Re-implements envelope detection on top of the rewritten Morse decoder.
Addresses PR #160 review feedback:
- Rebase: rebuilt on current upstream/main (lifecycle state machine)
- Gap thresholds: 2.0/5.0 for envelope only; goertzel keeps 2.6/6.0
- Frequency validation: max_mhz=1766 for envelope, 30 for goertzel
- Tests: EnvelopeDetector unit tests + envelope-mode decoder test
- Envelope uses direct magnitude threshold (no SNR/noise ref)
- Goertzel path completely unchanged
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Guard checkStatus() against in-flight stop to prevent status poller
from overriding stopping state and reconnecting SSE. Lower SNR floor
from 1.3 to 1.15 to accommodate weaker CW signals. Add SNR/noise_ref
to scope events and metrics for real-time threshold debugging.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Widen noise detector offset from ±100Hz to ±200Hz to reduce spectral
leakage into the noise reference, and scale threshold_multiplier for
SNR space (2.8 → 1.54) so real CW signals reliably trigger tone
detection instead of producing all-E's at 60 WPM.
Fix misleading "decoder startup" timeout message on stop requests and
increase stop timeout from 2.2s to 5s.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The previous magnitude-based threshold couldn't distinguish CW tone from
AGC-amplified inter-element silence — the Goertzel level stayed above
threshold permanently, preventing any tone OFF transitions and thus zero
character decodes.
Switch tone detection to use SNR (tone_mag / adjacent_band_noise_ref).
Both bands are equally amplified by AGC, so the ratio is gain-invariant.
Also replace the conditional noise_ref guard with unconditional blending
so the noise floor tracks actual ambient levels continuously.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Filter decoder-thread 'stopped' status events that race with the route
lifecycle, causing the frontend to drop back to idle on first start.
Pull noise floor upward using adjacent-frequency Goertzel reference when
warmup calibration runs before AGC converges, preventing permanent
tone-on with zero character decodes.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
BufferedReader.read(n) on non-interactive streams (Python 3.14) blocks
until the full n bytes accumulate, starving the decoder of real-time
PCM data. Use os.read() on the raw file descriptor instead, which
returns as soon as any data is available. Falls back to .read() for
file-like objects without fileno() (e.g. BytesIO in tests).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace select.select()+os.read() with a blocking reader thread feeding
a queue, matching pager's working pattern. The select() approach fails
to detect available data on Python 3.14's BufferedReader-wrapped pipes.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
rtl_fm prints device info, tuning, and errors to stderr but the morse
route only logged these server-side. Now stderr lines are forwarded to
the morse queue as info events, displayed in a compact diagnostic log
below the scope canvas. After 10s with no audio data, the scope text
escalates to prompt the user to check the SDR log.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace blocking rtl_stdout.read() with select()+os.read() so the
decoder thread emits diagnostic heartbeat scope events when rtl_fm
produces no PCM data (common in direct sampling mode). Add waiting-state
rendering in the scope canvas and hide the generic placeholder/status
bar for morse mode.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add automatic gain control (AGC) before Goertzel processing to normalize
quiet audio from direct sampling mode where the -g gain flag has no effect.
Fix broken adaptive threshold bootstrap by adding a 50-block warm-up phase
that collects magnitude statistics before seeding noise floor and signal peak.
Lower threshold ratio from 50% to 30% for better weak-CW sensitivity.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Enable direct sampling (-D 2) for RTL-SDR at HF frequencies below 24 MHz
so rtl_fm can actually receive CW signals. Add startup health check to
detect immediate rtl_fm failures. Push stopped status event from decoder
thread on EOF so the frontend auto-resets. Add frequency placeholder and
help text. Fix stop button silently swallowing errors.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
New signal mode for decoding Morse code (CW) transmissions via SDR.
Includes route blueprint, utility decoder, frontend UI, and tests.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
