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freq_est: make ramp-up delta phase check more strict

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This should help with occasional jumps in the estimated carrier frequency on
receivers running frequency tracking.
This commit is contained in:
Thomas Kolb 2024-09-12 23:49:57 +02:00
parent eb802629a1
commit 706a1eb437
1 changed files with 2 additions and 2 deletions
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4
impl/src/layer1/freq_est.c
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@ -143,7 +143,7 @@ float freq_est_in_rampup(const float complex *recv, size_t n, float *final_phase
// rotate every second symbol by 180°. As a plausibility check that we are
// in fact inside the ramp-up, we verify that there is no phase rotation by
// more than 90° between the symbols.
// more than 60° between the symbols.
for(size_t i = 0; i < n; i++) {
if((i % 2) == 0) {
rotated[i] = recv[i];
@ -154,7 +154,7 @@ float freq_est_in_rampup(const float complex *recv, size_t n, float *final_phase
float phase = cargf(rotated[i]);
if(i > 0) {
float phase_delta = phase - prev_phase;
if(fabsf(phase_delta) > 3.14159f/2.0f) {
if(fabsf(phase_delta) > 3.14159f/3.0f) {
// abort because we either have the wrong signal or too much noise.
if(final_phase) {
*final_phase = 0.0f;