radio95/fm95
0
1
Fork 0
mirror of https://github.com/radio95-rnt/fm95.git synced 2026-07-29 15:59:14 +02:00
Code Issues Activity

dont work for me

Browse Source
This commit is contained in:
kuba
2026-07-11 22:14:09 +02:00
parent d9691aec4d
commit dc7b5d78cf
3 changed files with 0 additions and 137 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/qpsk.c
-66
View File
@@ -1,66 +0,0 @@
#include "qpsk.h"
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define OQPSK_RRC_DELAY 6 // filter delay in symbols (liquid's "m" param)
static void oqpsk_next_dibit(OQPSKMod *m, float *i, float *q) {
uint8_t b0 = m->last_bits[0], b1 = m->last_bits[1], bit;
if (bit_ring_read1(m->bitring, &bit)) b0 = bit;
if (bit_ring_read1(m->bitring, &bit)) b1 = bit;
m->last_bits[0] = b0;
m->last_bits[1] = b1;
*i = b0 ? -1.0f : 1.0f;
*q = b1 ? -1.0f : 1.0f;
}
void oqpsk_init(OQPSKMod *m, float if_freq, float sample_rate, float symbol_rate, float alpha, bit_ring_t *bitring) {
memset(m, 0, sizeof(*m));
init_oscillator(&m->carrier, if_freq, sample_rate);
m->sps = (int)roundf(sample_rate / symbol_rate);
if (m->sps < 2) m->sps = 2;
if (m->sps % 2 != 0) m->sps += 1; // must be even for the half-symbol Q delay
m->fir_i = firfilt_rrrf_create_rnyquist(LIQUID_FIRFILT_RRC, m->sps, OQPSK_RRC_DELAY, alpha, 0.0f);
m->fir_q = firfilt_rrrf_create_rnyquist(LIQUID_FIRFILT_RRC, m->sps, OQPSK_RRC_DELAY, alpha, 0.0f);
m->q_delay_len = m->sps / 2;
m->q_delay = calloc(m->q_delay_len, sizeof(float));
m->q_delay_pos = 0;
m->symbol_clock = 0;
m->sym_i = m->sym_q = 1.0f;
m->bitring = bitring;
}
float oqpsk_process(OQPSKMod *m) {
float impulse_i = 0.0f, impulse_q = 0.0f;
if (m->symbol_clock == 0) {
oqpsk_next_dibit(m, &m->sym_i, &m->sym_q);
impulse_i = m->sym_i * (float)m->sps;
impulse_q = m->sym_q * (float)m->sps;
}
m->symbol_clock = (m->symbol_clock + 1) % m->sps;
float filt_i, filt_q_raw;
firfilt_rrrf_push(m->fir_i, impulse_i);
firfilt_rrrf_execute(m->fir_i, &filt_i);
firfilt_rrrf_push(m->fir_q, impulse_q);
firfilt_rrrf_execute(m->fir_q, &filt_q_raw);
float filt_q = m->q_delay[m->q_delay_pos];
m->q_delay[m->q_delay_pos] = filt_q_raw;
m->q_delay_pos = (m->q_delay_pos + 1) % m->q_delay_len;
float c = get_oscillator_cos_sample(&m->carrier);
float s = get_oscillator_sin_sample(&m->carrier);
return filt_i * c - filt_q * s;
}
void oqpsk_destroy(OQPSKMod *m) {
firfilt_rrrf_destroy(m->fir_i);
firfilt_rrrf_destroy(m->fir_q);
free(m->q_delay);
}
lib/qpsk.h
-22
View File
@@ -1,22 +0,0 @@
#pragma once
#include <liquid/liquid.h>
#include "oscillator.h"
#include "bit_ring.h"
typedef struct {
Oscillator carrier; // IF carrier (e.g. 3 kHz)
firfilt_rrrf fir_i, fir_q; // liquid RRC matched-filter shapers
float *q_delay;
int q_delay_len;
int q_delay_pos;
int sps; // samples per symbol
int symbol_clock;
float sym_i, sym_q;
bit_ring_t *bitring;
uint8_t last_bits[2]; // hold last symbol if bitring runs dry
} OQPSKMod;
void oqpsk_init(OQPSKMod *m, float if_freq, float sample_rate, float symbol_rate, float alpha, bit_ring_t *bitring);
float oqpsk_process(OQPSKMod *m);
void oqpsk_destroy(OQPSKMod *m);