--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/awgn.h	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,96 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * awgn.h - An additive Gaussian white noise generator
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2001 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: awgn.h,v 1.18 2009/02/10 13:06:47 steveu Exp $
+ */
+
+/*! \file */
+
+/* This code is based on some demonstration code in a research
+   paper somewhere. I can't track down where I got the original from,
+   so that due recognition can be given. The original had no explicit
+   copyright notice, and I hope nobody objects to its use here.
+   
+   Having a reasonable Gaussian noise generator is pretty important for
+   telephony testing (in fact, pretty much any DSP testing), and this
+   one seems to have served me OK. Since the generation of Gaussian
+   noise is only for test purposes, and not a core system component,
+   I don't intend to worry excessively about copyright issues, unless
+   someone worries me.
+        
+   The non-core nature of this code also explains why it is unlikely
+   to ever be optimised. */
+
+#if !defined(_SPANDSP_AWGN_H_)
+#define _SPANDSP_AWGN_H_
+
+/*! \page awgn_page Additive white gaussian noise (AWGN) generation
+
+\section awgn_page_sec_1 What does it do?
+Adding noise is not the most useful thing in most DSP applications, but it is
+awfully useful for test suites. 
+
+\section awgn_page_sec_2 How does it work?
+
+This code is based on some demonstration code in a research paper somewhere. I
+can't track down where I got the original from, so that due recognition can be
+given. The original had no explicit copyright notice, and I hope nobody objects
+to its use here. 
+
+Having a reasonable Gaussian noise generator is pretty important for telephony
+testing (in fact, pretty much any DSP testing), and this one seems to have
+served me OK. Since the generation of Gaussian noise is only for test purposes,
+and not a core system component, I don't intend to worry excessively about
+copyright issues, unless someone worries me. 
+
+The non-core nature of this code also explains why it is unlikely to ever be
+optimised.
+*/
+
+/*!
+    AWGN generator descriptor. This contains all the state information for an AWGN generator.
+ */
+typedef struct awgn_state_s awgn_state_t;
+
+#if defined(__cplusplus)
+extern "C"
+{
+#endif
+
+SPAN_DECLARE(awgn_state_t *) awgn_init_dbm0(awgn_state_t *s, int idum, float level);
+
+SPAN_DECLARE(awgn_state_t *) awgn_init_dbov(awgn_state_t *s, int idum, float level);
+
+SPAN_DECLARE(int) awgn_release(awgn_state_t *s);
+
+SPAN_DECLARE(int) awgn_free(awgn_state_t *s);
+
+SPAN_DECLARE(int16_t) awgn(awgn_state_t *s);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/