sjg
c10b5faef4
The old IQ noise blanker tracked a fast running RMS and, on a threshold crossing, replaced the sample with the last clean one. That hard sample-and-hold is a step discontinuity: it splatters energy back across the wideband passband, so after the narrow channel filter it often sounded worse than the noise it removed — especially on SSB, CW and digital. It also had no look-ahead (the impulse leading edge leaked through before the fast RMS reacted), blanked only single samples, and used a fixed 1/128 time constant that did not scale with capture rate. Redesign the blanker around accepted wideband-NB practice and add profiles matched to the interference source: - Noise-floor tracker updated only from clean samples and frozen while blanking, so a burst cannot desensitise detection. - Detection on instantaneous power vs threshold² × noise floor. - Look-ahead delay line so the gate closes *before* the impulse reaches the output, removing the leading edge. - Raised-cosine tapered gate (ramp 1→0→1) instead of a hard hold, which minimises blanker splatter. - Windowed blanking that re-arms on every detected sample to cover the full width of a burst. - All timings expressed in real time and converted to samples at the capture rate, so behaviour is consistent across SDR sample rates. Profiles (`NoiseBlankerProfile`, default `spike`): spike, ignition, powerline, broadband — each selects the blank window, look-ahead, taper and floor time constant. `threshold` stays orthogonal as the sensitivity knob. Core/protocol: - New `NoiseBlankerProfile` in trx-core (serde/parse/u8/TS), re-exported at the crate root; `RigFilterState.sdr_nb_profile` for state sync. - `profile` added to `RigCommand`/`ClientCommand::SetSdrNoiseBlanker`, the trait method, and the command mapping. Config: `[rig.sdr.noise_blanker] profile = "spike"` (regenerated trx-rs.toml.example). SDR backend: `NoiseBlanker` rewritten in the channel DSP; profile wired through `SoapySdrConfig`, the runtime setter, and `filter_state()`. Frontend: an "NB profile" selector in the SDR advanced controls (POST /set_sdr_noise_blanker&profile=…), reflecting server state; the profile rides along with the enable/threshold quick toggle so it is preserved. Regenerated generated.ts and app.js. Tests: profile u8/parse round-trips (trx-core); DSP tests for impulse suppression with no leading-edge leak, strong-steady-signal pass-through, and wider-profile-blanks-longer. Docs: User-Manual NB section rewritten for the new algorithm and profiles. Signed-off-by: Stan Grams <sjg@haxx.space>