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

Improve secondary filter

Browse source
This commit is contained in:
Jan Hamal Dvořák 2024-06-08 11:25:02 +02:00
parent 421d298c86
commit 69d7cd9595
1 changed files with 24 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

31
src/main.c
View file

@ -37,9 +37,9 @@
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");
@ -430,7 +430,8 @@ static void rf_rx(void)
unsigned pos = 0;
int64_t dcI = 0, dcQ = 0;
int prevI = 0, prevQ = 0;
int prevI1 = 0, prevI2 = 0, prevI3 = 0;
int prevQ1 = 0, prevQ2 = 0, prevQ3 = 0;
while (true) {
if (multicore_fifo_rvalid()) {
@ -486,8 +487,16 @@ 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;
int64_t I = (prevI3 + prevI2 * 3 + prevI1 * 4 + I1 * 4 + I2 * 3 + I3) / 4;
prevI1 = I4, prevI2 = I3, prevI3 = I2;
int64_t I16 = I << 16;
dcI = ((dcI << 16) - dcI + I16) >> 16;
@ -511,8 +520,16 @@ static void rf_rx(void)
sin_pos = *sin_ptr++;
int Q2 = sin_neg - sin_pos;
int64_t Q = (prevQ + Q1 + Q1 + Q2) / 2;
prevQ = Q2;
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 Q = (prevQ3 + prevQ2 * 3 + prevQ1 * 4 + Q1 * 4 + Q2 * 3 + Q3) / 4;
prevQ1 = Q4, prevQ2 = Q3, prevQ3 = Q2;
int64_t Q16 = Q << 16;
dcQ = ((dcQ << 16) - dcQ + Q16) >> 16;