
13 * it under the terms of the GNU Lesser General Public License version 2.1, | |
14 * as published by the Free Software Foundation. | |
15 * | |
16 * This program is distributed in the hope that it will be useful, | |
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 * GNU Lesser General Public License for more details. | |
20 * | |
21 * You should have received a copy of the GNU Lesser General Public | |
22 * License along with this program; if not, write to the Free Software | |
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
24 * | |
25 * $Id: awgn.h,v 1.18 2009/02/10 13:06:47 steveu Exp $ | |
26 */ | |
27 | |
28 /*! \file */ | |
29 | |
30 /* This code is based on some demonstration code in a research | |
31 paper somewhere. I can't track down where I got the original from, | |
32 so that due recognition can be given. The original had no explicit | |
33 copyright notice, and I hope nobody objects to its use here. | |
34 | |
35 Having a reasonable Gaussian noise generator is pretty important for | |
36 telephony testing (in fact, pretty much any DSP testing), and this | |
37 one seems to have served me OK. Since the generation of Gaussian | |
38 noise is only for test purposes, and not a core system component, | |
39 I don't intend to worry excessively about copyright issues, unless | |
40 someone worries me. | |
41 | |
42 The non-core nature of this code also explains why it is unlikely | |
43 to ever be optimised. */ | |
44 | |
45 #if !defined(_SPANDSP_AWGN_H_) | |
46 #define _SPANDSP_AWGN_H_ | |
47 | |
48 /*! \page awgn_page Additive white gaussian noise (AWGN) generation | |
49 | |
50 \section awgn_page_sec_1 What does it do? | |
51 Adding noise is not the most useful thing in most DSP applications, but it is | |
52 awfully useful for test suites. | |
53 | |
54 \section awgn_page_sec_2 How does it work? | |
55 | |
56 This code is based on some demonstration code in a research paper somewhere. I | |
57 can't track down where I got the original from, so that due recognition can be | |
58 given. The original had no explicit copyright notice, and I hope nobody objects | |
59 to its use here. | |
60 | |
61 Having a reasonable Gaussian noise generator is pretty important for telephony | |
62 testing (in fact, pretty much any DSP testing), and this one seems to have | |
63 served me OK. Since the generation of Gaussian noise is only for test purposes, | |
64 and not a core system component, I don't intend to worry excessively about | |
65 copyright issues, unless someone worries me. | |
66 | |
67 The non-core nature of this code also explains why it is unlikely to ever be | |
68 optimised. | |
69 */ | |
70 | |
71 /*! | |
72 AWGN generator descriptor. This contains all the state information for an AWGN generator. | |
73 */ | |
74 typedef struct awgn_state_s awgn_state_t; | |
75 | |
76 #if defined(__cplusplus) | |
77 extern "C" | |
78 { | |
79 #endif | |
80 | |
81 SPAN_DECLARE(awgn_state_t *) awgn_init_dbm0(awgn_state_t *s, int idum, float level); | |
82 | |
83 SPAN_DECLARE(awgn_state_t *) awgn_init_dbov(awgn_state_t *s, int idum, float level); | |
84 | |
85 SPAN_DECLARE(int) awgn_release(awgn_state_t *s); | |
86 | |
87 SPAN_DECLARE(int) awgn_free(awgn_state_t *s); | |
88 | |
89 SPAN_DECLARE(int16_t) awgn(awgn_state_t *s); | |
90 | |
91 #if defined(__cplusplus) | |
92 } | |
93 #endif | |
94 | |
95 #endif | |
96 /*- End of file ------------------------------------------------------------*/ |