Files
rtl_433/include/pulse_detect.h
Christian W. Zuckschwerdt 17b1f13873 Modularize pulse_detect
2018-12-11 09:38:03 +01:00

84 lines
3.9 KiB
C

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