mirror of
https://github.com/jfdelnero/rf-tools.git
synced 2024-11-21 11:21:47 -05:00
wip : RDS support.
This commit is contained in:
Jean-François DEL NERO
parent
94f026bfaf
commit
ff13d3d307
@ -128,6 +128,8 @@
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#include "modulator.h"
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#include "rds.h"
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#include "utils.h"
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#include "fir_filters/FIR_Audio_Filter_Filter.h"
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@ -238,6 +240,7 @@ int main(int argc, char* argv[])
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double audio_sample_final;
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double audio_sample_r_car;
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double pilot_sample;
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double rds_sample,rds_mod_sample;
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double balance_sample;
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double fm_mod;
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@ -259,6 +262,9 @@ int main(int argc, char* argv[])
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wave_gen audiow_stereo38KHz_gen;
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wave_gen stereo_pilot_gen;
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wave_gen rds_carrier_57KHz_gen;
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rds_stat rdsstat;
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uint16_t iq_wave_buf[ BUFFER_SAMPLES_SIZE * (IQ_SAMPLE_RATE/SUBCARRIERS_SAMPLE_RATE)];
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int16_t mod_wave_buf[(BUFFER_SAMPLES_SIZE*2)/4];
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@ -347,12 +353,12 @@ int main(int argc, char* argv[])
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// Left and Right audio freq (used if no .mod music file)
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audio_l_gen.phase = 0;
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audio_l_gen.Frequency = 700;
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audio_l_gen.Amplitude = 22.5;
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audio_l_gen.Amplitude = 21.25;
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audio_l_gen.sample_rate = SUBCARRIERS_SAMPLE_RATE;
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audio_r_gen.phase = 0;
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audio_r_gen.Frequency = 1000;
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audio_r_gen.Amplitude = 22.5;
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audio_r_gen.Amplitude = 21.25;
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audio_r_gen.sample_rate = SUBCARRIERS_SAMPLE_RATE;
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// Left <> Right balance LFO (used if no .mod music file)
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@ -373,6 +379,14 @@ int main(int argc, char* argv[])
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audiow_stereo38KHz_gen.Amplitude = 1;
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audiow_stereo38KHz_gen.sample_rate = SUBCARRIERS_SAMPLE_RATE;
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// 57KHz RDS carrier
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rds_carrier_57KHz_gen.phase = 0;
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rds_carrier_57KHz_gen.Frequency = 57000;
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rds_carrier_57KHz_gen.Amplitude = 1;
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rds_carrier_57KHz_gen.sample_rate = SUBCARRIERS_SAMPLE_RATE;
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init_rds_encoder(&rdsstat,SUBCARRIERS_SAMPLE_RATE);
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// IQ Modulator
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iqgen.phase = 0;
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iqgen.Frequency = IF_FREQ;
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@ -456,14 +470,22 @@ int main(int argc, char* argv[])
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FIR_Audio_Filter_Filter_put(&leftminusright_audio_filter, leftminusright_audio);
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leftminusright_audio = FIR_Audio_Filter_Filter_get(&leftminusright_audio_filter);
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// Keep the 18KHz pilot and the 38KHz clock in phase :
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// Keep the 19KHz pilot and the 38KHz clock in phase :
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audiow_stereo38KHz_gen.phase = (stereo_pilot_gen.phase * 2) + PI/2;
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rds_carrier_57KHz_gen.phase = (stereo_pilot_gen.phase * 3) + PI/2;
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rds_mod_sample = get_rds_bit_state(&rdsstat,stereo_pilot_gen.phase);
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// 38KHz DSB-SC (Double-sideband suppressed-carrier) modulation
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audio_sample_r_car = f_get_next_sample(&audiow_stereo38KHz_gen); // Get the 38KHz carrier
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audio_sample_r_car = (audio_sample_r_car * leftminusright_audio ); // And multiply it with the left - right sample.
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// 18KHz pilot
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// 57KHz DSB-SC (Double-sideband suppressed-carrier) modulation
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rds_sample = f_get_next_sample(&rds_carrier_57KHz_gen); // Get the 57KHz carrier
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rds_sample = ( rds_sample * rds_mod_sample ); // And multiply it with the rds sample.
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// 19KHz pilot
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pilot_sample = f_get_next_sample(&stereo_pilot_gen);
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}
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else
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@ -471,11 +493,12 @@ int main(int argc, char* argv[])
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// Mono : No pilot nor 38KHz modulation...
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audio_sample_r_car = 0;
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pilot_sample = 0;
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rds_sample = 0;
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}
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// Mix all signals sources :
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// 45% 45% 10%
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audio_sample_final = ((leftplusright_audio) + audio_sample_r_car + pilot_sample);
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// 42.5% 42.5% 10% 5%
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audio_sample_final = ((leftplusright_audio) + audio_sample_r_car + pilot_sample + rds_sample);
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// Main carrier frequency modulation : +/- 75KHz
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fm_mod = ((audio_sample_final / (double)(100.0)) * (double)(75000));
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@ -485,7 +508,7 @@ int main(int argc, char* argv[])
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//FM_Baseband_Filter_put(&fmband_filter, fm_mod );
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//fm_mod = FM_Baseband_Filter_get(&fmband_filter);
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subcarriers_dbg_wave_buf[j] = fm_mod;
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subcarriers_dbg_wave_buf[j] = fm_mod/4;
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subcarriers_float_wave_buf[j] = fm_mod;
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}
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119
src/broadcast_fm/rds.c
Normal file
119
src/broadcast_fm/rds.c
Normal file
@ -0,0 +1,119 @@
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///////////////////////////////////////////////////////////////////////////////////
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//-------------------------------------------------------------------------------//
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//-------------------------------------------------------------------------------//
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//-----------H----H--X----X-----CCCCC----22222----0000-----0000------11----------//
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//----------H----H----X-X-----C--------------2---0----0---0----0--1--1-----------//
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//---------HHHHHH-----X------C----------22222---0----0---0----0-----1------------//
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//--------H----H----X--X----C----------2-------0----0---0----0-----1-------------//
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//-------H----H---X-----X---CCCCC-----222222----0000-----0000----1111------------//
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//-------------------------------------------------------------------------------//
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//----------------------------------------------------- http://hxc2001.free.fr --//
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///////////////////////////////////////////////////////////////////////////////////
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// File : rds.c
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// Contains: rds engine
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//
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// This file is part of rf-tools.
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//
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// Written by: Jean-François DEL NERO
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//
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// Copyright (C) 2022 Jean-François DEL NERO
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//
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// You are free to do what you want with this code.
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// A credit is always appreciated if you use it into your product :)
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//
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// Change History (most recent first):
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///////////////////////////////////////////////////////////////////////////////////
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#include <stdint.h>
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#include <stdio.h>
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#include <math.h>
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#include <string.h>
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#include "modulator.h"
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#include "rds.h"
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void init_rds_encoder(rds_stat * stat,int sample_rate)
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{
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memset(stat,0,sizeof(rds_stat));
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stat->bit_rate = RDS_BIT_RATE;
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stat->old_pilot_phase = 0;
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stat->sample_rate = sample_rate;
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}
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int rds_differential_encoder(rds_stat * stat)
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{
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stat->current_diff_dat_state = ((stat->ser_data_in & 1) ^ stat->current_diff_dat_state);
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return stat->current_diff_dat_state;
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}
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double get_rds_bit_state(rds_stat * stat, double pilot_phase)
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{
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double sample;
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double phase_diff;
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if(pilot_phase < stat->old_pilot_phase)
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phase_diff = (2*PI + pilot_phase) - stat->old_pilot_phase;
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else
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phase_diff = pilot_phase - stat->old_pilot_phase;
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if( phase_diff >= ((2*PI) / 3) )
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{
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// New 57KHz tick clock
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stat->old_pilot_phase = pilot_phase;//+= ((2*PI) / 3);
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if(stat->old_pilot_phase >= (2*PI))
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stat->old_pilot_phase = 0;
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stat->cycles_count++;
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if(stat->cycles_count >= 16*2)
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{
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stat->test++;
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stat->ser_data_in = rand()&1;
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rds_differential_encoder(stat);
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stat->current_data_state = (stat->current_diff_dat_state & 0x1);
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stat->cycles_count = 0;
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}
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// Delayed signal
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if(stat->cycles_count == 8*2)
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{
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stat->current_data_state = stat->current_diff_dat_state ^ 1;
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}
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}
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#define FREQ_FILTER (1187.5*1.0)
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if(stat->current_data_state)
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{
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// Must go to 0.
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if( !((stat->phase >= ((2*PI) - ((2.0 * PI * (FREQ_FILTER*2))/ (double)stat->sample_rate) ) ) || // >=// 2PI - step
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(stat->phase < (((2.0 * PI * (FREQ_FILTER*2))/ (double)stat->sample_rate) ) ) ) // < // step
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)
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{
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stat->phase += ( (2.0 * PI * (FREQ_FILTER*2) ) / (double)stat->sample_rate );
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if(stat->phase >= 2.0 * PI)
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stat->phase -= (2.0 * PI);
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}
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}
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else
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{
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// Must go to PI.
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if( !((stat->phase >= ((PI) - ((2.0 * PI * (FREQ_FILTER*2))/ (double)stat->sample_rate) ) ) && // > PI - step
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(stat->phase < ((PI) + ((2.0 * PI * (FREQ_FILTER*2))/ (double)stat->sample_rate) ) )) // < PI + step
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)
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{
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stat->phase += ( (2.0 * PI * (FREQ_FILTER*2) ) / (double)stat->sample_rate );
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if(stat->phase >= 2.0 * PI)
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stat->phase -= (2.0 * PI);
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}
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}
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sample = ( cos( stat->phase ) * 3.0 );
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return sample;
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}
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46
src/broadcast_fm/rds.h
Normal file
46
src/broadcast_fm/rds.h
Normal file
@ -0,0 +1,46 @@
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///////////////////////////////////////////////////////////////////////////////////
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//-------------------------------------------------------------------------------//
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//-------------------------------------------------------------------------------//
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//-----------H----H--X----X-----CCCCC----22222----0000-----0000------11----------//
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//----------H----H----X-X-----C--------------2---0----0---0----0--1--1-----------//
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//---------HHHHHH-----X------C----------22222---0----0---0----0-----1------------//
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//--------H----H----X--X----C----------2-------0----0---0----0-----1-------------//
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//-------H----H---X-----X---CCCCC-----222222----0000-----0000----1111------------//
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//-------------------------------------------------------------------------------//
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//----------------------------------------------------- http://hxc2001.free.fr --//
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///////////////////////////////////////////////////////////////////////////////////
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// File : rds.h
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// Contains: rds engine
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//
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// This file is part of rf-tools.
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//
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// Written by: Jean-François DEL NERO
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//
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// Copyright (C) 2022 Jean-François DEL NERO
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//
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// You are free to do what you want with this code.
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// A credit is always appreciated if you use it into your product :)
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//
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// Change History (most recent first):
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///////////////////////////////////////////////////////////////////////////////////
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#define RDS_BIT_RATE 1187.5
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typedef struct _rds_stat
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{
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int sample_rate;
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float bit_rate;
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double old_pilot_phase;
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double phase;
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int current_data_state;
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int current_diff_dat_state;
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int ser_data_in;
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int test;
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int cycles_count;
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}rds_stat;
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void init_rds_encoder(rds_stat * stat,int sample_rate);
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double get_rds_bit_state(rds_stat * stat, double pilot_phase);
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