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Refactor sample processing

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This commit is contained in:
Jan Hamal Dvořák 2024-07-23 21:51:48 +02:00
parent 178ba7bee0
commit f294b09c98
1 changed files with 39 additions and 29 deletions
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68
src/main.c
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@ -395,33 +395,44 @@ static void rf_rx_stop(void)
dma_t_samp = -1;
}
inline static int next_sample(const uint32_t *buf, int *h)
struct IQ {
int I, Q;
};
inline static struct IQ next_sample(const uint32_t *buf)
{
int x3 = 2 * (buf[0] - buf[1]);
int x2 = 0;
int x1 = 2 * (buf[5] - buf[4]);
int x0 = 0;
static int h[11];
int x3 = buf[0] - buf[1];
int x2 = buf[2] - buf[3];
int x1 = buf[5] - buf[4];
int x0 = buf[7] - buf[6];
const int c[] = { 4, 2, -8, -9, 19, 55 };
int sample = 0;
sample += (c[0]) * h[10];
sample += (c[0] + c[1]) * h[9];
sample += (c[0] + c[1] + c[2]) * h[8];
sample += (c[0] + c[1] + c[2] + c[3]) * h[7];
sample += (c[1] + c[2] + c[3] + c[4]) * h[6];
sample += (c[2] + c[3] + c[4] + c[5]) * h[5];
sample += (c[3] + c[4] + c[5] + c[5]) * h[4];
sample += (c[4] + c[5] + c[5] + c[4]) * h[3];
sample += (c[5] + c[5] + c[4] + c[3]) * h[2];
sample += (c[5] + c[4] + c[3] + c[2]) * h[1];
sample += (c[4] + c[3] + c[2] + c[1]) * h[0];
sample += (c[3] + c[2] + c[1] + c[0]) * x3;
sample += (c[2] + c[1] + c[0]) * x2;
sample += (c[1] + c[0]) * x1;
sample += (c[0]) * x0;
sample *= gain;
sample /= 256;
int I = 0, Q = 0;
Q += (c[0]) * h[10];
I += (c[0] + c[1]) * h[9];
Q += (c[0] + c[1] + c[2]) * h[8];
I += (c[0] + c[1] + c[2] + c[3]) * h[7];
Q += (c[1] + c[2] + c[3] + c[4]) * h[6];
I += (c[2] + c[3] + c[4] + c[5]) * h[5];
Q += (c[3] + c[4] + c[5] + c[5]) * h[4];
I += (c[4] + c[5] + c[5] + c[4]) * h[3];
Q += (c[5] + c[5] + c[4] + c[3]) * h[2];
I += (c[5] + c[4] + c[3] + c[2]) * h[1];
Q += (c[4] + c[3] + c[2] + c[1]) * h[0];
I += (c[3] + c[2] + c[1] + c[0]) * x3;
Q += (c[2] + c[1] + c[0]) * x2;
I += (c[1] + c[0]) * x1;
Q += (c[0]) * x0;
I *= gain;
I /= 128;
Q *= gain;
Q /= 128;
h[10] = h[6];
h[9] = h[5];
@ -435,14 +446,12 @@ inline static int next_sample(const uint32_t *buf, int *h)
h[1] = x1;
h[0] = x0;
return sample;
return (struct IQ){ I, Q };
}
static void rf_rx(void)
{
const uint32_t base = (uint32_t)rx_cos;
int prevI[11] = { 0 };
int prevQ[11] = { 0 };
int pos = 0;
while (true) {
@ -480,9 +489,10 @@ static void rf_rx(void)
int64_t max_amplitude = CLK_SYS_HZ / 2 / sample_rate;
for (int i = 0; i < IQ_SAMPLES; i++) {
int64_t I = next_sample(cos_ptr + 0, prevI);
int64_t Q = next_sample(cos_ptr + 2, prevQ);
cos_ptr += 8;
struct IQ IQ = next_sample(cos_ptr);
int64_t I = IQ.I;
int64_t Q = IQ.Q;
cos_ptr += 2 * DECIMATE;
I -= (max_amplitude * 181) / 256;
I /= max_amplitude;