make it modulate a sine wave which is generated live, not sure if works

gen_wave.py

@@ -1,69 +0,0 @@
-PLOT = False
-FFT = PLOT and False
-
-import math
-import io, os
-if PLOT: import matplotlib.pyplot as plt
-if FFT: import numpy as np
-
-DATA_RATE = 1187.5
-
-ratio = 4
-sample_rate = DATA_RATE*ratio
-print(f"{sample_rate=}")
-if not sample_rate.is_integer(): raise ValueError("Need a even value")
-
-PATH = os.path.dirname(os.path.abspath(__file__))
-
-outc = io.open(f"{PATH}/src/waveforms.c", mode="w", encoding="utf8")
-outh = io.open(f"{PATH}/src/waveforms.h", mode="w", encoding="utf8")
-
-header = u"""
-/* This file was automatically generated by "gen_wave.py".
-   (C) 2014 Christophe Jacquet.
-   (C) 2023 Anthony96922.
-   (C) 2025 kuba201.
-   Released under the GNU GPL v3 license.
-*/
-
-"""
-
-outc.write(header)
-outh.write(header)
-
-def generate():
-	t = [i / sample_rate for i in range(ratio)]
-	out = [math.sin(2 * math.pi * DATA_RATE * time) for time in t]
-	print(f"{len(out)=}")
-
-	if PLOT:
-		plt.plot(out*4, label="out")
-		plt.legend()
-		plt.axvline(x=len(out)*2, color='r', linestyle='--', label='center')
-		plt.grid(True)
-		plt.show()
-
-	if FFT:
-		N = len(out)
-		fft_out = np.fft.fft(out)
-		fft_freqs = np.fft.fftfreq(N, d=1/sample_rate)
-
-		plt.figure(figsize=(10, 6))
-		plt.plot(fft_freqs[:N//2], np.abs(fft_out)[:N//2])
-		plt.xlim(0,DATA_RATE*2.5)
-		plt.title("FFT of the waveform")
-		plt.xlabel("Frequency (Hz)")
-		plt.ylabel("Magnitude")
-		plt.grid(True)
-		plt.show()
-
-	outc.write(u"float waveform_biphase[{size}] = {{{values}}};\n\n".format(
-		values = u", ".join(map(str, out)),
-		size = len(out)))
-
-	outh.write(u"extern float waveform_biphase[{size}];\n".format(size=len(out)))
-
-generate()
-
-outc.close()
-outh.close()

src/modulator.c

@@ -1,7 +1,5 @@
 #include "modulator.h"
 
-static float waveform[2][FILTER_SIZE];
-
 void Modulator_saveToFile(RDSModulatorParameters *emp, const char *option) {
 	char modulatorPath[128];
 	snprintf(modulatorPath, sizeof(modulatorPath), "%s/.rdsModulator", getenv("HOME"));
@@ -90,14 +88,7 @@ void init_rds_modulator(RDSModulator* rdsMod, RDSEncoder* enc) {
 
 	rdsMod->enc = enc;
 
-	if(STREAMS > 0) rdsMod->data[1].symbol_shifting.symbol_shift = FILTER_SIZE / 2;
-
-	for (uint8_t i = 0; i < 2; i++) {
-		for (uint16_t j = 0; j < FILTER_SIZE; j++) {
-			waveform[i][j] = i ?
-				+waveform_biphase[j] : -waveform_biphase[j];
-		}
-	}
+	if(STREAMS > 0) rdsMod->data[1].symbol_shift = FILTER_SIZE / 2;
 
 	if(modulatorsaved()) {
 		Modulator_loadFromFile(&rdsMod->params);
@@ -107,8 +98,10 @@ void init_rds_modulator(RDSModulator* rdsMod, RDSEncoder* enc) {
 }
 
 float get_rds_sample(RDSModulator* rdsMod, uint8_t stream) {
-	float *cur_waveform;
-	if (rdsMod->data[stream].sample_count == FILTER_SIZE) {
+	rdsMod->data[stream].phase += 1187.5 / RDS_SAMPLE_RATE;
+
+	if (rdsMod->data[stream].phase >= 1.0f) {
+		rdsMod->data[stream].phase -= 1.0f;
 		if (rdsMod->data[stream].bit_pos == BITS_PER_GROUP) {
 			get_rds_bits(rdsMod->enc, rdsMod->data[stream].bit_buffer, stream);
 			rdsMod->data[stream].bit_pos = 0;
@@ -117,33 +110,10 @@ float get_rds_sample(RDSModulator* rdsMod, uint8_t stream) {
 		rdsMod->data[stream].cur_bit = rdsMod->data[stream].bit_buffer[rdsMod->data[stream].bit_pos++];
 		rdsMod->data[stream].prev_output = rdsMod->data[stream].cur_output;
 		rdsMod->data[stream].cur_output = rdsMod->data[stream].prev_output ^ rdsMod->data[stream].cur_bit;
-
-		uint16_t idx = rdsMod->data[stream].in_sample_index;
-		cur_waveform = waveform[rdsMod->data[stream].cur_output];
-
-		for (uint16_t i = 0; i < FILTER_SIZE; i++) {
-			rdsMod->data[stream].sample_buffer[idx++] += *cur_waveform++;
-			if (idx == SAMPLE_BUFFER_SIZE) idx = 0;
 	}
 
-		rdsMod->data[stream].in_sample_index += FILTER_SIZE;
-		if (rdsMod->data[stream].in_sample_index == SAMPLE_BUFFER_SIZE) rdsMod->data[stream].in_sample_index = 0;
-
-		rdsMod->data[stream].sample_count = 0;
-	}
-	rdsMod->data[stream].sample_count++;
-
-	float sample = rdsMod->data[stream].sample_buffer[rdsMod->data[stream].out_sample_index];
-	if(stream != 0 && rdsMod->data[stream].symbol_shifting.symbol_shift != 0) {
-		rdsMod->data[stream].symbol_shifting.sample_buffer[rdsMod->data[stream].symbol_shifting.sample_buffer_idx++] = rdsMod->data[stream].sample_buffer[rdsMod->data[stream].out_sample_index];
-
-		if (rdsMod->data[stream].symbol_shifting.sample_buffer_idx == rdsMod->data[stream].symbol_shifting.symbol_shift) rdsMod->data[stream].symbol_shifting.sample_buffer_idx = 0;
-
-		sample = rdsMod->data[stream].symbol_shifting.sample_buffer[rdsMod->data[stream].symbol_shifting.sample_buffer_idx];
-	}
-
-	rdsMod->data[stream].sample_buffer[rdsMod->data[stream].out_sample_index++] = 0;
-	if (rdsMod->data[stream].out_sample_index == SAMPLE_BUFFER_SIZE) rdsMod->data[stream].out_sample_index = 0;
+	float sample = sinf(M_2PI * (rdsMod->data[stream].phase - rdsMod->data[stream].symbol_shift));
+	if(rdsMod->data[stream].cur_output == 0) sample = -sample; // do bpsk
 	
 	uint8_t tooutput = rdsMod->params.rdsgen > stream ? 1 : 0;
 	return sample*rdsMod->params.level*tooutput;

src/modulator.h

@@ -17,25 +17,15 @@ typedef struct
 	uint16_t crc;
 } RDSModulatorParametersFile;
 
-typedef struct
-{
-	uint8_t symbol_shift: 7;
-	float sample_buffer[SAMPLE_BUFFER_SIZE];
-	uint8_t sample_buffer_idx : 7;
-} RDSModulatorSymbolShifting;
-
 typedef struct
 {
 	uint8_t bit_buffer[BITS_PER_GROUP];
 	uint8_t bit_pos : 7;
-	float sample_buffer[SAMPLE_BUFFER_SIZE];
 	uint8_t prev_output : 1;
 	uint8_t cur_output : 1;
 	uint8_t cur_bit : 1;
-	uint8_t sample_count;
-	uint16_t in_sample_index;
-	uint16_t out_sample_index;
-	RDSModulatorSymbolShifting symbol_shifting;
+	uint8_t symbol_shift: 7;
+	float phase;
 } RDSModulatorModulationData;
 
 typedef struct {

src/rds.h

@@ -11,8 +11,6 @@
 #define GROUP_LENGTH		4
 #define BITS_PER_GROUP		(GROUP_LENGTH * (BLOCK_SIZE + POLY_DEG))
 #define RDS_SAMPLE_RATE		4750
-#define FILTER_SIZE	 4
-#define SAMPLE_BUFFER_SIZE	(FILTER_SIZE*2)
 
 #define STREAMS 2
 

src/waveforms.c

@@ -1,10 +0,0 @@
-
-/* This file was automatically generated by "gen_wave.py".
-   (C) 2014 Christophe Jacquet.
-   (C) 2023 Anthony96922.
-   (C) 2025 kuba201.
-   Released under the GNU GPL v3 license.
-*/
-
-float waveform_biphase[4] = {0.0, 1.0, 1.2246467991473532e-16, -1.0};
-

src/waveforms.h

@@ -1,9 +0,0 @@
-
-/* This file was automatically generated by "gen_wave.py".
-   (C) 2014 Christophe Jacquet.
-   (C) 2023 Anthony96922.
-   (C) 2025 kuba201.
-   Released under the GNU GPL v3 license.
-*/
-
-extern float waveform_biphase[4];