107 lines
4.6 KiB
C
107 lines
4.6 KiB
C
/* ssql.h
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This file is part of a program that implements a Software-Defined Radio.
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Copyright (C) 2023 Warren Pratt, NR0V
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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The author can be reached by email at
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warren@pratt.one
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*/
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#ifndef _ssql_h
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#define _ssql_h
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typedef struct _ftov // Frequency to Voltage Converter
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{
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int run; // 0 => don't run; 1 => run
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int size; // buffer size
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int rate; // sample-rate
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int rsize; // rate * time_to_fill_ring, e.g., 48K/s * 50ms = 2400
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double fmax; // frequency (Hz) for full output, e.g., 2000 (Hz)
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double* in; // pointer to the intput buffer for ftov
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double* out; // pointer to the output buffer for ftov
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int* ring; // pointer to the base of the ring
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int rptr; // index into the ring
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double inlast; // holds last sample from previous buffer
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int rcount; // count of zero-crossings currently in the ring
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double div; // divisor for 'rcount' to produce output of 1.0 at 'fmax'
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double eps; // minimum input change to count as a signal edge transition
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} ftov, *FTOV;
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typedef struct _ssql // Syllabic Squelch
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{
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int run; // 0 if squelch system is OFF; 1 if it's ON
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int size; // size of input/output buffers
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double* in; // squelch input signal buffer
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double* out; // squelch output signal buffer
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int rate; // sample rate
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int state; // state machine control
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int count; // count variable for raised cosine transitions
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double tup; // time for turn-on transition
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double tdown; // time for turn-off transition
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int ntup; // number of samples for turn-on transition
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int ntdown; // number of samples for turn-off transition
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double* cup; // coefficients for up-slew
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double* cdown; // coefficients for down-slew
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double muted_gain; // audio gain while muted; 0.0 for complete silence
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double* b1; // buffer to hold output of dc-block function
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double* ibuff; // buffer containing only 'I' component
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double* ftovbuff; // buffer containing output of f to v converter
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double* lpbuff; // buffer containing output of low-pass filter
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int* wdbuff; // buffer containing output of window detector
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CBL dcbl; // pointer to DC Blocker data structure
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FTOV cvtr; // pointer to F to V Converter data structure
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BQLP filt; // pointer to Bi-Quad Low-Pass Filter data structure
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int ftov_rsize; // ring size for f_to_v converter
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double ftov_fmax; // fmax for f_to_v converter
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// window detector
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double wdtau; // window detector time constant
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double wdmult; // window detector time constant multiplier
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double wdaverage; // average signal value
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double wthresh; // window threshold above/below average
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// trigger
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double tr_thresh; // trigger threshold: 100K/(100K+22K)=0.8197
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double tr_tau_unmute; // trigger unmute time-constant: (100K||220K)*10uF = 0.6875
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double tr_ss_unmute; // trigger steady-state level for unmute: 100K/(100K+220K)=0.3125
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double tr_tau_mute; // trigger mute time-constant: 220K*10uF = 2.2
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double tr_ss_mute; // trigger steady-state level for mute: 1.0
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double tr_voltage; // trigger voltage
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double mute_mult; // multiplier for successive voltage calcs when muted
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double unmute_mult; // multiplier for successive voltage calcs when unmuted
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int* tr_signal; // trigger signal, 0 or 1
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} ssql, * SSQL;
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extern SSQL create_ssql (int run, int size, double* in, double* out, int rate, double tup, double tdown,
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double muted_gain, double tau_mute, double tau_unmute, double wthresh, double tr_thresh, int rsize, double fmax);
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extern void destroy_ssql (SSQL a);
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extern void flush_ssql (SSQL a);
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extern void xssql (SSQL a);
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extern void setBuffers_ssql (SSQL a, double* in, double* out);
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extern void setSamplerate_ssql (SSQL a, int rate);
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extern void setSize_ssql (SSQL a, int size);
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#endif
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