54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
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/*---------------------------------------------------------------------------*\
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FILE........: codec2_fm.h
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AUTHOR......: David Rowe
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DATE CREATED: February 2015
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Functions that implement analog FM, see also octave/fm.m.
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\*---------------------------------------------------------------------------*/
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/*
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Copyright (C) 2015 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 __CODEC2_FM__
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#define __CODEC2_FM__
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#include "comp.h"
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struct FM {
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float Fs; /* setme: sample rate */
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float fm_max; /* setme: maximum modulation frequency */
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float fd; /* setme: maximum deviation */
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float fc; /* setme: carrier frequency */
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COMP *rx_bb;
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COMP rx_bb_filt_prev;
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float *rx_dem_mem;
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float tx_phase;
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int nsam;
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COMP lo_phase;
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};
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struct FM *fm_create(int nsam);
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void fm_destroy(struct FM *fm_states);
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void fm_demod(struct FM *fm, float rx_out[], float rx[]);
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void fm_mod(struct FM *fm, float tx_in[], float tx_out[]);
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void fm_mod_comp(struct FM *fm_states, float tx_in[], COMP tx_out[]);
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#endif
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