--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/private/echo.h	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,94 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * private/echo.h - An echo cancellor, suitable for electrical and acoustic
+ *	                cancellation. This code does not currently comply with
+ *	                any relevant standards (e.g. G.164/5/7/8).
+ *
+ * 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: echo.h,v 1.1 2009/09/22 13:11:04 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_SPANDSP_PRIVATE_ECHO_H_)
+#define _SPANDSP_PRIVATE_ECHO_H_
+
+/*!
+    G.168 echo canceller descriptor. This defines the working state for a line
+    echo canceller.
+*/
+struct echo_can_state_s
+{
+    int tx_power[4];
+    int rx_power[3];
+    int clean_rx_power;
+
+    int rx_power_threshold;
+    int nonupdate_dwell;
+
+    int curr_pos;
+	
+    int taps;
+    int tap_mask;
+    int adaption_mode;
+    
+    int32_t supp_test1;
+    int32_t supp_test2;
+    int32_t supp1;
+    int32_t supp2;
+    int vad;
+    int cng;
+
+    int16_t geigel_max;
+    int geigel_lag;
+    int dtd_onset;
+    int tap_set;
+    int tap_rotate_counter;
+
+    int32_t latest_correction;  /* Indication of the magnitude of the latest
+                                   adaption, or a code to indicate why adaption
+                                   was skipped, for test purposes */
+    int32_t last_acf[28];
+    int narrowband_count;
+    int narrowband_score;
+
+    fir16_state_t fir_state;
+    /*! Echo FIR taps (16 bit version) */
+    int16_t *fir_taps16[4];
+    /*! Echo FIR taps (32 bit version) */
+    int32_t *fir_taps32;
+
+    /* DC and near DC blocking filter states */
+    int32_t tx_hpf[2];
+    int32_t rx_hpf[2];
+   
+    /* Parameters for the optional Hoth noise generator */
+    int cng_level;
+    int cng_rndnum;
+    int cng_filter;
+    
+    /* Snapshot sample of coeffs used for development */
+    int16_t *snapshot;       
+};
+
+#endif
+/*- End of file ------------------------------------------------------------*/