Remove rig_id filtering from dispatchDecodeMessage and dispatchDecodeBatch
so that decode data from all rigs (including remote/non-primary) flows into
the map. Also remove the rig_filter query param from decode history fetch
so all history is loaded. The existing map rig filter dropdown handles
visibility filtering via marker.__trxRigIds.
https://claude.ai/code/session_01GGvdXKdEbRBnJa2BjAQuVB
Signed-off-by: Claude <noreply@anthropic.com>
The noise floor subtraction was over-aggressive: the bandwidth ratio
scaling between the 67 kHz baseband probe and the IQ domain amplified
the noise estimate excessively, causing weak stations to be subtracted
to nothing. The pilot-referenced correction only worked for stereo
stations.
Strip the signal strength path back to what actually works universally:
mean IQ envelope power with asymmetric attack/decay smoothing. This
always produces a reading for any FM signal — mono, stereo, with or
without RDS.
The baseband noise probe, CNR estimation, and pilot metrics remain in
the WfmStereoDecoder for their existing uses (RDS quality weighting,
CCI/ACI estimation) but no longer feed into the S-meter.
https://claude.ai/code/session_017URSDqSJ8TyZpDhV2vKZUe
Signed-off-by: Claude <noreply@anthropic.com>
Replace the simple IQ power averaging with a proper WFM signal
strength measurement algorithm based on established RF engineering
practice:
1. Asymmetric attack/decay smoothing (τ_attack=2ms, τ_decay=300ms)
per IARU Region 1 Technical Recommendation R.1 for professional
S-meter behaviour. Fast attack catches signal increases
immediately; slow decay provides stable, readable meter movement.
2. Baseband noise floor estimation via a 67 kHz probe in the
demodulated FM baseband. FM demodulation noise follows an f²
spectral shape, so energy above the useful baseband (audio +
RDS ≤ 57 kHz) is dominated by channel noise and independent of
program content. Subtracting this noise estimate in the linear
domain reveals the carrier-only power, preventing the meter from
reading the noise floor on empty/weak channels.
3. Pilot-referenced quality correction. The 19 kHz stereo pilot
has a known fixed amplitude at the transmitter (±7.5 kHz
deviation, 10% of ±75 kHz). Near the FM threshold (~10 dB CNR)
where noise dominates the IQ reading, the pilot tone power
provides an independent quality-weighted correction. The blend
factor scales from 0.3 at low CNR down to 0 at high CNR where
the raw IQ measurement is already accurate.
4. CNR estimation from the ratio of total baseband power to the
above-band noise probe, enabling adaptive pilot correction and
providing a signal quality metric for future use.
https://claude.ai/code/session_017URSDqSJ8TyZpDhV2vKZUe
Signed-off-by: Claude <noreply@anthropic.com>
Change RigRxStatus.sig from i32 to f64 and add get_signal_strength_db
to RigCat trait so SDR backends can bypass the coarse 0..15 quantisation.
Compensate for decimation processing gain so the meter matches the
spectrum peak. Display with one decimal place in all units.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Smooth envelope power (I²+Q²) instead of filtering I/Q components
separately — eliminates ~6 dB modulation-dependent fluctuation caused
by FM carrier rotation in the IQ plane. Reset signal strength on
frequency change. Reduce SDR poll interval from 500ms to 100ms.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
The previous carrier power IIR filtered |IQ|² (power), which only smoothed
temporal fluctuations but still integrated noise across the full 180 kHz WFM
channel bandwidth. This caused background noise to read ~-78 dBFS instead of
the expected ~-110 dBFS (~32 dB too high ≈ 10·log₁₀(180kHz/500Hz)).
Move the single-pole IIR lowpass to the IQ domain (filter I and Q separately
at ~500 Hz cutoff), then compute power from the filtered output. This rejects
out-of-band noise before the power measurement, so the meter reads true
carrier level rather than total wideband noise.
https://claude.ai/code/session_01W4WPMB2Lg3hgaY6opsk25f
Signed-off-by: Claude <noreply@anthropic.com>
Replace peak |IQ|² measurement with a per-sample single-pole IIR lowpass
on the instantaneous power (~500 Hz cutoff). FM has constant envelope so
the IIR converges to the true carrier power A², rejecting wideband noise
that previously inflated the peak reading and masked actual signal level.
Other modes keep the existing peak + EMA approach.
https://claude.ai/code/session_01X6tedMVpjX3DEqLFDBR7FK
Signed-off-by: Claude <noreply@anthropic.com>
Increase sig-strength-display min-width to 7.5rem so the field no longer
resizes when the value switches between two-digit and three-digit numbers.
Reposition the fast BW overlay immediately when bandwidth changes arrive
via SSE, and force-display on bookmark apply so freq+bw render atomically
instead of the BW bars wiggling from a stale intermediate state.
https://claude.ai/code/session_01R2XBFEBL8CrsTx5inu25MA
Signed-off-by: Claude <noreply@anthropic.com>
SSE status updates called applyLocalTunedFrequency with forceDisplay=true,
clearing the freqDirty flag on every update and overwriting user input mid-
typing. Remove forceDisplay from SSE path so the dirty flag is respected.
Skip applyLocalTunedFrequency entirely when frequency hasn't changed to
avoid redundant spectrum redraws and overlay repositioning on every SSE
frame. Only trigger scheduleSpectrumDraw when frequency actually changes.
Add blur and Escape handlers on frequency inputs to cleanly exit editing
mode when the user abandons input.
https://claude.ai/code/session_01H2VMATj29FPgR64t9YMdSR
Signed-off-by: Claude <noreply@anthropic.com>
The closed-loop Gardner Timing Error Detector was causing decoder
freezes under real-world conditions. Remove all TED state and logic,
reverting to the simpler open-loop fixed clock_inc approach. The
8-candidate parallel architecture already provides adequate timing
coverage via phase offsets without needing closed-loop tracking.
All other improvements (adaptive Costas bandwidth, syndrome-based OSD,
OSD(3/4), PI LLR accumulation) are retained.
https://claude.ai/code/session_01FsK5hZWGpAaaCpmWupN5AD
Signed-off-by: Claude <noreply@anthropic.com>
The 8th-order (4×biquad) RDS bandpass at Q=5 per stage produced a
composite −3 dB bandwidth of ±2480 Hz, but the steep 8th-order roll-off
tapered the RDS signal edges (±1544 Hz at α=0.30) by −1.2 dB. This
distorted the RRC matched filter's expected flat spectrum, causing ISI
and degrading soft-decision confidence — directly hurting PS/RT decode
on weak signals.
Q=3.5 widens the composite passband to ±3560 Hz, reducing band-edge
attenuation to −0.59 dB while still providing ≈−4 dB rejection at the
stereo difference signal edge (53 kHz) and steep 8th-order far-out
roll-off.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
https://claude.ai/code/session_01Sw9esAuic8KHP1t8nZgvH2
Signed-off-by: Claude <noreply@anthropic.com>
The span-5 reduction passed synthetic tests because both the TX and RX
filters used the same truncated pulse shape (perfect matched filtering).
On real signals, the transmitter uses a full RRC pulse, and our truncated
RX filter couldn't match it — the weaker stopband rejection (~25% less
than pre-TED at α=0.30) allowed adjacent-channel interference through,
degrading soft confidence values and block decode rate, which caused
poor PS accumulation.
Span 10 at α=0.30 gives 50% better stopband rejection than the pre-TED
α=0.50/span=4 configuration, at the cost of 2048 vs 1024 FFT size.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
https://claude.ai/code/session_01Sw9esAuic8KHP1t8nZgvH2
Signed-off-by: Claude <noreply@anthropic.com>
Three root causes for the post-TED decode quality regression:
1. OSD(4) at cost ceiling 0.60 produced excessive false positives at
marginal SNR. Tightened to OSD(2)/0.45 baseline, OSD(3)/0.50 only
after 2+ successful groups.
2. Gardner TED activated after just 1 group (score >= 1), but a single
false OSD match could trigger timing adjustments that injected jitter
into soft values. Raised lock gate to score >= 3 so the TED only
engages after the candidate has proven itself on a real signal.
3. RRC filter span of 10 chips doubled FFT size to 2048 with negligible
sensitivity gain over span 5 at α=0.30 (sidelobes beyond ±2.5 chips
contribute <5% energy). Reduced to span 5 → FFT 1024, matching
pre-TED efficiency.
Additional optimizations (no quality impact):
- Syndrome-based OSD: replaces per-trial CRC recomputation with a single
XOR per trial (CRC linearity), and sorts bit positions by ascending
soft confidence so inner loops break early instead of continuing.
- Pre-allocated FFT scratch buffer: eliminates ~234 heap allocations/sec
in the overlap-save convolution.
- PI_ACC_THRESHOLD reduced from 8 to 5 for faster acquisition while
retaining reliable majority voting.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
https://claude.ai/code/session_01Sw9esAuic8KHP1t8nZgvH2
Signed-off-by: Claude <noreply@anthropic.com>
Replace the DC-component approach (which underreads FM due to carrier deviation) with peak |s|² on the filtered+decimated IQ before AGC is applied. Works correctly for both constant-envelope FM and narrowband modes.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
EMA (α=0.4) smooths the carrier power estimate across DSP blocks. Custom PartialEq on VchanRdsEntry excludes signal_db so rapidly-changing levels do not trigger main state SSE updates that overwrite the frequency input.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Use the DC component of the baseband-mixed IQ (before LPF/decimation) as a narrow-band carrier power estimate. This correlates with the spectrum FFT peak instead of measuring wideband channel power which inflates the reading for WFM.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Add a new "Sig Strength" display field in the freq row that shows
the measured signal strength. Clicking the field cycles through
three units: dBFS (default), dBf, and dBm. The selected unit is
persisted in localStorage.
https://claude.ai/code/session_01EvRV8UgsVtbrcH4t2hmFBF
Signed-off-by: Claude <noreply@anthropic.com>
The Gardner TED (Tech 11) caused PI instability and worse weak-signal
pickup due to three issues:
1. Loop gains too aggressive: noise×noise error products at low SNR
injected sub-chip jitter that degraded OSD soft confidence and PI
LLR accumulation. Reduced Kp from 4e-4→1.5e-4, Ki from 8e-8→2e-8
(loop BW 0.11→0.053 Hz).
2. TED active during acquisition: before any group is decoded, the
error signal is unreliable. Now lock-gated (score >= 1) so the
TED only engages after the first successful group decode, when
timing is already close. During acquisition, the 8-candidate
architecture with fixed clocks provides adequate timing coverage.
3. Slow power estimate convergence: ted_power_est took ~420 ms to
settle (0.999 alpha), causing the TED to over-steer during startup.
Now uses 0.995 alpha (~84 ms convergence).
Additionally, when TED is gated off, the integrator decays toward zero
so stale corrections from a previous strong-signal period don't persist.
https://claude.ai/code/session_01KcVUcQQXrFyFA9NEjLhr9J
Signed-off-by: Claude <noreply@anthropic.com>
ACI: the hard limiter in channel.rs normalised IQ samples to unit
magnitude *before* the CMA equalizer, making the signal perfectly
constant-modulus so the CMA never adapted and tap deviation stayed
at zero. Fix by moving the hard limiter inside process_iq (after
the CMA) and replacing the CMA-based metric with IQ envelope
coefficient of variation, computed on the raw samples.
CCI: the pilot coherence has a theoretical maximum of π/4 ≈ 0.785
(not 1.0), so coherence_penalty was always ~0.215 even for a clean
signal. The Q/I ratio also depended on the arbitrary NCO-pilot
phase offset rather than actual interference. Fix by normalising
coherence by its theoretical max and dropping the phase-dependent
Q/I ratio. Gate CCI on pilot detection so mono signals read 0%.
https://claude.ai/code/session_01PUXWNMRGfrWYH56k2DLmen
Signed-off-by: Claude <noreply@anthropic.com>
After completing a group (Block D), the decoder dropped lock and
reverted to search mode which only uses hard CRC. On weak signals,
Block A frequently has bit errors that OSD could correct but hard
decode cannot, causing the decoder to freeze after 2-3 successful
groups. Stay locked with ExpectBlock::A so the next Block A benefits
from OSD soft decoding.
https://claude.ai/code/session_015Ds9dxpeyFimYHySBuzbFw
Signed-off-by: Claude <noreply@anthropic.com>
Estimate Co-Channel Interference (CCI) from pilot tone quadrature
leakage and coherence degradation. Estimate Adjacent Channel
Interference (ACI) from CMA equalizer tap deviation from identity.
Both metrics (0-100 scale) are surfaced through RigFilterState and
displayed as colour-coded bars in the WFM control panel.
The RDS decoder quality parameter is now adaptively penalised when
CCI/ACI levels are elevated, reducing block-error rate under
interference conditions.
https://claude.ai/code/session_016EKzep42RCvE4GxvvRaCwu
Signed-off-by: Claude <noreply@anthropic.com>
If the incumbent candidate has not produced a state update in 2 seconds,
clear its score advantage so any candidate can take over. This prevents
the decoder from "freezing" on stale data when the incumbent's timing or
carrier tracking degrades — particularly important for dynamic PS where
the station rotates program service text.
Signed-off-by: Claude <noreply@anthropic.com>
https://claude.ai/code/session_0136sPdLUpYgvskrzbi2Epkv
Signed-off-by: Claude <noreply@anthropic.com>
Fix Gardner TED loop structure bug (type-3 → type-2 PLL) and tune
gains for ζ=0.707 damping. Add adaptive Costas loop bandwidth that
narrows from ~22 Hz to ~5.5 Hz once carrier is locked, reducing phase
noise at low SNR. Narrow RRC matched filter (α=0.30, span=10 chips)
for ~0.6 dB noise BW gain. Add OSD(4) for locked-mode blocks after
first successful group, and increase PI accumulation threshold to 8.
TED bug details: the original code used `clock_inc += correction`
which added the full integrator value at every chip, creating an
extra integration (type-3 loop) that is unconditionally unstable.
Fixed to `clock_inc = nominal + correction` (standard type-2 PLL).
Gains retuned: Kp=4e-4, Ki=8e-8 for ζ≈0.707 and loop BW≈0.11 Hz.
Signed-off-by: Claude <noreply@anthropic.com>
https://claude.ai/code/session_0136sPdLUpYgvskrzbi2Epkv
Signed-off-by: Claude <noreply@anthropic.com>
- RRC span 4→6 chips: better ISI rejection and pulse energy capture
- PI_ACC_THRESHOLD 3→5: more Block A votes before committing PI at weak signal
- OSD(3): add C(26,3)=2600 triple-bit search under same cost gate as OSD(2)
- Tech 11 Gardner TED: closed-loop symbol timing PI loop per Candidate;
replaces open-loop NCO with mid-chip capture, power-normalised error signal,
anti-windup integrator, and ±1% pull-in range (±23.75 Hz at 2375 chips/s)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
The Auto button now toggles between Off and Auto states. Default is Off.
First click sets squelch to noise floor + 6 dB; second click resets to
Open (0%). Button shows active state with green highlight when engaged.
https://claude.ai/code/session_01TDQyrZiPKfWGATVWPsLmHT
Signed-off-by: Claude <noreply@anthropic.com>
Add an "Auto" button next to the SQL slider that sets the squelch
threshold to the current noise floor (estimated from spectrum bins)
plus a 6 dB margin. Uses the existing estimateNoiseFloorDb() heuristic.
https://claude.ai/code/session_01TDQyrZiPKfWGATVWPsLmHT
Signed-off-by: Claude <noreply@anthropic.com>
Add OSD_MAX_FLIP_COST (0.45) to reject OSD corrections where the flipped
bits had high confidence — a strong false-decode indicator. Genuine errors
at 9-10 dB SNR have cost ≲0.3; noise matches cost 0.6-1.2.
Add PI consistency gate in process_group: reject groups whose Block A PI
differs from the candidate's established PI, preventing noise from
polluting accumulated PS/RT/PTYN text fields.
Raise PI_ACC_THRESHOLD from 2 to 3 for stronger PI voting.
Extend noise rejection test from 0.5s to 2s. Add 9 dB SNR sensitivity
test (all 16 tests pass).
https://claude.ai/code/session_01GYax4BQ9ZV9ZZfMjmmzgbh
Signed-off-by: Claude <noreply@anthropic.com>
The WSPR decoder was producing many false positive decodes due to
several overly permissive thresholds that allowed noise to reach the
Fano sequential decoder, which could then converge on random data:
- Raise normalized sync score threshold from 0.10 to 0.20 to reject
noise candidates before attempting expensive Fano decoding
- Add minimum SNR gate (-20 dB) to skip candidates where the signal
is indistinguishable from noise
- Return and check the Fano decoder's cumulative path metric, rejecting
low-confidence decodes (metric < 20) that are likely noise artifacts
- Raise RMS threshold from 0.0005 to 0.005 to reject near-silent audio
- Add near-frequency deduplication to prevent the same signal decoded
at slightly different (freq, dt) offsets from appearing multiple times
- Add noise-only regression test to verify no false positives on random
input
https://claude.ai/code/session_01HTBoEsD1hp99TiYMSaHMVG
Signed-off-by: Claude <noreply@anthropic.com>
The `chips_to_rds_signal` test helper was generating rectangular chip
pulses, but the receiver expects RRC-shaped transmit pulses so that
RRC(tx) × RRC(rx) = raised cosine with zero ISI. The rectangular
pulses caused ISI that drifted the symbol clock sampling point,
consistently skipping PS segment 2 in the end-to-end test.
Replace rectangular pulses with an impulse train convolved with the
same RRC taps used by the receiver. All 15 tests now pass including
`end_to_end_clean_signal_decodes_ps`.
https://claude.ai/code/session_01N2UcGaLDzYiM3gNrZ6kFBj
Signed-off-by: Claude <noreply@anthropic.com>
- RRC_ALPHA 0.75→0.50: narrower noise BW, ~0.6 dB SNR gain
- COSTAS_KI 3.5e-7: maintain ζ≈0.68 (1e-6 caused loop instability)
- Soft confidence: use biphase_i.abs() instead of full vector magnitude
so OSD confidence is aligned with bit-decision sign; suppresses
false groups under noise with residual Costas phase error
- OSD(2) in locked mode: corrects ≤2-bit errors after block sync
- Search mode: hard decode only for Block A; OSD(1) in search yielded
~13% false Block A rate per bit, letting wrong clock candidates
accumulate false groups as fast as the correct candidate
- Incumbent candidate tracking (best_candidate_idx): the winning
candidate updates best_state at equal score; challengers need strictly
higher score; best_score tracks incumbent even on no-state-change
groups so challengers can't leapfrog on a single false group
- blocks_to_chips: add NRZI (NRZ-Mark) pre-encoding so the differential
biphase decoder recovers actual data bits rather than XOR-of-pairs
- Add blocks_to_chips_round_trips_all_groups test: verifies all 16 blocks
across 4 PS segments round-trip correctly without BPSK modulation
[fix](trx-backend-soapysdr): lower pilot lock threshold for weak-signal RDS
- PILOT_LOCK_THRESHOLD 0.25→0.20, add PILOT_LOCK_ONSET=0.30 constant
- Pilot reference engages at coherence ≥0.36 (was ≥0.45)
WIP: end_to_end_clean_signal_decodes_ps still failing (13/15 pass).
Decoder skips segment 2 due to ISI from rectangular test chips through
RRC receive filter. chips_to_rds_signal needs RRC pulse shaping.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Lower PILOT_LOCK_THRESHOLD 0.5 -> 0.25 so the accurate 57 kHz pilot-derived
carrier reference is handed to the RDS decoder even with a weaker pilot tone.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
- Add single-bit flip fallback in search mode (push_bit_soft) so Block A
can be acquired with one bit error, matching locked-mode OSD(1) behaviour
- Lower MIN_PUBLISH_QUALITY 0.38 -> 0.20 for earlier publish on noisy signals
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
- Replace FirFilter (ring-buffer FIR) with FftRrcFilter using overlap-save
FFT convolution; I and Q are processed together as a single complex FFT,
halving filter cost (~10x fewer operations than direct convolution)
- Reduce PHASE_CANDIDATES 16 -> 8 (reasonable, double the original)
- Lower MIN_PUBLISH_QUALITY 0.55 -> 0.38 (more permissive acquisition)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
The IQ prefilter cutoff was audio_bandwidth_hz/2, so any setting below
~120 kHz would cut off the 57 kHz RDS subcarrier before FM demod.
- Clamp IQ prefilter cutoff to >= 60 kHz for WFM in both new() and
rebuild_filters() — audio quality is unaffected since WfmStereoDecoder
applies its own 18 kHz lowpass internally
- Ensure pipeline target rate >= 120 kHz for WFM so the decimated IQ
sample rate can represent the 60 kHz cutoff
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
- Downgrade OSD from distance-2 to distance-1 (removes 325-iteration
double-bit flip loop per block, main source of both false positives
and excess CPU)
- Reduce phase candidates from 8 to 4 (halves per-sample work)
- Raise MIN_PUBLISH_QUALITY from 0.45 to 0.65 (requires stronger
signal confidence before emitting decoded state)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Track per-rig server connection state in `rig_server_connected` so that when
one trx-server drops, only the rig(s) it serves are marked disconnected. Other
rigs with active connections remain fully interactive. The SSE `server_connected`
field is now resolved from the per-rig map for the session's active rig, falling
back to the global flag for backward compatibility.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Tech 1: replace one-pole baseband LPF with FIR RRC matched filter
(alpha=0.75, 4-chip span) — largest single measured improvement per
empirical comparison (gr-rds RRC vs plain FIR: 32/38 vs 18/38 stations).
Tech 2: 19 kHz pilot x3 -> 57 kHz coherent carrier reference via the
triple-angle formula; fed from the WFM pilot Costas PLL when
pilot_lock_level > 0.5, clearing to NCO fallback otherwise.
Tech 3/7/8: OSD(2) soft-decision block decoder replaces hard CRC check.
Per-bit soft magnitudes accumulated in Candidate::block_soft[26].
decode_block_soft() searches Hamming distance 0/1/2 (352 trials total)
and returns the minimum Euclidean-cost valid codeword; ~2-3 dB gain.
Tech 4: 8th-order 57 kHz BPF (4 cascaded biquads at Q=5) in wfm.rs
replaces the previous single Q=10 biquad; ~6x steeper ACI stopband.
Tech 5: Costas loop with tanh soft phase detector drives the RDS carrier
NCO when no pilot reference is available (P+I, B_L ~20 Hz).
Tech 6: Block A PI field LLR accumulation — signed per-bit LLR summed
over 3 independent Block A observations before committing the PI value,
correcting weak-signal false locks without delaying strong-signal lock.
Tech 9: 8-tap complex CMA blind equalizer applied to IQ samples before
FM discrimination; constant-modulus error (|y|^2 - R^2) drives tap
adaptation without a training sequence, suppressing adjacent-channel
interference at the source.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Use saturating CAS loop in adjust_total_count to prevent AtomicUsize underflow, and cap history estimate at 500k entries.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>
Claude
sjg