The RDS encoder and modulator is now working ! :)

build/Makefile

@@ -28,7 +28,7 @@ EXEC=broadcast_fm rf_jammer
 
 all: $(EXEC)
 
-broadcast_fm:  broadcast_fm.o rds.o wave.o modulator.o FIR_Audio_Filter_Filter.o FM_Baseband_Filter.o AudioPreemphasis_Filter.o hxcmod.o rand_gen.o
+broadcast_fm:  broadcast_fm.o rds.o rds_stream_dump.o wave.o modulator.o FIR_Audio_Filter_Filter.o FM_Baseband_Filter.o AudioPreemphasis_Filter.o hxcmod.o rand_gen.o
 	$(CC) -o $@    $^ $(LDFLAGS)
 
 rf_jammer:  rf_jammer.o wave.o modulator.o rand_gen.o
@@ -43,6 +43,9 @@ rf_jammer.o: ../src/rf_jammer/rf_jammer.c
 rds.o: ../src/broadcast_fm/rds.c
 	$(CC) -o $@ -c $< $(CFLAGS)
 
+rds_stream_dump.o: ../src/broadcast_fm/rds_stream_dump.c
+	$(CC) -o $@ -c $< $(CFLAGS)
+
 utils.o: ../src/common/utils.c
 	$(CC) -o $@ -c $< $(CFLAGS)
 

src/broadcast_fm/broadcast_fm.c

@@ -96,7 +96,7 @@
 // ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 // Current software design :
 //
-// Mod player  /  Left Audio  -> Preemphasis (FIR) -> \  / -> Left + Right -> 15KHz low pass (FIR) -------------------------------|
+// Mod player  /  Left Audio  -> Preemphasis (FIR) -> \  / -> Left + Right -> 15KHz low pass (FIR) >------------------------------|
 // Sound                                               \/                                                                         |
 // generator                                           /\                                                                         |
 //             \  Right Audio -> Preemphasis (FIR) -> /  \ -> Left - Right -> 15KHz low pass (FIR)                                |
@@ -108,7 +108,17 @@
 //             |                                                                               38KHz Osc                          |
 //             |                                                                                 (|) (These oscillators           |
 //             |                                                                                 (|)  must be kept in phase)      |
-//                                                                                             19KHz Pilot Osc  ------------------|
+//             |                                                                               19KHz Pilot Osc  >-----------------+
+//             |                                                                                 (|)                              |
+//             |                                                                                 (|)      (57KHz DSB-SC modulated)|
+//             |                                                                               57KHz Osc-->|MUL|>-----------------+
+//                                                                                                |          ^
+//                                                                                           ____ v_____     |
+//                                                                                          |           |    |
+//                                                                                          |    RDS    |>----
+//                                                                                          | Generator |
+//                                                                                          |___________|
+//
 //
 // ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 

src/broadcast_fm/rds.c

@@ -31,6 +31,24 @@
 
 #include "modulator.h"
 #include "rds.h"
+#include "rds_stream_dump.h"
+
+const uint16_t crc_group_xor[]=
+{
+	0xFC,  // A
+	0x198, // B
+	0x168, // C
+	0x1B4, // D
+	0x350  // C'
+};
+
+const uint16_t rds_codes[]=
+{
+	0xF849,
+	0x0CE8,
+	0xF849,
+	0x0000  // Char code.
+};
 
 void init_rds_encoder(rds_stat * stat,int sample_rate)
 {
@@ -38,6 +56,7 @@ void init_rds_encoder(rds_stat * stat,int sample_rate)
 	stat->bit_rate = RDS_BIT_RATE;
 	stat->old_pilot_phase = 0;
 	stat->sample_rate = sample_rate;
+	strcpy(stat->station_name,"- RDS - - RDS - - RDS - - RDS - --TEST----TEST----TEST----TEST----TEST----TEST--\n");
 }
 
 int rds_differential_encoder(rds_stat * stat)
@@ -47,30 +66,147 @@ int rds_differential_encoder(rds_stat * stat)
 	return stat->current_diff_dat_state;
 }
 
+uint32_t rds_crc (uint16_t data)
+{
+	int i;
+	uint16_t crc = 0;
+	int crc_msb;
+
+	for(i=0; i<16; i++)
+	{
+		crc_msb = (crc >> (10-1)) & 1;
+
+		crc <<= 1;
+		if( crc_msb ^ (data >> 15 ) )
+		{
+			crc ^= 0x1B9;
+		}
+
+		data <<= 1;
+	}
+
+	return crc & 0x3FF;
+}
+
+uint32_t encode_rds_bloc(uint16_t data, int group)
+{
+	uint32_t word;
+
+	word = ((uint32_t)data)<<10;
+	word |= (rds_crc (data) ^ crc_group_xor[group]);
+
+	//printf("rds(%d): dat:0x%.4X grp:0x%.4X 0x%.4X\n",group,data,word&0x3FF,word);
+
+	return word;
+}
+
+int get_next_rds_bit(rds_stat * stat)
+{
+	int dat;
+	uint16_t rdsc;
+
+#ifdef USE_RDS_STREAM_BIT
+	if(!rds_stream_dump[stat->current_rds_code_index])
+	{
+		stat->current_rds_code_index = 0;
+		dat = rds_stream_dump[stat->current_rds_code_index];
+	}
+	else
+		dat = rds_stream_dump[stat->current_rds_code_index];
+
+	stat->current_rds_code_index++;
+
+	return dat;
+#endif
+
+	stat->current_bloc_index--;
+
+	if(stat->current_bloc_index<0)
+	{
+		// prepare next bloc
+
+#ifdef USE_RDS_STREAM
+		rdsc = rds_dump[stat->current_rds_code_index];
+		stat->current_bloc = encode_rds_bloc(rdsc, stat->current_rds_code_index&3 );
+		stat->current_rds_code_index++;
+
+		if(stat->current_rds_code_index >= 327*4 )
+		{
+			stat->current_rds_code_index = 0;
+		}
+#else
+		rdsc = rds_codes[stat->current_rds_code_index];
+		if(rdsc)
+		{
+			if( stat->current_rds_code_index == 1)
+			{
+				stat->current_bloc = encode_rds_bloc(rdsc | (stat->station_name_index>>1),stat->current_rds_code_index );
+				stat->current_rds_code_index++;
+			}
+			else
+			{
+				stat->current_bloc = encode_rds_bloc(rdsc,stat->current_rds_code_index);
+				stat->current_rds_code_index++;
+			}
+		}
+		else
+		{
+			rdsc = stat->station_name[stat->station_name_index++];
+			rdsc <<= 8;
+			rdsc |= stat->station_name[stat->station_name_index++];
+
+			stat->current_bloc = encode_rds_bloc(rdsc,stat->current_rds_code_index);
+
+			if(!stat->station_name[stat->station_name_index])
+			{
+				stat->station_name_index = 0;
+			}
+
+			stat->current_rds_code_index = 0;
+		}
+#endif
+
+		stat->current_bloc_index = 25;
+	}
+
+	if( (stat->current_bloc >> (stat->current_bloc_index)) & 0x1 )
+	{
+		dat = 1;
+	}
+	else
+	{
+		dat = 0;
+	}
+
+	//printf("%d",dat);
+
+	return dat;
+}
+
 double get_rds_bit_state(rds_stat * stat, double pilot_phase)
 {
 	double sample;
 	double phase_diff;
 
 	if(pilot_phase < stat->old_pilot_phase)
-		phase_diff = (2*PI + pilot_phase) - stat->old_pilot_phase;
+		phase_diff = ( 2.0 * PI - stat->old_pilot_phase) + pilot_phase;
 	else
 		phase_diff = pilot_phase - stat->old_pilot_phase;
 
-	if( phase_diff >= ((2*PI) / 3) )
+	if( phase_diff >= ( ( 2.0 * PI ) / 3.0 ) ) // 19KHz period / 3 -> 57KHz
 	{
 		// New 57KHz tick clock
-		stat->old_pilot_phase = pilot_phase;//+= ((2*PI) / 3);
+		stat->old_pilot_phase += ( ( 2.0 * PI ) / 3.0 );
 
-		if(stat->old_pilot_phase >= (2*PI))
+		if(stat->old_pilot_phase >= ( 2.0 * PI ))
-			stat->old_pilot_phase = 0;
+			stat->old_pilot_phase -= ( 2.0 * PI );
 
 		stat->cycles_count++;
-		if(stat->cycles_count >= 16*2)
+		if(stat->cycles_count >= 48)
 		{
 			stat->test++;
 
-			stat->ser_data_in = rand()&1;
+			stat->ser_data_in = get_next_rds_bit(stat);
 
 			rds_differential_encoder(stat);
 
@@ -80,13 +216,13 @@ double get_rds_bit_state(rds_stat * stat, double pilot_phase)
 		}
 
 		// Delayed signal
-		if(stat->cycles_count == 8*2)
+		if(stat->cycles_count == 24)
 		{
 			stat->current_data_state = stat->current_diff_dat_state ^ 1;
 		}
 	}
 
-	#define FREQ_FILTER (1187.5*1.0)
+	#define FREQ_FILTER (1187.5*0.50)
 
 	if(stat->current_data_state)
 	{
@@ -113,7 +249,7 @@ double get_rds_bit_state(rds_stat * stat, double pilot_phase)
 		}
 	}
 
-	sample = ( cos( stat->phase ) * 3.0 );
+	sample = ( cos( stat->phase ) * ( 5.0 ) );
 
 	return sample;
 }

src/broadcast_fm/rds.h

@@ -40,6 +40,15 @@ typedef struct _rds_stat
 
 	int test;
 	int cycles_count;
+
+	char station_name[256+1];
+	int  station_name_index;
+
+	uint32_t current_bloc;
+	int current_bloc_index;
+
+	int current_rds_code_index;
+
 }rds_stat;
 
 void init_rds_encoder(rds_stat * stat,int sample_rate);

src/common/modulator.c

@@ -76,10 +76,10 @@ double f_get_next_sample(wave_gen * wg)
 
 	wg->phase += ( (2.0 * PI * wg->Frequency) / (double)wg->sample_rate );
 
-	if(wg->phase > (2.0 * PI) )
+	if(wg->phase >= (2.0 * PI) )
 		wg->phase -= (2.0 * PI);
 
-	if(wg->phase < (-2.0 * PI) )
+	if(wg->phase <= (-2.0 * PI) )
 		wg->phase += (2.0 * PI);
 
 	return sample;

src/common/modulator.h

@@ -30,7 +30,7 @@
 #if defined(M_PI)
 #define PI M_PI
 #else
-#define PI 3.1415926535897932384626433832795
+#define PI ((double)(3.1415926535897932384626433832795))
 #endif
 
 typedef struct iq_wave_gen_