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