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111 lines
4.4 KiB
C
111 lines
4.4 KiB
C
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/*---------------------------------------------------------------------------*\
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FILE........: codec2_fdmdv.h
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AUTHOR......: David Rowe
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DATE CREATED: April 14 2012
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A 1400 bit/s (nominal) Frequency Division Multiplexed Digital Voice
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(FDMDV) modem. Used for digital audio over HF SSB. See
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README_fdmdv.txt for more information, and fdmdv_mod.c and
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fdmdv_demod.c for example usage.
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The name codec2_fdmdv.h is used to make it unique when "make
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installed".
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References:
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[1] http://n1su.com/fdmdv/FDMDV_Docs_Rel_1_4b.pdf
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\*---------------------------------------------------------------------------*/
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/*
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Copyright (C) 2012 David Rowe
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All rights reserved.
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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, as
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published by the Free Software Foundation. This program is
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distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __FDMDV__
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#define __FDMDV__
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/* set up the calling convention for DLL function import/export for
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WIN32 cross compiling */
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#ifdef __CODEC2_WIN32__
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#ifdef __CODEC2_BUILDING_DLL__
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#define CODEC2_WIN32SUPPORT __declspec(dllexport) __stdcall
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#else
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#define CODEC2_WIN32SUPPORT __declspec(dllimport) __stdcall
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#endif
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#else
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#define CODEC2_WIN32SUPPORT
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#endif
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#include "codec2/comp.h"
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#include "modem_stats.h"
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#define FDMDV_NC 14 /* default number of data carriers */
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#define FDMDV_NC_MAX 20 /* maximum number of data carriers */
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#define FDMDV_BITS_PER_FRAME 28 /* 20ms frames, for nominal 1400 bit/s */
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#define FDMDV_NOM_SAMPLES_PER_FRAME 160 /* modulator output samples/frame and nominal demod samples/frame */
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/* at 8000 Hz sample rate */
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#define FDMDV_MAX_SAMPLES_PER_FRAME 200 /* max demod samples/frame, use this to allocate storage */
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#define FDMDV_SCALE 1000 /* suggested scaling for 16 bit shorts */
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#define FDMDV_FCENTRE 1500 /* Centre frequency, Nc/2 carriers below this, Nc/2 carriers above (Hz) */
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/* 8 to 48 kHz sample rate conversion */
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#define FDMDV_OS 2 /* oversampling rate */
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#define FDMDV_OS_TAPS_16K 48 /* number of OS filter taps at 16kHz */
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#define FDMDV_OS_TAPS_8K (FDMDV_OS_TAPS_16K/FDMDV_OS) /* number of OS filter taps at 8kHz */
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namespace FreeDV
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{
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/* FDMDV states and stats structures */
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struct FDMDV;
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struct FDMDV * fdmdv_create(int Nc);
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void fdmdv_destroy(struct FDMDV *fdmdv_state);
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void fdmdv_use_old_qpsk_mapping(struct FDMDV *fdmdv_state);
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int fdmdv_bits_per_frame(struct FDMDV *fdmdv_state);
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float fdmdv_get_fsep(struct FDMDV *fdmdv_state);
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void fdmdv_set_fsep(struct FDMDV *fdmdv_state, float fsep);
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void fdmdv_mod(struct FDMDV *fdmdv_state, COMP tx_fdm[], int tx_bits[], int *sync_bit);
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void fdmdv_demod(struct FDMDV *fdmdv_state, int rx_bits[], int *reliable_sync_bit, COMP rx_fdm[], int *nin);
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void fdmdv_get_test_bits(struct FDMDV *fdmdv_state, int tx_bits[]);
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int fdmdv_error_pattern_size(struct FDMDV *fdmdv_state);
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void fdmdv_put_test_bits(struct FDMDV *f, int *sync, short error_pattern[], int *bit_errors, int *ntest_bits, int rx_bits[]);
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void fdmdv_get_demod_stats(struct FDMDV *fdmdv_state, struct MODEM_STATS *stats);
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void fdmdv_8_to_16(float out16k[], float in8k[], int n);
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void fdmdv_8_to_16_short(short out16k[], short in8k[], int n);
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void fdmdv_16_to_8(float out8k[], float in16k[], int n);
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void fdmdv_16_to_8_short(short out8k[], short in16k[], int n);
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void fdmdv_freq_shift(COMP rx_fdm_fcorr[], COMP rx_fdm[], float foff, COMP *foff_phase_rect, int nin);
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/* debug/development function(s) */
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void fdmdv_dump_osc_mags(struct FDMDV *f);
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void fdmdv_simulate_channel(float *sig_pwr_av, COMP samples[], int nin, float target_snr);
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} // FreeDV
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#endif
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