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Improve and stabilize sampling delta

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Signed-off-by: Jan Hamal Dvořák <mordae@anilinux.org>
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Jan Hamal Dvořák 2024-01-27 12:39:33 +01:00
parent 38b4bc8b7b
commit 8ca3a3d2bf
1 changed files with 13 additions and 12 deletions
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src/main.c
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@ -426,7 +426,8 @@ static void rf_rx(void)
int frequency = 0; int frequency = 0;
int stride = 0; int stride = 0;
int delta_watermark = 0; int delta_avg = 1;
int prev_delta_netto = 0;
unsigned prev_transfers = 0; unsigned prev_transfers = 0;
int prev_angle = 0; int prev_angle = 0;
@ -452,23 +453,23 @@ static void rf_rx(void)
dma_channel_start(rx_dma); dma_channel_start(rx_dma);
int delta = ~dma_hw->ch[rx_dma].transfer_count - prev_transfers; int delta = ~dma_hw->ch[rx_dma].transfer_count - prev_transfers;
delta_avg = (delta_avg * 1023 + delta * 1024) / 1024;
int delta_netto = delta_avg / 1024;
int acceptable_deviation = delta_watermark / 32 + 1; if (delta_netto == (prev_delta_netto - 1)) {
delta_netto = prev_delta_netto;
if (delta < (delta_watermark - acceptable_deviation)) { } else {
delta_watermark--; prev_delta_netto = delta_netto;
} else if (delta > (delta_watermark + acceptable_deviation)) {
delta_watermark++;
} }
while (delta < delta_watermark) { while (delta < delta_netto) {
if (!dma_channel_is_busy(rx_dma)) if (!dma_channel_is_busy(rx_dma))
dma_channel_start(rx_dma); dma_channel_start(rx_dma);
delta = ~dma_hw->ch[rx_dma].transfer_count - prev_transfers; delta = ~dma_hw->ch[rx_dma].transfer_count - prev_transfers;
} }
prev_transfers += delta_watermark; prev_transfers += delta_netto;
unsigned pos = (prev_transfers - NUM_SAMPLES - 2) & (LO_WORDS - 1); unsigned pos = (prev_transfers - NUM_SAMPLES - 2) & (LO_WORDS - 1);
#if SPEED == 1 #if SPEED == 1
@ -601,12 +602,12 @@ static void rf_rx(void)
if ((Q < 0) ^ (prevQ < 0)) { if ((Q < 0) ^ (prevQ < 0)) {
stride *= ((I < 0) ^ (Q < 0)) ? 1 : -1; stride *= ((I < 0) ^ (Q < 0)) ? 1 : -1;
period = (63 * period + stride) / 64; period = (63 * period + stride) / 64;
frequency = CLK_SYS_HZ / ((period >> 3) * delta_watermark); frequency = CLK_SYS_HZ / ((period >> 3) * delta_netto);
stride = 0; stride = 0;
} else if ((I < 0) ^ (prevI < 0)) { } else if ((I < 0) ^ (prevI < 0)) {
stride *= ((I < 0) ^ (Q < 0)) ? -1 : 1; stride *= ((I < 0) ^ (Q < 0)) ? -1 : 1;
period = (63 * period + stride) / 64; period = (63 * period + stride) / 64;
frequency = CLK_SYS_HZ / ((period >> 3) * delta_watermark); frequency = CLK_SYS_HZ / ((period >> 3) * delta_netto);
stride = 0; stride = 0;
} else { } else {
stride += 1024; stride += 1024;
@ -636,7 +637,7 @@ static void rf_rx(void)
status.rssi_raw = assi2 / 16; status.rssi_raw = assi2 / 16;
status.frequency = frequency; status.frequency = frequency;
status.sample_rate = CLK_SYS_HZ / (delta_watermark * 32); status.sample_rate = CLK_SYS_HZ / (delta_netto * 32);
status.angle = rotation << 16; status.angle = rotation << 16;
status.I = I; status.I = I;
status.Q = Q; status.Q = Q;