mordae/pico-sdr
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Replace constant gain with AGC

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This commit is contained in:
Jan Hamal Dvořák 2024-02-24 23:40:28 +01:00
parent daea0dd8bf
commit a2b38be6cf
1 changed files with 10 additions and 16 deletions
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26
src/main.c
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@ -550,12 +550,7 @@ static void rf_rx(void)
int lpQa3 = 0;
int64_t dcI = 0, dcQ = 0;
/*
* CLK / BW for oversampling, but 1/2 for the -1/0/0/1 PIO outcomes.
* Signal can get outside due to DC offset compensation.
*/
const int amp_max = CLK_SYS_HZ / 2 / BANDWIDTH * DECIMATION;
int64_t agc = 127;
while (true) {
if (multicore_fifo_rvalid()) {
@ -639,20 +634,19 @@ static void rf_rx(void)
dI = ((dI << 19) - dcI) >> 19;
dQ = ((dQ << 19) - dcQ) >> 19;
if (dI > amp_max)
dI = amp_max;
dI <<= 32;
dQ <<= 32;
if (dI < -amp_max)
dI = -amp_max;
agc -= (1 << 12) / DECIMATION * BANDWIDTH;
if (dQ > amp_max)
dQ = amp_max;
if (llabs(dI) > agc)
agc = llabs(dI);
if (dQ < -amp_max)
dQ = -amp_max;
if (llabs(dQ) > agc)
agc = llabs(dQ);
*blockptr++ = 127 * dI / amp_max;
*blockptr++ = 127 * dQ / amp_max;
*blockptr++ = 127 * dI / agc;
*blockptr++ = 127 * dQ / agc;
}
if (!queue_try_add(&iq_queue, block)) {