mordae/pico-sdr
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Randomize bias delay to reduce artifacts

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This commit is contained in:
Jan Hamal Dvořák 2024-07-10 20:32:24 +02:00
parent 57e36203aa
commit c188d809df
1 changed files with 16 additions and 39 deletions
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55
src/main.c
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@ -91,40 +91,6 @@ inline static uint32_t rnd_next()
return rnd;
}
static void bias_set_delay(int delay)
{
delay += 200;
if (delay < 0)
delay = 0;
if (delay >= 200)
delay = 512;
int bulk = delay / 16;
int rest = delay % 16;
if (0 == rest) {
bulk -= 1;
rest = 16;
}
if (delay > 0) {
if (bulk) {
pio1->instr_mem[11] = pio_encode_set(pio_x, bulk) |
pio_encode_sideset(1, 0) | pio_encode_delay(rest - 1);
} else {
pio1->instr_mem[11] = pio_encode_jmp(10) | pio_encode_sideset(1, 0) |
pio_encode_delay(rest - 1);
}
pio_sm_set_wrap(pio1, 0, 10, 12);
} else {
pio_sm_set_wrap(pio1, 0, 10, 10);
pio_sm_exec(pio1, 0, pio_encode_jmp(10));
}
}
static void bias_init(int in_pin, int out_pin)
{
gpio_disable_pulls(in_pin);
@ -138,8 +104,20 @@ static void bias_init(int in_pin, int out_pin)
const uint16_t insn[] = {
pio_encode_mov_not(pio_pins, pio_pins) | pio_encode_sideset(1, 1),
pio_encode_set(pio_x, 31) | pio_encode_sideset(1, 0) | pio_encode_delay(15),
pio_encode_jmp_x_dec(2) | pio_encode_sideset(1, 0) | pio_encode_delay(15),
pio_encode_in(pio_pins, 1),
pio_encode_in(pio_pins, 1),
pio_encode_in(pio_pins, 1),
pio_encode_in(pio_pins, 1),
pio_encode_in(pio_pins, 1),
pio_encode_in(pio_pins, 1),
pio_encode_in(pio_pins, 1),
pio_encode_in(pio_pins, 1),
pio_encode_mov(pio_x, pio_isr),
pio_encode_mov(pio_isr, pio_null),
pio_encode_jmp_x_dec(11),
};
pio_program_t prog = {
@ -156,6 +134,7 @@ static void bias_init(int in_pin, int out_pin)
pio_add_program(pio1, &prog);
pio_sm_config pc = pio_get_default_sm_config();
sm_config_set_in_shift(&pc, false, false, 32);
sm_config_set_sideset(&pc, 1, false, true);
sm_config_set_sideset_pins(&pc, out_pin);
sm_config_set_in_pins(&pc, in_pin);
@ -600,6 +579,7 @@ static void rf_rx(void)
iq_queue_pos = (iq_queue_pos + 1) & (IQ_QUEUE_LEN - 1);
}
/* Randomize LO phase in the next word. */
for (int i = 0; i < 8; i++) {
lo_tweak(lo_cos, COS_PHASE);
lo_tweak(lo_sin, SIN_PHASE);
@ -620,9 +600,6 @@ static void run_command(uint8_t cmd, uint32_t arg)
} else if (0x04 == cmd) {
/* Set the tuner gain level */
gain = INIT_GAIN * powf(10.0f, 0.005f * arg);
} else if (0x05 == cmd) {
/* Set PPM error - hack to tweak bias strength */
bias_set_delay(arg);
} else if (0x0d == cmd) {
/* Set tuner gain by the tuner's gain index */
if (arg < NUM_GAINS) {