1) Preamble · prime length
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Auto: 31→mseq, 47→Legendre
Corr: —
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Autocorrelation shown as max sidelobe (periodic). ±1 symbols recommended for BPSK audio plants.
2) Control Header → Golay(24,12,8)
Raw 12‑bit header (v|topo|tid|lane)
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Golay(24,12,8) codeword (23b Golay + even parity)
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We implement the standard (23,12,7) Golay by polynomial division, then append a single even parity bit to form (24,12,8).
3) Descriptor → CRC‑16 → RS(31,19) over GF(32)
Descriptor bits (pre‑CRC)
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CRC‑16/CCITT (poly 0x1021), appended MSB→LSB
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Data symbols (5‑bit, padded to 19)
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Codeword (31 symbols) · hex
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GF(32) uses primitive polynomial x⁵+x²+1 and generator roots α¹…α¹². Data shorter than 19 symbols is zero‑padded.
4) Assembly (pre‑/post‑ECC)
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Use pre‑ECC bits when testing symbolization; use post‑ECC when planting full frames in controlled channels.