--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/spandsp/v22bis.h	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,293 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * v22bis.h - ITU V.22bis modem receive part
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2004 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: v22bis.h,v 1.19 2006/10/24 13:45:28 steveu Exp $
+ */
+
+/*! \file */
+
+/*! \page v22bis_page The V.22bis modem
+\section v22bis_page_sec_1 What does it do?
+The V.22bis modem is a duplex modem for general data use on the PSTN, at rates
+of 1200 and 2400 bits/second. It is a compatible extension of the V.22 modem,
+which is a 1200 bits/second only design. It is a band-split design, using carriers
+of 1200Hz and 2400Hz. It is the fastest PSTN modem in general use which does not
+use echo-cancellation.
+
+\section v22bis__page_sec_2 How does it work?
+V.22bis uses 4PSK modulation at 1200 bits/second or 16QAM modulation at 2400
+bits/second. At 1200bps the symbols are so long that a fixed compromise equaliser
+is sufficient to recover the 4PSK signal reliably. At 2400bps an adaptive
+equaliser is necessary.
+
+The V.22bis training sequence includes sections which allow the modems to determine
+if the far modem can support (or is willing to support) 2400bps operation. The
+modems will automatically use 2400bps if both ends are willing to use that speed,
+or 1200bps if one or both ends to not acknowledge that 2400bps is OK.
+*/
+
+#if !defined(_V22BIS_H_)
+#define _V22BIS_H_
+
+#define V22BIS_EQUALIZER_LEN    7  /* this much to the left and this much to the right */
+#define V22BIS_EQUALIZER_MASK   15 /* one less than a power of 2 >= (2*V22BIS_EQUALIZER_LEN + 1) */
+
+#define V22BIS_TX_FILTER_STEPS  9
+
+#define V22BIS_RX_FILTER_STEPS  37
+
+/*!
+    V.22bis modem receive side descriptor. This defines the working state for a
+    single instance of a V.22bis modem receiver.
+*/
+typedef struct
+{
+    /*! \brief The bit rate of the modem. Valid values are 1200 and 2400. */
+    int bit_rate;
+    /*! \brief TRUE is this is the calling side modem. */
+    int caller;
+    /*! \brief The callback function used to put each bit received. */
+    put_bit_func_t put_bit;
+    /*! \brief The callback function used to get the next bit to be transmitted. */
+    get_bit_func_t get_bit;
+    /*! \brief A user specified opaque pointer passed to the callback routines. */
+    void *user_data;
+
+    /* RECEIVE SECTION */
+
+    /*! \brief A callback function which may be enabled to report every symbol's
+               constellation position. */
+    qam_report_handler_t *qam_report;
+    /*! \brief A user specified opaque pointer passed to the qam_report callback
+               routine. */
+    void *qam_user_data;
+
+    /*! \brief The route raised cosine (RRC) pulse shaping filter buffer. */
+    float rx_rrc_filter[2*V22BIS_RX_FILTER_STEPS];
+    /*! \brief Current offset into the RRC pulse shaping filter buffer. */
+    int rx_rrc_filter_step;
+
+    /*! \brief The register for the data scrambler. */
+    unsigned int rx_scramble_reg;
+    /*! \brief A counter for the number of consecutive bits of repeating pattern through
+               the scrambler. */
+    int rx_scrambler_pattern_count;
+    /*! \brief 0 if receiving user data. A training stage value during training */
+    int rx_training;
+    int rx_training_count;
+    float training_error;
+    int carrier_present;
+
+    /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
+    uint32_t rx_carrier_phase;
+    /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
+    int32_t rx_carrier_phase_rate;
+    float carrier_track_p;
+    float carrier_track_i;
+
+    power_meter_t rx_power;
+    int32_t carrier_on_power;
+    int32_t carrier_off_power;
+    float agc_scaling;
+    
+    int rx_constellation_state;
+
+    float eq_delta;
+    /*! \brief The adaptive equalizer coefficients */
+    complexf_t eq_coeff[2*V22BIS_EQUALIZER_LEN + 1];
+    complexf_t eq_buf[V22BIS_EQUALIZER_MASK + 1];
+    /*! \brief Current offset into equalizer buffer. */
+    int eq_step;
+    int eq_put_step;
+
+    /*! \brief Integration variable for damping the Gardner algorithm tests. */
+    int gardner_integrate;
+    /*! \brief Current step size of Gardner algorithm integration. */
+    int gardner_step;
+    /*! \brief The total symbol timing correction since the carrier came up.
+               This is only for performance analysis purposes. */
+    int total_baud_timing_correction;
+    /*! \brief The current fractional phase of the baud timing. */
+    int rx_baud_phase;
+    
+    int sixteen_way_decisions;
+
+    /* TRANSMIT SECTION */
+
+    /*! \brief The gain factor needed to achieve the specified output power. */
+    float tx_gain;
+
+    /*! \brief The route raised cosine (RRC) pulse shaping filter buffer. */
+    complexf_t tx_rrc_filter[2*V22BIS_TX_FILTER_STEPS];
+    /*! \brief Current offset into the RRC pulse shaping filter buffer. */
+    int tx_rrc_filter_step;
+
+    /*! \brief The register for the data scrambler. */
+    unsigned int tx_scramble_reg;
+    /*! \brief A counter for the number of consecutive bits of repeating pattern through
+               the scrambler. */
+    int tx_scrambler_pattern_count;
+    /*! \brief 0 if transmitting user data. A training stage value during training */
+    int tx_training;
+    /*! \brief A counter used to track progress through sending the training sequence. */
+    int tx_training_count;
+
+    /*! \brief The current phase of the carrier (i.e. the DDS parameter). */
+    uint32_t tx_carrier_phase;
+    /*! \brief The update rate for the phase of the carrier (i.e. the DDS increment). */
+    int32_t tx_carrier_phase_rate;
+    /*! \brief The current phase of the guard tone (i.e. the DDS parameter). */
+    uint32_t guard_phase;
+    /*! \brief The update rate for the phase of the guard tone (i.e. the DDS increment). */
+    int32_t guard_phase_rate;
+    float guard_level;
+    /*! \brief The current fractional phase of the baud timing. */
+    int tx_baud_phase;
+    /*! \brief The code number for the current position in the constellation. */
+    int tx_constellation_state;
+    /*! \brief An indicator to mark that we are tidying up to stop transmission. */
+    int shutdown;
+    /*! \brief The get_bit function in use at any instant. */
+    get_bit_func_t current_get_bit;
+    
+    int detected_unscrambled_ones;
+    int detected_unscrambled_zeros;
+
+    int detected_unscrambled_ones_or_zeros;
+    int detected_unscrambled_0011_ending;
+    int detected_scrambled_ones_or_zeros_at_1200bps;
+    int detected_scrambled_ones_at_2400bps;
+
+    /*! \brief Error and flow logging control */
+    logging_state_t logging;
+} v22bis_state_t;
+
+extern const complexf_t v22bis_constellation[16];
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*! Reinitialise an existing V.22bis modem receive context.
+    \brief Reinitialise an existing V.22bis modem receive context.
+    \param s The modem context.
+    \param rate The bit rate of the modem. Valid values are 1200 and 2400.
+    \return 0 for OK, -1 for bad parameter */
+int v22bis_rx_restart(v22bis_state_t *s, int bit_rate);
+
+/*! Process a block of received V.22bis modem audio samples.
+    \brief Process a block of received V.22bis 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. */
+int v22bis_rx(v22bis_state_t *s, const int16_t amp[], 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. */
+int v22bis_rx_equalizer_state(v22bis_state_t *s, complexf_t **coeffs);
+
+/*! Get the current received carrier frequency.
+    \param s The modem context.
+    \return The frequency, in Hertz. */
+float v22bis_rx_carrier_frequency(v22bis_state_t *s);
+
+/*! Get the current symbol timing correction since startup.
+    \param s The modem context.
+    \return The correction. */
+float v22bis_rx_symbol_timing_correction(v22bis_state_t *s);
+
+/*! Get a current received signal power.
+    \param s The modem context.
+    \return The signal power, in dBm0. */
+float v22bis_rx_signal_power(v22bis_state_t *s);
+
+/*! 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. */
+void v22bis_rx_set_qam_report_handler(v22bis_state_t *s, qam_report_handler_t *handler, void *user_data);
+
+/*! Generate a block of V.22bis modem audio samples.
+    \brief Generate a block of V.22bis modem audio samples.
+    \param s The modem context.
+    \param amp The audio sample buffer.
+    \param len The number of samples to be generated.
+    \return The number of samples actually generated. */
+int v22bis_tx(v22bis_state_t *s, int16_t amp[], int len);
+
+/*! Adjust a V.22bis modem transmit context's power output.
+    \brief Adjust a V.22bis modem transmit context's output power.
+    \param s The modem context.
+    \param power The power level, in dBm0 */
+void v22bis_tx_power(v22bis_state_t *s, float power);
+
+/*! Reinitialise an existing V.22bis modem context, so it may be reused.
+    \brief Reinitialise an existing V.22bis modem context.
+    \param s The modem context.
+    \param bit_rate The bit rate of the modem. Valid values are 1200 and 2400.
+    \return 0 for OK, -1 for bad parameter. */
+int v22bis_restart(v22bis_state_t *s, int bit_rate);
+
+/*! Initialise a V.22bis modem context. This must be called before the first
+    use of the context, to initialise its contents.
+    \brief Initialise a V.22bis modem context.
+    \param s The modem context.
+    \param bit_rate The bit rate of the modem. Valid values are 1200 and 2400.
+    \param guard The guard tone option. 0 = none, 1 = 550Hz, 2 = 1800Hz.
+    \param caller TRUE if this is the calling modem.
+    \param get_bit The callback routine used to get the data to be transmitted.
+    \param put_bit The callback routine used to get the data to be transmitted.
+    \param user_data An opaque pointer, passed in calls to the get and put routines.
+    \return A pointer to the modem context, or NULL if there was a problem. */
+v22bis_state_t *v22bis_init(v22bis_state_t *s,
+                            int bit_rate,
+                            int guard,
+                            int caller,
+                            get_bit_func_t get_bit,
+                            put_bit_func_t put_bit,
+                            void *user_data);
+
+/*! Change the get_bit function associated with a V.2bis modem context.
+    \brief Change the get_bit function associated with a V.22bis modem context.
+    \param s The modem context.
+    \param get_bit The callback routine used to get the data to be transmitted.
+    \param user_data An opaque pointer. */
+void v22bis_set_get_bit(v22bis_state_t *s, get_bit_func_t get_bit, void *user_data);
+
+/*! Change the get_bit function associated with a V.2bis modem context.
+    \brief Change the put_bit function associated with a V.22bis modem context.
+    \param s The modem context.
+    \param put_bit The callback routine used to process the data received.
+    \param user_data An opaque pointer. */
+void v22bis_set_put_bit(v22bis_state_t *s, put_bit_func_t put_bit, void *user_data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/