97 lines
3.3 KiB
C
97 lines
3.3 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* awgn.h - An additive Gaussian white noise generator
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2001 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id: awgn.h,v 1.18 2009/02/10 13:06:47 steveu Exp $
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*/
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/*! \file */
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/* This code is based on some demonstration code in a research
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paper somewhere. I can't track down where I got the original from,
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so that due recognition can be given. The original had no explicit
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copyright notice, and I hope nobody objects to its use here.
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Having a reasonable Gaussian noise generator is pretty important for
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telephony testing (in fact, pretty much any DSP testing), and this
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one seems to have served me OK. Since the generation of Gaussian
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noise is only for test purposes, and not a core system component,
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I don't intend to worry excessively about copyright issues, unless
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someone worries me.
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The non-core nature of this code also explains why it is unlikely
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to ever be optimised. */
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#if !defined(_SPANDSP_AWGN_H_)
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#define _SPANDSP_AWGN_H_
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/*! \page awgn_page Additive white gaussian noise (AWGN) generation
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\section awgn_page_sec_1 What does it do?
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Adding noise is not the most useful thing in most DSP applications, but it is
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awfully useful for test suites.
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\section awgn_page_sec_2 How does it work?
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This code is based on some demonstration code in a research paper somewhere. I
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can't track down where I got the original from, so that due recognition can be
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given. The original had no explicit copyright notice, and I hope nobody objects
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to its use here.
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Having a reasonable Gaussian noise generator is pretty important for telephony
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testing (in fact, pretty much any DSP testing), and this one seems to have
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served me OK. Since the generation of Gaussian noise is only for test purposes,
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and not a core system component, I don't intend to worry excessively about
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copyright issues, unless someone worries me.
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The non-core nature of this code also explains why it is unlikely to ever be
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optimised.
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*/
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/*!
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AWGN generator descriptor. This contains all the state information for an AWGN generator.
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*/
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typedef struct awgn_state_s awgn_state_t;
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#if defined(__cplusplus)
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extern "C"
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{
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#endif
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SPAN_DECLARE(awgn_state_t *) awgn_init_dbm0(awgn_state_t *s, int idum, float level);
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SPAN_DECLARE(awgn_state_t *) awgn_init_dbov(awgn_state_t *s, int idum, float level);
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SPAN_DECLARE(int) awgn_release(awgn_state_t *s);
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SPAN_DECLARE(int) awgn_free(awgn_state_t *s);
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SPAN_DECLARE(int16_t) awgn(awgn_state_t *s);
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#if defined(__cplusplus)
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}
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#endif
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#endif
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/*- End of file ------------------------------------------------------------*/
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