period, frequency and pulse duration counted every sign change about a single
level, which is unusable on any real signal: the mid level is exactly where a
waveform moves fastest, so an interferer faster than the fundamental recrosses
it several times per true crossing. A 5 Hz sine with a 500 Hz tone at a tenth of
the amplitude read 79 crossings for 9, period=0.025622 against 0.2.
MeasureLevel gains a hysteresis band sized once in measure_set_level(): a tenth
of the window's peak-to-peak, clamped to half the room to the nearer extreme so
a threshold set near one stays usable. The band moves the edge decision only --
the sum/count split stays at the bare level, since that split is top/bottom and
has a documented exact reading. The bucket fast path tests the band and the
level separately rather than folding them, or it would refuse exactly the
buckets a crossing passes through: clean cost is unchanged at raw=0.1% and
1.41 ms a recompute.
tools/mock_udpstreamer.py gains --noise, defaulting to 0 so the exact probe
assertions still hold.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
