127 lines
5.3 KiB
C
127 lines
5.3 KiB
C
/*---------------------------------------------------------------------------*\
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FILE........: cohpsk_internal.h
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AUTHOR......: David Rowe
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DATE CREATED: March 2015
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Functions that implement a coherent PSK FDM modem.
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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 __COHPSK_INTERNAL__
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#define __COHPSK_INTERNAL__
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#define NCT_SYMB_BUF (2*NSYMROWPILOT+2)
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#define ND 2 /* diversity factor ND 1 is no diveristy, ND we have orginal plus
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one copy */
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#define NSW 4 /* number of sync window frames */
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#define COHPSK_ND 2 /* diversity factor */
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#define COHPSK_M 100 /* oversampling rate */
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#define COHPSK_NSYM 6
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#define COHPSK_NFILTER (COHPSK_NSYM*COHPSK_M)
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#define COHPSK_EXCESS_BW 0.5 /* excess BW factor of root nyq filter */
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#define COHPSK_NT 5 /* number of symbols we estimate timing over */
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#include "fdmdv_internal.h"
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#include "kiss_fft.h"
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struct COHPSK {
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COMP ch_fdm_frame_buf[NSW*NSYMROWPILOT*COHPSK_M]; /* buffer of several frames of symbols from channel */
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float pilot2[2*NPILOTSFRAME][COHPSK_NC];
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float phi_[NSYMROWPILOT][COHPSK_NC*ND]; /* phase estimates for this frame of rx data symbols */
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float amp_[NSYMROW][COHPSK_NC*ND]; /* amplitude estimates for this frame of rx data symbols */
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COMP rx_symb[NSYMROWPILOT][COHPSK_NC*ND]; /* demodulated symbols */
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float f_est;
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COMP rx_filter_memory[COHPSK_NC*ND][COHPSK_NFILTER];
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COMP ct_symb_buf[NCT_SYMB_BUF][COHPSK_NC*ND];
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int ct; /* coarse timing offset in symbols */
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float rx_timing; /* fine timing for last symbol in frame */
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int nin; /* number of samples to input for next symbol */
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float f_fine_est;
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COMP ff_rect;
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COMP ff_phase;
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COMP ct_symb_ff_buf[NSYMROWPILOT+2][COHPSK_NC*ND];
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int sync;
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int sync_timer;
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int frame;
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float ratio;
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float sig_rms;
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float noise_rms;
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struct FDMDV *fdmdv;
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int verbose;
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int *ptest_bits_coh_tx;
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int *ptest_bits_coh_rx[2];
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int *ptest_bits_coh_end;
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/* counting bit errors using pilots */
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int npilotbits;
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int npilotbiterrors;
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/* optional log variables used for testing Octave to C port */
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COMP *rx_baseband_log;
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int rx_baseband_log_col_index;
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int rx_baseband_log_col_sz;
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COMP *rx_filt_log;
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int rx_filt_log_col_index;
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int rx_filt_log_col_sz;
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COMP *ch_symb_log;
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int ch_symb_log_r;
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int ch_symb_log_col_sz;
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float *rx_timing_log;
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int rx_timing_log_index;
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/* demodulated bits before diversity combination for test/instrumentation purposes */
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float rx_bits_lower[COHPSK_BITS_PER_FRAME];
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float rx_bits_upper[COHPSK_BITS_PER_FRAME];
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/* tx amplitude weights for each carrier for test/instrumentation */
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float carrier_ampl[COHPSK_NC*ND];
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/* Flag enabling simple freq est mode */
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int freq_est_mode_reduced;
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};
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void bits_to_qpsk_symbols(COMP tx_symb[][COHPSK_NC*COHPSK_ND], int tx_bits[], int nbits);
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void qpsk_symbols_to_bits(struct COHPSK *coh, float rx_bits[], COMP ct_symb_buf[][COHPSK_NC*COHPSK_ND]);
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void tx_filter_and_upconvert_coh(COMP tx_fdm[], int Nc, const COMP tx_symbols[],
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COMP tx_filter_memory[COHPSK_NC][COHPSK_NSYM],
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COMP phase_tx[], COMP freq[],
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COMP *fbb_phase, COMP fbb_rect);
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void fdm_downconvert_coh(COMP rx_baseband[COHPSK_NC][COHPSK_M+COHPSK_M/P], int Nc, COMP rx_fdm[], COMP phase_rx[], COMP freq[], int nin);
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void rx_filter_coh(COMP rx_filt[COHPSK_NC+1][P+1], int Nc, COMP rx_baseband[COHPSK_NC+1][COHPSK_M+COHPSK_M/P], COMP rx_filter_memory[COHPSK_NC+1][COHPSK_NFILTER], int nin);
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void frame_sync_fine_freq_est(struct COHPSK *coh, COMP ch_symb[][COHPSK_NC*COHPSK_ND], int sync, int *next_sync);
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void fine_freq_correct(struct COHPSK *coh, int sync, int next_sync);
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int sync_state_machine(struct COHPSK *coh, int sync, int next_sync);
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int cohpsk_fs_offset(COMP out[], COMP in[], int n, float sample_rate_ppm);
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#endif
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