From 32822effdaa1679d02c2b56a5567b9ced6007d04 Mon Sep 17 00:00:00 2001 From: Stan Grams Date: Sat, 28 Feb 2026 23:55:17 +0100 Subject: [PATCH] [fix](trx-backend-soapysdr): retune wfm sum and diff cutoffs Co-authored-by: OpenAI Codex Signed-off-by: Stan Grams --- .../trx-backend/trx-backend-soapysdr/src/demod.rs | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/src/trx-server/trx-backend/trx-backend-soapysdr/src/demod.rs b/src/trx-server/trx-backend/trx-backend-soapysdr/src/demod.rs index c2c97b0..74ad56f 100644 --- a/src/trx-server/trx-backend/trx-backend-soapysdr/src/demod.rs +++ b/src/trx-server/trx-backend/trx-backend-soapysdr/src/demod.rs @@ -11,14 +11,13 @@ const RDS_BPF_Q: f32 = 10.0; /// Pilot tone frequency (Hz). const PILOT_HZ: f32 = 19_000.0; /// Audio bandwidth for WFM (Hz). -/// 15.8 kHz leaves more guard band below the 19 kHz pilot and reduces -/// top-end artifacts on strong signals while still preserving the useful -/// broadcast audio range. -const AUDIO_BW_HZ: f32 = 15_800.0; +/// 17 kHz preserves more top-end while still leaving guard band below the +/// 19 kHz pilot. +const AUDIO_BW_HZ: f32 = 17_000.0; /// Stereo L-R subchannel bandwidth for WFM (Hz). /// Keep this a bit lower than the mono path because the recovered difference /// signal is noisier and more prone to high-frequency artifacts. -const STEREO_DIFF_BW_HZ: f32 = 14_500.0; +const STEREO_DIFF_BW_HZ: f32 = 15_800.0; /// Q values for a proper 4th-order Butterworth cascade (two 2nd-order stages). /// Stage 1: Q = 1 / (2 cos(π/8)) const BW4_Q1: f32 = 0.5412;