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[perf](trx-backend-soapysdr): streamline wfm decode loop

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Signed-off-by: Stan Grams <sjg@haxx.space>
This commit is contained in:
Stan Grams
2026-03-01 01:19:47 +01:00
parent b42e557a25
commit 926a02e043
1 changed files with 14 additions and 6 deletions
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src/trx-server/trx-backend/trx-backend-soapysdr/src/demod.rs
+14 -6
View File
@@ -636,17 +636,26 @@ impl WfmStereoDecoder {
}
pub fn process_iq(&mut self, samples: &[Complex<f32>]) -> Vec<f32> {
let composite = demod_fm_with_prev(samples, &mut self.prev_iq);
if composite.is_empty() {
if samples.is_empty() {
return Vec::new();
}
let inv_pi = std::f32::consts::FRAC_1_PI;
let mut output = Vec::with_capacity(
((composite.len() as f64 * self.output_phase_inc).ceil() as usize + 1)
((samples.len() as f64 * self.output_phase_inc).ceil() as usize + 1)
* self.output_channels.max(1),
);
let (trim_sin, trim_cos) = STEREO_SEPARATION_PHASE_TRIM.sin_cos();
for &sample in samples {
let x = if let Some(prev_sample) = self.prev_iq {
let product = sample * prev_sample.conj();
fast_atan2(product.im, product.re) * inv_pi
} else {
0.0
};
self.prev_iq = Some(sample);
for x in composite {
// Normalize discriminator output so ±75 kHz deviation maps to ±1.0.
let x = x * self.fm_gain;
@@ -656,7 +665,7 @@ impl WfmStereoDecoder {
let (sin_p, cos_p) = self.pilot_phase.sin_cos();
let i = self.pilot_i_lp.process(pilot_tone * cos_p);
let q = self.pilot_q_lp.process(pilot_tone * -sin_p);
let phase_err = q.atan2(i);
let phase_err = fast_atan2(q, i);
let pilot_phase_est = self.pilot_phase + phase_err;
self.pilot_phase += self.pilot_freq;
self.pilot_phase = self.pilot_phase.rem_euclid(std::f32::consts::TAU);
@@ -734,7 +743,6 @@ impl WfmStereoDecoder {
let blend_i =
(self.prev_blend + frac * (stereo_blend_target - self.prev_blend)).clamp(0.0, 1.0);
self.prev_blend = stereo_blend_target;
let (trim_sin, trim_cos) = STEREO_SEPARATION_PHASE_TRIM.sin_cos();
let diff_i = (diff_i * trim_cos + diff_q * trim_sin) * STEREO_SEPARATION_GAIN;
// --- Deemphasis + DC block + output ---