95 lines
4.4 KiB
C
95 lines
4.4 KiB
C
/** @file
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Pulse detection functions.
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Copyright (C) 2015 Tommy Vestermark
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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 General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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*/
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#ifndef INCLUDE_PULSE_DETECT_H_
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#define INCLUDE_PULSE_DETECT_H_
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#include <stdint.h>
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#include <stdio.h>
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#include "r_util.h"
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#define PD_MAX_PULSES 1200 // Maximum number of pulses before forcing End Of Package
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#define PD_MIN_PULSES 16 // Minimum number of pulses before declaring a proper package
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#define PD_MIN_PULSE_SAMPLES 10 // Minimum number of samples in a pulse for proper detection
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#define PD_MIN_GAP_MS 10 // Minimum gap size in milliseconds to exceed to declare End Of Package
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#define PD_MAX_GAP_MS 100 // Maximum gap size in milliseconds to exceed to declare End Of Package
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#define PD_MAX_GAP_RATIO 10 // Ratio gap/pulse width to exceed to declare End Of Package (heuristic)
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#define PD_MAX_PULSE_MS 100 // Pulse width in ms to exceed to declare End Of Package (e.g. for non OOK packages)
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/// Data for a compact representation of generic pulse train.
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typedef struct {
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uint64_t offset; ///< Offset to first pulse in number of samples from start of stream.
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uint32_t sample_rate; ///< Sample rate the pulses are recorded with.
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unsigned start_ago; ///< Start of first pulse in number of samples ago.
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unsigned end_ago; ///< End of last pulse in number of samples ago.
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unsigned int num_pulses;
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int pulse[PD_MAX_PULSES]; ///< Width of pulses (high) in number of samples.
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int gap[PD_MAX_PULSES]; ///< Width of gaps between pulses (low) in number of samples.
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int ook_low_estimate; ///< Estimate for the OOK low level (base noise level) at beginning of package.
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int ook_high_estimate; ///< Estimate for the OOK high level at end of package.
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int fsk_f1_est; ///< Estimate for the F1 frequency for FSK.
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int fsk_f2_est; ///< Estimate for the F2 frequency for FSK.
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float freq1_hz;
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float freq2_hz;
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float rssi_db;
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float snr_db;
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float noise_db;
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} pulse_data_t;
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typedef struct pulse_detect pulse_detect_t;
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/// Clear the content of a pulse_data_t structure.
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void pulse_data_clear(pulse_data_t *data);
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/// Print the content of a pulse_data_t structure (for debug).
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void pulse_data_print(pulse_data_t const *data);
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/// Dump the content of a pulse_data_t structure as raw binary.
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void pulse_data_dump_raw(uint8_t *buf, unsigned len, uint64_t buf_offset, pulse_data_t const *data, uint8_t bits);
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/// Print a header for the VCD format.
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void pulse_data_print_vcd_header(FILE *file, uint32_t sample_rate);
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/// Print the content of a pulse_data_t structure in VCD format.
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void pulse_data_print_vcd(FILE *file, pulse_data_t const *data, int ch_id);
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/// Read the next pulse_data_t structure from OOK text.
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void pulse_data_load(FILE *file, pulse_data_t *data);
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/// Print a header for the OOK text format.
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void pulse_data_print_pulse_header(FILE *file);
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/// Print the content of a pulse_data_t structure as OOK text.
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void pulse_data_dump(FILE *file, pulse_data_t *data);
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pulse_detect_t *pulse_detect_create(void);
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void pulse_detect_free(pulse_detect_t *pulse_detect);
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/// Demodulate On/Off Keying (OOK) and Frequency Shift Keying (FSK) from an envelope signal.
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///
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/// Function is stateful and can be called with chunks of input data.
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/// @param envelope_data: Samples with amplitude envelope of carrier
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/// @param fm_data: Samples with frequency offset from center frequency
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/// @param len: Number of samples in input buffers
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/// @param samp_rate: Sample rate in samples per second
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/// @param *pulses: Will return a pulse_data_t structure
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/// @param *fsk_pulses: Will return a pulse_data_t structure for FSK demodulated data
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/// @return 0 if all input sample data is processed
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/// @return 1 if OOK package is detected (but all sample data is still not completely processed)
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/// @return 2 if FSK package is detected (but all sample data is still not completely processed)
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int pulse_detect_package(pulse_detect_t *pulse_detect, int16_t const *envelope_data, int16_t const *fm_data, int len, int16_t level_limit, uint32_t samp_rate, uint64_t sample_offset, pulse_data_t *pulses, pulse_data_t *fsk_pulses);
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/// Analyze and print result.
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void pulse_analyzer(pulse_data_t *data);
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#endif /* INCLUDE_PULSE_DETECT_H_ */
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