ft8_lib/ft8/decode.h

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C
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#pragma once
#include <stdint.h>
namespace ft8 {
struct MagArray {
int num_blocks; // number of total blocks (symbols)
int num_bins; // number of FFT bins
int time_osr; // number of time subdivisions
int freq_osr; // number of frequency subdivisions
uint8_t * mag; // FFT magnitudes as [blocks][time_sub][freq_sub][num_bins]
};
struct Candidate {
int16_t score;
int16_t time_offset;
int16_t freq_offset;
uint8_t time_sub;
uint8_t freq_sub;
};
// Localize top N candidates in frequency and time according to their sync strength (looking at Costas symbols)
// We treat and organize the candidate list as a min-heap (empty initially).
int find_sync(const MagArray * power, const uint8_t *sync_map, int num_candidates, Candidate *heap, int min_score = 0);
// Compute log likelihood log(p(1) / p(0)) of 174 message bits
// for later use in soft-decision LDPC decoding
void extract_likelihood(const MagArray *power, const Candidate & cand, const uint8_t *code_map, float *log174);
}