spectra-fourier: v12 — the Coding lab (convolutional codes + Viterbi + coding gain)#588
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…+ coding gain)
Adds a complete forward-error-correction pillar (the 17th mode) on top of the
Modem's channel:
- src/lib/fec.ts — from-scratch convolutional encoder over an octal-generator
rate-1/n trellis (five textbook codes, K=3 (7,5) … K=7 (171,133) and the
rate-1/3 (171,133,165)); a single add-compare-select Viterbi core with hard
(Hamming) and soft (squared-Euclidean) branch metrics, full traceback, and
exposed per-step survivor metrics + back pointers for the animation;
rate-compatible puncturing (2/3, 3/4, 5/6) with erasure de-puncturing; a
weight-bounded DP that enumerates every first-return-to-zero error event into
the code's distance spectrum {d, a_d, c_d}, giving d_free and the soft/hard
union bounds; and an end-to-end Monte-Carlo coded link.
- src/modes/Coding.tsx — three tabs: a live animated Viterbi trellis (survivor
sweep, per-node metrics, ML path vs true path), the coding-gain plot
(uncoded/hard/soft measured dots + union bounds + distance-spectrum bars +
gain readouts), and a message demo (same text through the same noise, shredded
uncoded vs. perfectly repaired coded, character-diffed). All deep-linkable.
- 8 new self-tests (51-58): published d_free for all five codes + the exact
(7,5) spectrum, noiseless hard/soft round-trips, single-error correction,
soft <= hard < uncoded with measured <= union bound, a >=10x soft coding gain,
exact puncture rates + de-puncture round-trip, a punctured link beating its
channel BER, and text<->bits round-trip. All 90 self-tests green.
The (171,133) trellis re-derives d_free = 10 with a_10 = 11 (the published
value). lint + tsc + vite build pass; verified live in a headless browser.
No coding libraries — every generator, trellis, metric and bound is hand-built.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B7NSkgG4x7CkmmwMKPVzRi
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Substantially improves the Claude-authored Spectra — Fourier Lab (
projects/spectra-fourier-7k9d) by adding a complete, from-scratch forward-error-correction pillar — its 17th mode, Coding — built on the existing Modem channel. Every generator, trellis, decoder metric and error bound is hand-written; no coding libraries.What's new
src/lib/fec.ts— the FEC engine{d, aᵈ, cᵈ}, enumerated by a weight-bounded DP over first-return-to-zero error events, givingd_freeand the closed-form soft/hard union bounds.src/modes/Coding.tsx— the UI (three deep-linkable tabs)Verification
d_freefor all five codes + the exact (7,5) spectrum, noiseless hard/soft round-trips, single-error correction,soft ≤ hard < uncodedwithmeasured ≤ union bound, a ≥10× soft coding gain, exact puncture rates + de-puncture round-trip, a punctured link beating its channel BER, and text↔bits round-trips.node scripts/verify-project.mjs spectra-fourier-7k9dpasses (scope + conformance +pnpm lint+pnpm build); verified live in a headless browser (all three tabs render, zero console errors, a 2 dB message repaired from 5 uncoded bit errors to 0).All changes live inside the single
projects/spectra-fourier-7k9d/folder (Golden Rule).JOURNAL.md,project.jsonand the About page are updated; the journal adds a v12 plan, a session-log entry, and a fresh backlog (BCJR/MAP, turbo codes, RSC, QAM-LLR coding, traceback-depth, sequential decoding, block codes, exact punctured spectra, interleaving, an LDPC teaser).🤖 Generated with Claude Code
https://claude.ai/code/session_01B7NSkgG4x7CkmmwMKPVzRi
Generated by Claude Code