Two audit findings, both measured, both able to silently disable the feature.
A detection window landing in a keying gap used to collapse an established
shift to zero. CW is keyed, so gaps are normal: over 180 s of keyed audio at
1400 Hz, 11 of 90 detections saw no tone, and each one wiped the decode window
and left the next ~2 s buffered unshifted - outside the model's range and
therefore invisible to it. Absence of a tone is now absence of evidence and the
active shift is retained.
Hysteresis moved from shift space to tone space, anchored on the pitch that
produced the active shift. The old rule required a non-zero previous shift and
a needed shift, so it lapsed exactly where the jump is largest: at the 1200 Hz
edge one 12.5 Hz estimate hop flips between "inside" (shift 0) and "outside"
(a large shift). Measured 35 window drops in 60 detections for a 1205 Hz tone,
and 10 in 10 for a bare one-bin hop. A shift of zero is a real state, not the
absence of one. Slow drift still catches up, since the anchor bounds staleness
at the margin rather than letting it accumulate.
Detection prominence raised from 3.0 to 8.0. Pure noise peaks at 2.0-3.3 times
its own spectral mean, so 3.0 admitted roughly one noise window in five as a
"tone" - and a false tone is worse than none, since it moves a good signal out
of range. Keyed CW measures 47-51, so the gap is wide.
Shifted output is clamped to the +/-1.0 range the spectrogram assumes. The
Hilbert kernel's L1 gain is 2.51, so mixing overshoots: a full-scale square
wave measured 2.35 and even a plain sine 1.05.
The detection pool moved to core:domain as CwDetectionPool so its ring
behaviour can be tested directly - mutation testing showed the previous private
implementation was unreachable from any test. Its chronological-order contract
now has 11 tests driving the real class.
Removed the write-only detectedToneHz field.
74 CW tests pass, golden vectors included.
mckero
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