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rds FIR filter.

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silence, rds_text options.
This commit is contained in:
Jean-François DEL NERO 2022-11-27 11:27:22 +01:00
parent c61d30a7f0
commit 2050b0443f
3 changed files with 72 additions and 19 deletions
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85
src/broadcast_fm/broadcast_fm.c
View File

@ -84,7 +84,7 @@
// ________ Stereo L - R modulation
// / \ 38KHz DSB-SC
// / \ _______ _______
// / MONO \ Pilot / \ / \ RDS
// / MONO \ Pilot / \ / \ RDS (57KHz DSB-SC)
// / L + R \ | / \ / \ _ _
// / \__|__/ \/ \__/ \/ \___
//30Hz 15Khz | | | | |
@ -144,11 +144,16 @@
#include "fir_filters/FIR_Audio_Filter_Filter.h"
#include "fir_filters/AudioPreemphasis_Filter.h"
#include "fir_filters/FIR_RDS_Passband_Filter.h"
#ifdef CONFIG_BASEBAND_FILTER
#include "fir_filters/FM_Baseband_Filter.h"
#endif
#include "hxcmod/hxcmod.h"
#define IQ_SAMPLE_RATE 2000000
#define SUBCARRIERS_SAMPLE_RATE 200000
#define IQ_SAMPLE_RATE 2000000
#define SUBCARRIERS_SAMPLE_RATE 200000
#define IF_FREQ 0
@ -227,6 +232,7 @@ void printhelp(char* argv[])
printf(" -stdout \t\t\t: IQ stream send to stdout\n");
printf(" -mono \t\t\t: Mono FM mode\n");
printf(" -no_rds \t\t\t: Disable RDS\n");
printf(" -silence \t\t\t: No sound\n");
printf(" -mod_file:[MODFILE.MOD]\t: MOD music file to play\n");
printf(" -generate \t\t\t: Generate the IQ stream\n");
printf(" -help \t\t\t: This help\n\n");
@ -240,6 +246,7 @@ int main(int argc, char* argv[])
FILE *f;
char filename[512];
char rdstxt[512];
int mod_data_size = 0;
unsigned char * mod_data;
@ -262,8 +269,10 @@ int main(int argc, char* argv[])
FIR_Audio_Filter_Filter leftplusright_audio_filter,leftminusright_audio_filter;
AudioPreemphasis_Filter preamphasis_left_filter,preamphasis_right_filter;
//FM_Baseband_Filter fmband_filter;
FIR_RDS_Passband_Filter rds_filter;
#ifdef CONFIG_BASEBAND_FILTER
FM_Baseband_Filter fmband_filter;
#endif
iq_wave_gen iqgen;
wave_gen audio_l_gen;
@ -282,11 +291,12 @@ int main(int argc, char* argv[])
int16_t subcarriers_dbg_wave_buf[BUFFER_SAMPLES_SIZE];
double subcarriers_float_wave_buf[BUFFER_SAMPLES_SIZE];
int monomode, no_rds;
int monomode, no_rds, silence;
stdoutmode = 0;
monomode = 0;
no_rds = 0;
silence = 0;
if(isOption(argc,argv,"stdout",NULL)>0)
{
@ -324,7 +334,12 @@ int main(int argc, char* argv[])
{
no_rds = 1;
}
if(isOption(argc,argv,"silence",NULL)>0)
{
silence = 1;
}
if(isOption(argc,argv,"generate",0)>0)
{
// Init the .mod player and load the mod file.
@ -362,8 +377,11 @@ int main(int argc, char* argv[])
AudioPreemphasis_Filter_init(&preamphasis_right_filter);
FIR_Audio_Filter_Filter_init(&leftplusright_audio_filter);
FIR_Audio_Filter_Filter_init(&leftminusright_audio_filter);
FIR_RDS_Passband_Filter_init(&rds_filter);
//FM_Baseband_Filter_init(&fmband_filter);
#ifdef CONFIG_BASEBAND_FILTER
FM_Baseband_Filter_init(&fmband_filter);
#endif
// Init oscillators
@ -403,6 +421,10 @@ int main(int argc, char* argv[])
rds_carrier_57KHz_gen.sample_rate = SUBCARRIERS_SAMPLE_RATE;
init_rds_encoder(&rdsstat,SUBCARRIERS_SAMPLE_RATE);
if(isOption(argc,argv,"rdstxt",(char*)&rdstxt)>0)
{
set_rds_text(&rdsstat,rdstxt);
}
// IQ Modulator
iqgen.phase = 0;
@ -451,23 +473,39 @@ int main(int argc, char* argv[])
if(audio_r_gen.Amplitude < 0) audio_r_gen.Amplitude = 0;
if(audio_l_gen.Amplitude < 0) audio_l_gen.Amplitude = 0;
// Get the left and right samples.
audio_sample_l = f_get_next_sample(&audio_l_gen);
audio_sample_r = f_get_next_sample(&audio_r_gen);
if(!silence)
{
// Get the left and right samples.
audio_sample_l = f_get_next_sample(&audio_l_gen);
audio_sample_r = f_get_next_sample(&audio_r_gen);
}
else
{
audio_sample_l = 0;
audio_sample_r = 0;
}
}
else
{
if(!(j&3))
if(!silence)
{
audio_sample_l = ((double)((mod_wave_buf[((j/4)*2)]) / (double)32768)) * (double)22.5;
audio_sample_r = ((double)((mod_wave_buf[((j/4)*2)+1]) / (double)32768)) * (double)22.5;
if(!(j&3))
{
audio_sample_l = ((double)((mod_wave_buf[((j/4)*2)]) / (double)32768)) * (double)22.5;
audio_sample_r = ((double)((mod_wave_buf[((j/4)*2)+1]) / (double)32768)) * (double)22.5;
// Left & Right Preamphasis filter.
AudioPreemphasis_Filter_put(&preamphasis_left_filter, audio_sample_l );
audio_sample_l = AudioPreemphasis_Filter_get(&preamphasis_left_filter);
// Left & Right Preamphasis filter.
AudioPreemphasis_Filter_put(&preamphasis_left_filter, audio_sample_l );
audio_sample_l = AudioPreemphasis_Filter_get(&preamphasis_left_filter);
AudioPreemphasis_Filter_put(&preamphasis_right_filter, audio_sample_r );
audio_sample_r = AudioPreemphasis_Filter_get(&preamphasis_right_filter);
AudioPreemphasis_Filter_put(&preamphasis_right_filter, audio_sample_r );
audio_sample_r = AudioPreemphasis_Filter_get(&preamphasis_right_filter);
}
}
else
{
audio_sample_l = 0;
audio_sample_r = 0;
}
}
@ -504,6 +542,9 @@ int main(int argc, char* argv[])
// 57KHz DSB-SC (Double-sideband suppressed-carrier) modulation
rds_sample = f_get_next_sample(&rds_carrier_57KHz_gen); // Get the 57KHz carrier
rds_sample = ( rds_sample * rds_mod_sample ); // And multiply it with the rds sample.
FIR_RDS_Passband_Filter_put(&rds_filter, rds_sample );
rds_sample = FIR_RDS_Passband_Filter_get(&rds_filter);
}
else
{
@ -547,7 +588,13 @@ int main(int argc, char* argv[])
{
old_freq += interpolation_step;
#ifdef CONFIG_BASEBAND_FILTER
FM_Baseband_Filter_put(&fmband_filter, old_freq );
iqgen.Frequency = ((double)IF_FREQ + FM_Baseband_Filter_get(&fmband_filter));
#else
iqgen.Frequency = ((double)IF_FREQ + old_freq);
#endif
iq_wave_buf[(j*(IQ_SAMPLE_RATE/SUBCARRIERS_SAMPLE_RATE))+k] = get_next_iq(&iqgen);
}

5
src/broadcast_fm/rds.c
View File

@ -59,6 +59,11 @@ void init_rds_encoder(rds_stat * stat,int sample_rate)
strcpy(stat->station_name,"- RDS - - RDS - - RDS - - RDS - --TEST----TEST----TEST----TEST----TEST----TEST--\n");
}
void set_rds_text(rds_stat * stat,char * text)
{
strncpy(stat->station_name,text,256);
}
int rds_differential_encoder(rds_stat * stat)
{
stat->current_diff_dat_state = ((stat->ser_data_in & 1) ^ stat->current_diff_dat_state);

1
src/broadcast_fm/rds.h
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@ -53,3 +53,4 @@ typedef struct _rds_stat
void init_rds_encoder(rds_stat * stat,int sample_rate);
double get_rds_bit_state(rds_stat * stat, double pilot_phase);
void set_rds_text(rds_stat * stat,char * text);