--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/v27ter_rx.h	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,164 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * v27ter_rx.h - ITU V.27ter modem receive part
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2003 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: v27ter_rx.h,v 1.61 2009/07/09 13:52:09 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_SPANDSP_V27TER_RX_H_)
+#define _SPANDSP_V27TER_RX_H_
+
+/*! \page v27ter_rx_page The V.27ter receiver
+
+\section v27ter_rx_page_sec_1 What does it do?
+The V.27ter receiver implements the receive side of a V.27ter modem. This can operate
+at data rates of 4800 and 2400 bits/s. The audio input is a stream of 16 bit samples,
+at 8000 samples/second. The transmit and receive side of V.27ter modems operate
+independantly. V.27ter is mostly used for FAX transmission, where it provides the
+standard 4800 bits/s rate (the 2400 bits/s mode is not used for FAX). 
+
+\section v27ter_rx_page_sec_2 How does it work?
+V.27ter defines two modes of operation. One uses 8-PSK at 1600 baud, giving 4800bps.
+The other uses 4-PSK at 1200 baud, giving 2400bps. A training sequence is specified
+at the start of transmission, which makes the design of a V.27ter receiver relatively
+straightforward.
+*/
+
+/*!
+    V.27ter modem receive side descriptor. This defines the working state for a
+    single instance of a V.27ter modem receiver.
+*/
+typedef struct v27ter_rx_state_s v27ter_rx_state_t;
+
+#if defined(__cplusplus)
+extern "C"
+{
+#endif
+
+/*! Initialise a V.27ter modem receive context.
+    \brief Initialise a V.27ter modem receive context.
+    \param s The modem context.
+    \param bit_rate The bit rate of the modem. Valid values are 2400 and 4800.
+    \param put_bit The callback routine used to put the received data.
+    \param user_data An opaque pointer passed to the put_bit routine.
+    \return A pointer to the modem context, or NULL if there was a problem. */
+SPAN_DECLARE(v27ter_rx_state_t *) v27ter_rx_init(v27ter_rx_state_t *s, int bit_rate, put_bit_func_t put_bit, void *user_data);
+
+/*! Reinitialise an existing V.27ter modem receive context.
+    \brief Reinitialise an existing V.27ter modem receive context.
+    \param s The modem context.
+    \param bit_rate The bit rate of the modem. Valid values are 2400 and 4800.
+    \param old_train TRUE if a previous trained values are to be reused.
+    \return 0 for OK, -1 for bad parameter */
+SPAN_DECLARE(int) v27ter_rx_restart(v27ter_rx_state_t *s, int bit_rate, int old_train);
+
+/*! Release a V.27ter modem receive context.
+    \brief Release a V.27ter modem receive context.
+    \param s The modem context.
+    \return 0 for OK */
+SPAN_DECLARE(int) v27ter_rx_release(v27ter_rx_state_t *s);
+
+/*! Free a V.27ter modem receive context.
+    \brief Free a V.27ter modem receive context.
+    \param s The modem context.
+    \return 0 for OK */
+SPAN_DECLARE(int) v27ter_rx_free(v27ter_rx_state_t *s);
+
+/*! Get the logging context associated with a V.27ter modem receive context.
+    \brief Get the logging context associated with a V.27ter modem receive context.
+    \param s The modem context.
+    \return A pointer to the logging context */
+SPAN_DECLARE(logging_state_t *) v27ter_rx_get_logging_state(v27ter_rx_state_t *s);
+
+/*! Change the put_bit function associated with a V.27ter modem receive context.
+    \brief Change the put_bit function associated with a V.27ter modem receive context.
+    \param s The modem context.
+    \param put_bit The callback routine used to handle received bits.
+    \param user_data An opaque pointer. */
+SPAN_DECLARE(void) v27ter_rx_set_put_bit(v27ter_rx_state_t *s, put_bit_func_t put_bit, void *user_data);
+
+/*! Change the modem status report function associated with a V.27ter modem receive context.
+    \brief Change the modem status report function associated with a V.27ter modem receive context.
+    \param s The modem context.
+    \param handler The callback routine used to report modem status changes.
+    \param user_data An opaque pointer. */
+SPAN_DECLARE(void) v27ter_rx_set_modem_status_handler(v27ter_rx_state_t *s, modem_rx_status_func_t handler, void *user_data);
+
+/*! Process a block of received V.27ter modem audio samples.
+    \brief Process a block of received V.27ter modem audio samples.
+    \param s The modem context.
+    \param amp The audio sample buffer.
+    \param len The number of samples in the buffer.
+    \return The number of samples unprocessed.
+*/
+SPAN_DECLARE_NONSTD(int) v27ter_rx(v27ter_rx_state_t *s, const int16_t amp[], int len);
+
+/*! Fake processing of a missing block of received V.27ter modem audio samples.
+    (e.g due to packet loss).
+    \brief Fake processing of a missing block of received V.27ter modem audio samples.
+    \param s The modem context.
+    \param len The number of samples to fake.
+    \return The number of samples unprocessed.
+*/
+SPAN_DECLARE(int) v27ter_rx_fillin(v27ter_rx_state_t *s, int len);
+
+/*! Get a snapshot of the current equalizer coefficients.
+    \brief Get a snapshot of the current equalizer coefficients.
+    \param coeffs The vector of complex coefficients.
+    \return The number of coefficients in the vector. */
+SPAN_DECLARE(int) v27ter_rx_equalizer_state(v27ter_rx_state_t *s, complexf_t **coeffs);
+
+/*! Get the current received carrier frequency.
+    \param s The modem context.
+    \return The frequency, in Hertz. */
+SPAN_DECLARE(float) v27ter_rx_carrier_frequency(v27ter_rx_state_t *s);
+
+/*! Get the current symbol timing correction since startup.
+    \param s The modem context.
+    \return The correction. */
+SPAN_DECLARE(float) v27ter_rx_symbol_timing_correction(v27ter_rx_state_t *s);
+
+/*! Get a current received signal power.
+    \param s The modem context.
+    \return The signal power, in dBm0. */
+SPAN_DECLARE(float) v27ter_rx_signal_power(v27ter_rx_state_t *s);
+
+/*! Set the power level at which the carrier detection will cut in
+    \param s The modem context.
+    \param cutoff The signal cutoff power, in dBm0. */
+SPAN_DECLARE(void) v27ter_rx_signal_cutoff(v27ter_rx_state_t *s, float cutoff);
+
+/*! Set a handler routine to process QAM status reports
+    \param s The modem context.
+    \param handler The handler routine.
+    \param user_data An opaque pointer passed to the handler routine. */
+SPAN_DECLARE(void) v27ter_rx_set_qam_report_handler(v27ter_rx_state_t *s, qam_report_handler_t handler, void *user_data);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/