mordae/pico-sdr
1
2
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Implement fixed off-tuning

Browse source
This commit is contained in:
Jan Hamal Dvořák 2024-07-02 01:56:08 +02:00
parent 7f98ab98f0
commit 6e70ef1433
1 changed files with 31 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

49
src/main.c
View file

@ -38,9 +38,9 @@
static uint32_t lo_cos[LO_WORDS] __attribute__((__aligned__(1 << LO_BITS_DEPTH)));
static uint32_t lo_sin[LO_WORDS] __attribute__((__aligned__(1 << LO_BITS_DEPTH)));
#define DECIMATE 2
#define DECIMATE 4
#define RX_STRIDE (2 * IQ_SAMPLES * DECIMATE)
#define RX_BITS_DEPTH 12
#define RX_BITS_DEPTH 13
#define RX_WORDS (1 << (RX_BITS_DEPTH - 2))
static_assert(RX_STRIDE * 4 < RX_WORDS, "RX_STRIDE * 4 < RX_WORDS");
@ -463,7 +463,6 @@ static void rf_rx(void)
int pos = 0;
int64_t dcI = 0, dcQ = 0;
int prevI = 0, prevQ = 0;
while (true) {
if (multicore_fifo_rvalid()) {
@ -520,8 +519,32 @@ static void rf_rx(void)
cos_pos = *cos_ptr++;
int I2 = cos_neg - cos_pos;
int64_t I = (prevI + I1 + I1 + I2) / 2;
prevI = I2;
cos_neg = *cos_ptr++;
cos_pos = *cos_ptr++;
int I3 = cos_neg - cos_pos;
cos_neg = *cos_ptr++;
cos_pos = *cos_ptr++;
int I4 = cos_neg - cos_pos;
uint32_t sin_neg = *sin_ptr++;
uint32_t sin_pos = *sin_ptr++;
int Q1 = sin_neg - sin_pos;
sin_neg = *sin_ptr++;
sin_pos = *sin_ptr++;
int Q2 = sin_neg - sin_pos;
sin_neg = *sin_ptr++;
sin_pos = *sin_ptr++;
int Q3 = sin_neg - sin_pos;
sin_neg = *sin_ptr++;
sin_pos = *sin_ptr++;
int Q4 = sin_neg - sin_pos;
int64_t I = I1 - I3 + Q2 - Q4;
int64_t Q = Q1 - Q3 - I2 + I4;
int64_t I16 = I << 16;
dcI = ((dcI << 16) - dcI + I16) >> 16;
@ -537,17 +560,6 @@ static void rf_rx(void)
*blockptr++ = I + 128;
uint32_t sin_neg = *sin_ptr++;
uint32_t sin_pos = *sin_ptr++;
int Q1 = sin_neg - sin_pos;
sin_neg = *sin_ptr++;
sin_pos = *sin_ptr++;
int Q2 = sin_neg - sin_pos;
int64_t Q = (prevQ + Q1 + Q1 + Q2) / 2;
prevQ = Q2;
int64_t Q16 = Q << 16;
dcQ = ((dcQ << 16) - dcQ + Q16) >> 16;
Q = (Q16 - dcQ) >> 16;
@ -573,11 +585,12 @@ static void run_command(uint8_t cmd, uint32_t arg)
{
if (0x01 == cmd) {
/* Tune to a new center frequency */
rx_lo_init(arg, true);
rx_lo_init(arg - sample_rate, true);
} else if (0x02 == cmd) {
/* Set the rate at which IQ sample pairs are sent */
sample_rate = arg;
dma_timer_set_fraction(dma_t_samp, 1, CLK_SYS_HZ / (sample_rate * DECIMATE));
rx_lo_init(arg - sample_rate, true);
} else if (0x04 == cmd) {
/* Set the tuner gain level */
gain = INIT_GAIN * powf(10.0f, 0.005f * arg);
@ -701,7 +714,7 @@ int main()
queue_init(&iq_queue, sizeof(uint8_t *), IQ_QUEUE_LEN);
rx_lo_init(INIT_FREQ, true);
rx_lo_init(INIT_FREQ - INIT_SAMPLE_RATE, true);
while (true) {
if (check_command() > 0) {